Dec 082017
BRAINEX Door Manager. All Brainex Doors require the door manager. Makes installation of new doors easy.

Full Description of File

All Brainex Doors require the
Door Manager. Makes installation of
new doors easy! Configures your CDROM,
comports, nodes, etc. Works with most
BBS types. From The Brainex System.
310-275-2344 / 310-273-5234

File BRAINEX.ZIP from The Programmer’s Corner in
Category BBS Files
BRAINEX Door Manager. All Brainex Doors require the door manager. Makes installation of new doors easy.
File Name File Size Zip Size Zip Type
BNXLIST.EXE 2581 1588 deflated
BRAINEX.DAT 20704 6436 deflated
BRAINEX.HLP 7603 2672 deflated
BRAINSET.EXE 197834 87581 deflated
DSZ.DOC 145704 44525 deflated
EXTS1.BAT 67 67 stored
EXTSF.BAT 71 71 stored
EXTSG.BAT 48 48 stored
EXTSH.BAT 28 28 stored
EXTSX.BAT 61 61 stored
EXTSY.BAT 62 62 stored
EXTSZ.BAT 64 64 stored
FILE_ID.DIZ 235 191 deflated
INSTALL.EXE 64862 42405 deflated
LOADER.EXE 78388 50563 deflated
MAXDVWIN.DOC 14150 4059 deflated
NETWORK.DOC 662 362 deflated
PRODUCTS.DOC 7308 3144 deflated
QEMM.DOC 7549 2256 deflated
README! 2536 1196 deflated
REGISTER.DOC 5220 1870 deflated
WHATS.NEW 692 383 deflated

Download File BRAINEX.ZIP Here

Contents of the DSZ.DOC file


1. ZMODEM Features at a Glance.................................... 1

2. TUTORIAL INTRODUCTION.......................................... 3

3. CALLING DSZ FROM COMM PROGRAMS................................. 4
3.1 USE AN INTERFACE PROGRAM?............................... 4
3.2 Ms-Kermit 3.00.......................................... 4
3.3 PROCOMM PLUS............................................ 4
3.4 Qmodem.................................................. 6
3.5 TELIX................................................... 7
3.6 BULLETIN BOARDS......................................... 9

4. DESCRIPTION.................................................... 10

5. COMMANDS....................................................... 12
5.1 List of Commands........................................ 12
5.2 Interrupt Keys.......................................... 18

6. NUMERIC PARAMETERS............................................. 19

7. ENVIRONMENT VARIABLES.......................................... 23

8. EXIT STATUS.................................................... 27

9. EXAMPLES....................................................... 28

10. BACKGROUND OPERATION........................................... 29
10.1 Windows 3............................................... 30
10.2 VM...................................................... 30

11. FLOW CONTROL................................................... 31

12. ERROR MESSAGES................................................. 32
12.1 Got ZRPOS............................................... 33
12.2 Subpacket too Long...................................... 34
12.3 Bad CRC................................................. 34
12.4 Garbled Data Subpacket.................................. 34
12.5 Serial Input Error: Line Status Register xx ............ 35
12.6 No Carrier Detect....................................... 36
12.7 Port %d (%X) defective.................................. 37
12.8 COMMAND NOT FOUND....................................... 37
12.9 Out of Environment...................................... 37

13. SLOW TRANSFERS................................................. 38

14. IN CASE OF DIFFICULTY.......................................... 39
14.1 LOCKUPS................................................. 39
14.1.1 Insufficient Memory 39

14.1.2 Environment TOO BIG 39
14.1.3 Bad COM Port Configuration 39
14.1.4 LAN Manager Conflicts 40
14.2 Incorrect Batch Files................................... 41
14.3 Cheap Internal Modems................................... 41
14.4 Commands Entered in Upper Case.......................... 41
14.5 No Carrier Detect....................................... 41
14.6 DOS 3.x................................................. 42
14.7 Perstor Controllers..................................... 42
14.8 IBM PS/2 Model 50Z...................................... 42
14.9 Brain Damaged UARTS..................................... 42
14.9.1 Everex Internal Modems 44
14.10 Weird Iron.............................................. 44
14.11 PKARC 3.6............................................... 44
14.12 Will the real YMODEM please stand up?................... 45
14.13 286 and 386 Extended Memory............................. 45
14.14 Disk Caches............................................. 45

15. ASSOCIATED DOCUMENTS........................................... 46

16. FILES.......................................................... 47

17. Other Omen Technology Products................................. 49
17.1 Professional-YAM COMMS TOOLS............................ 49
17.2 ZCOMM: Industrial Strength COMMS Shareware.............. 49
17.3 ZMODEM Developer's Collection........................... 49

18. FAIR PLAY...................................................... 50
18.1 Sharing DSZ Files....................................... 51
18.2 REGISTRATION............................................ 52
18.3 Files on Registration Disk.............................. 54
18.4 Bulletin Board Registration............................. 55

19. CHANGES........................................................ 57

20. ACKNOWLEDGEMENTS............................................... 67

Chuck Forsberg

Omen Technology Inc


ZMODEM-90(TM) - Not just another XMODEM hack

DSZ is one of many available programs that implement the ZMODEM file
transfer protocol. DSZ features the ZMODEM-90(TM) extensions including
ZMODEM compression and MobyTurbo(TM) accelerator.

DSZ's ZMODEM provides advanced file management features including two
levels of Intelligent Crash Recovery(TM), and flexible control of
selective file transfers.

The ZMODEM file transfer protocol provides reliable file and command
transfers with complete END-TO-END data integrity between application
programs. DSZ's 32 bit CRC protects against errors that sneak by "error
free" modems and even the most advanced networks.

ZMODEM safeguards all data and supervisory information with effective
error detection. (XMODEM and many recently introduced protocols do not
protect vital supervisory data.)

ZMODEM rapidly transfers files, particularly with modern modems,
timesharing systems, satellite relays, and packet switched networks.
ZMODEM's streaming operation eliminates delays caused by
Kermit/XMODEM/YMODEM/JMODEM block acknowledgements. ZMODEM eliminates
traditional protocols' PACKET LENGTH compromises between transfer
efficiency and error recovery; ZMODEM's packet length is the entire

User Friendliness is an important ZMODEM feature. ZMODEM
AutoDownload(TM) (Automatic file Download without user intervention)
provides a level of convenience unimaginable to users of traditional

DSZ - a ZMODEM-90(TM), True YMODEM(TM), XMODEM File Transfer Program

Omen Technology Inc

1. ZMODEM Features at a Glance

| Feature | ProCm | RZSZ | DSZ | GSZ | ZCOMM | Pro-YAM |
|Security Verification | no | no | no | no | no | YES |
|Cybnertic Data Recovery | no | no | YES | YES | YES | YES |
| | | | | | | |
|Command Download | no | YES | no | no | YES | YES |
| | | | | | | |
|Update Directory Tree | no | YES* | no | no | YES | YES |
| Create Directories | no | YES* | no | no | YES | YES |
| Newer files Only | no | YES | YES | YES | YES | YES |
| Protect files | ? | YES | YES | YES | YES | YES |
| Common files Only | no | YES | YES | YES | YES | YES |
| | | | | | | |
|Collision Aviodance | ? | no | YES* | YES | YES | YES |
| | | | | | | |
|Crash Recoverey | YES | YES | YES | YES | YES | YES |
| Verified Accuracy | no | SZ | YES | YES | YES | YES |
| | | | | | | |
|ZMODEM-90(TM) | no | YES | YES | YES | YES | YES |
| Compression | no | YES | YES | YES | YES | YES |
| MobyTurbo(TM) | no | YES* | YES | YES | YES | YES |
| 7-bit Paths OK | no | YES* | YES* | YES | YES | YES |
| | | | | | | |
|OPERATING SYSTEMS | | | | | | |
| Text Translation | no | YES | YES | YES | YES | YES |
| Record Format Support | no | YES | YES | YES | YES | YES |
| DOS Shared Files | ? | - | YES | YES | no | no |
| OS/2 | no | no | no | no | no | YES |
| VMS | no | YES | no | no | no | YES |
| Unix/Xenix | no | YES | no | no | no | YES |
| | | | | | | |
|True YMODEM(TM) | no | YES | YES | YES | YES | YES |
|Demand Upgrade(TM) | no | YES | YES | YES | YES | YES |
|File Transfer Display | YES | no | no | YES | YES | YES |
| TOTAL File Xfer Data | no | YES | YES | YES | YES | YES |

ProCm = ProComm Plus
* Not available on all flavors or platforms

Chapter 1 Pg 2 DSZ Reference Rev May-3-92 Typeset 5-3-92

DSZ registration is special.
With most programs, registration only applies only to today's version.
Not DSZ!

DSZ registration bypasses the shareware announcement and unlocks
advanced features in all future versions of DSZ. You don't have to pay
and pay again for new DSZ versions. Omen's Demand Upgrade(TM)
technology allows you to download and activate future DSZ versions
without further registration!

Chapter 2 Pg 3 DSZ Reference Rev May-3-92 Typeset 5-3-92


If you are just starting out with DSZ, or if you have difficulty getting
DSZ to work, please follow the procedure given below.

Do not run any TSR or other COMM program. This includes LAN programs.
Reboot a clean DOS if necessary.

Start with the following command given directly from the DOS prompt:

dsz port 1 speed 2400 d t

Type it exactly as it appears above; do NOT use upper case.

(Change the port number and speed as necessary. Use only COM1 or COM2
for testing.)

This connects you to the modem. Dial a bulletin board by typing AT
commands to the modem ("ATDP621-3746 ")[1] to make it dial the
BBS. Log in as usual. Then, request a ZMODEM download of a file you
don't already have. The file will download automatically, you don't
have to do anything. This procedure verifies the correct operation of

Next you might try calling the BBS using a higher "baud rate". This
requires setting a higher speed with the "speed" command. A "handshake
on" command may be necessary along with commands to the modem to enable
hardware handshking in the CTS and RTS leads.

Perhaps you got some error messages before or during the download. The
"ERROR MESSAGES" chapter explains all the commonly seen error messages
and suggests solutions to the underlying problems.


1. If your modem has a non standard setting the ATDT621-3746 command
you type to the modem may not echo on the screen.

Chapter 3 Pg 4 DSZ Reference Rev May-3-92 Typeset 5-3-92


It may be necessary to add the DOS command: SET COMSPEC=C:\COMMAND.COM
(change as needed) to your AUTOEXEC.BAT file to allow programs to call

Note: NO SPACES in the SET command!


A number of third party programs have been developed to provide a
congenial interface to DSZ if you have enough memory to spare. The
XFER, POE, PCALL, DSZ_ZAP, and PROZ programs have been popular in
interfacing DSZ to ProComm's editor gateway. Many of these support GSZ
as well. These programs are available on many bulletin boards.

Hint: the DOS PATH environment variable must include ProComm's directory
to allow POE to locate all the POE files,. The POE files should be
stored in the ProComm directory. Setting the "PROCOMM" environment
variable is insufficient.

Calling DSZ with these programs requires more memory than calling DSZ

3.2 Ms-Kermit 3.00

The "push" command (^[p) in MS-Kermit 3.00 sends an XOFF character to
the modem before calling DOS.

Using this to activate DSZ's term mode with a "dsz t" command causes
most remote hosts to stop. The remote host can be un-wedged by
keyboarding XON (Ctrl-Q) from DSZ's terminal mode.

Add these macros to your MSKERMIT.INI file. Courtesy Keith Petersen

define sx run dsz F port 2 sx 1 2,define 1,define 2,
define rz run dsz F ha on port 2 pY129 rz -r
define sz run dsz F ha bo port 2 pY129 pB4096 sz 1 2,define 1,define 2,
define t run dsz F ha on port 2 pY129 t -r


It's easy to add DSZ to ProComm Plus 2.X.

Datastorm has not licensed ZMODEM-90(TM) technology despite allegations
that DSZ is now "built in" to ProComm Plus version 2. Many users of
ProComm Plus version 2.x use DSZ to get MobyTurbo(TM), Intelligent Crash
Recovery(TM), and other ZMODEM-90(TM) features.

Chapter 3 Pg 5 DSZ Reference Rev May-3-92 Typeset 5-3-92

Make sure the DSZ program is in your search path. If you don't see DSZ
announce itself when called from ProComm, DSZ is not in your search

Here are some handy settings for ProComm Plus.

First, you may need to set the DOS environment before running ProComm.
Give these commands to DOS before running ProComm Plus. (These lines
may be added to your AUTOEXEC.BAT file.)

Note: NO SPACES in the SET command!
SET DSZPORT=2 (Only needed for COM2)
SET DSZLOG=DSZ.LOG (Only if you wish a log file)

Then set ProComm's external protocol strings. From terminal mode hit
ALT-S, then select the PROTOCOL OPTIONS menu item.

From that menu select EXTERNAL PROTOCOL OPTIONS. Then set ProComm's
external protocol strings to:
A- External protocol 1 upload filename: ZMODEMU
B- External protocol 1 download filename: ZMODEMD
C- External protocol 2 download filename: ZMODEMMD

The following batch files are included in the DSZ zipfile:
ZMODEMU.BAT (contains: DSZ sz %1 %2 %3 %4 %5 %6 %7 %8 %9)
ZMODEMD.BAT (contains: DSZ rz)
ZMODEMDR.BAT (contains: DSZ rz -r)
ZMODEMMD.BAT (contains: DSZ rz -mr)
ZMODEMAD.BAT (contains: DSZ t)

!!!!IMPORTANT USE lower case (small letters) EXCEPT WHERE SHOWN!!!!

Select the ZMODEM PROTOCOL OPTIONS menu and turn off Auto downloading!

When sending (uploading) files with ZMODEMU.BAT give the ProComm window
the full pathname (c:/foo/bar/file.ext) for *each* file not residing in
the current directory.

When downloading files with one of the other batch files shown above,
Procomm will also prompt for parameters; just hit ENTER. Or, you can
enter options such as "-mr" if they are't included in the batch file

Once you've got the hang of things the "ProComm way", try the "dsz t"
command described above to give you automatic ZMODEM-90(TM) downloads
(Look Ma, no keystrokes!!!)..

Chapter 3 Pg 6 DSZ Reference Rev May-3-92 Typeset 5-3-92

You can also set the editor hot key (ALT-A) or view program hot key
(ALT-V) by using the ALT-S "FILE/PATH OPTIONS" menu. The strings for
these keys are long enough to store an entire DSZ command line without
need for a batch file.

COM3 and COM4 on Procomm Plus are non standard; in case of difficulty
use COM1 or COM2, or use the portx command.

DSZ may not operate properly when called from ProComm if ProComm has
files open at the time.

A number of reports have been received of problems running DSZ from
ProComm Plus because of insufficient memory. Please refer to the
subchapter on LOCKUPS.

When running under ProComm's Host mode, failure to use the DSZ CON
command may cause ProComm to interfere with file transfers or lock up
the computer.


Hint: the DOS PATH environment variable must include ProComm's directory
to allow POE to locate all the POE files,. The POE files should be
stored in the ProComm directory. Setting the "PROCOMM" environment
variable is insufficient.

3.4 Qmodem

Instability in the Qmodem interface may require changes in the batch
files shown below, depending on which version of Qmodem is used.

If you define a protocol with 'Z' as its letter, the latest Qmodem will
detect automatic ZMODEM downloads. Defining an external 'Z' protocol
disables Qmodem's internal ZMODEM, allowing DSZ to be called.

The following is based on a message from Mike Cody, sysop of HomePlate
313-385-9969 3/12/24/96 HST

Go into Qinstall and go to frame 3 Directories. Then select External
protocols #3 I think. Now you will see a definition area to tell Qmodem
the Letter,batchfile combo to use.

Now put Z in the letter definition, Zup.bat in the u/l batch zdown.bat
in the d/l batch, and Y in the batch protocol. Now save it at the menu
with f10 and S.

Then go to DOS and create the following batch files in your Qmodem

Chapter 3 Pg 7 DSZ Reference Rev May-3-92 Typeset 5-3-92

zdown.bat: DSZ port %2 speed %1 rz -rr

zmdown.bat: DSZ port %2 speed %1 rz -mrr ((FOR MOBYTURBO!!))

zmdown2.bat: DSZ port %2 speed %1 est 0 %3 rz -mrr

zup.bat: DSZ port %2 speed %1 sz %4

!!!!IMPORTANT USE lower case (small letters) EXCEPT WHERE SHOWN!!!!

These are the batch files that will be called by Qmodem. If you did
everything right when you hit PGDN or PGUP you will see an external
protocol called Z) Zmodem in the box. For an easier time do a search for
either External.arc or maybe the string "Qmodem" in the file database as
there is a file with several external protocols and batch files
available in the Mahoney file section (EXEC-PC BBS).

The following batch files for Qmodem are included in the DSZ zipfile:

ZDOWN.BAT contains: DSZ port %2 speed %1 rz -rr
ZUP.BAT contains: DSZ port %2 speed %1 sz %4

!!!!IMPORTANT USE lower case (small letters) EXCEPT WHERE SHOWN!!!!

A variation on the receive batch file:
c:elecomqmodem\* ha slow est 0 %3 rz -mrr
A variation on the send batch file:
c:elecomqmodem\* ha cts est 0 %3 sz %4

If Qmodem says "unable to allocate swap space": QMODEM 4.2 will swap all
but approx. 5K to memory or disk when you shell out to DSZ. Go into
QINSTALL and make sure that /O /R Optimum Shell and Disk Shell are both
set to ON.

For older Qmodem versions (before 4.2) change the %4 in upload scripts
to %3.


Telix has an internal ZMODEM, but some users prefer to use DSZ for
performance and/or reliability reasons. Mat Fisher has published a
Telix script to call DSZ for automatic downloads.

For those of you who use DSZ with Telix, here is a sample script file to use
instead of batch files:

//Protocol salt file for Telix's external protocols by Matt Fisher
//Last edited (02/24/90)
//used for the DSZ ZMODEM protocol. (It will work for u/ling and d/ling)

Chapter 3 Pg 8 DSZ Reference Rev May-3-92 Typeset 5-3-92


str upload[80] =
"c:\telix\protocol\DSZ port 1 pW1 pB4096 ha off sz -b -m -rr ";

str download[80]=
"c:\telix\protocol\DSZ port 1 pW1 pB4096 ha off rz -b -m -rr ";


Main ()
if (_ext_filespec == "")
{ strcat(download,_down_dir); dos(download,0); }
{ strcat(upload,_up_dir); strcat(upload,_ext_filespec); dos(upload,0); }
//////////////////////// THE END /////////////////////////////////////////

Simple but effective...
--- TAGMAIL v2.20
* Origin: CRIMP/John Galt [Node 1] (1:120/144)
INTERNET: [email protected]

NOTE: The DSZ command strings given above are quite unusual. Instead of
the "pW1 pB4096 ha off" one would be more likely to use "ha on" or "ha
sw" depending on the modem's flow control settings.

From : Bill Logan
Subject : Help With Gsz For Telix

I test and use a varity of terminal programs for individuals. One of which is
telix. I found the script language to be less than user friendly and installed
GSZ via batch files and as an external protocol. Here are the batch files:


GSZ pV1 port %2 speed %1 sz -mr %3


GSZ pV1 port %2 speed %1 rz -mrr %3

Then go to ALT O in telix and insert those batch names in the protocols.

They worked fine for me.


Chapter 3 Pg 9 DSZ Reference Rev May-3-92 Typeset 5-3-92

* Origin: PCConsultingAgencyII {=Telecom Node=} (1:300/22)

Use the Telix ALT-O screen to disable Telix's automatic ZMODEM download.


Note to the wise BBS operator: be sure you understand the DSZ restrict
command, how and WHY to use it!

When installing DSZ on a bulletin board or host system, be sure to check
for proper operation when the caller hangs up while a file is being sent
or received.

Some bulletin boards do not call DSZ to send a file until they have
verified the file's presence by actually opening the file. If this
checking is done in DOS's default exclusive open mode, dsz's file
sharing will be defeated.

Chapter 4 Pg 10 DSZ Reference Rev May-3-92 Typeset 5-3-92


DSZ is a "protocol driver" that uses ZMODEM-90(TM), True YMODEM(TM), or
XMODEM to transfer files over a serial port with a variety of programs.

DSZ has two main commands for ZMODEM transfers: "sz" sends file(s), and
"rz" receives them.

When calling bulletin boards to download files with ZMODEM you can avoid
the bother of starting DSZ for each transfer by DSZ's terminal emulator,
before asking the BBS for the download.

dsz t

The "t" command allows you to keyboard the file request directly to the
BBS. (The "t" stands for "terminal emulation".) Just give the "dsz t"
command from DOS or your comms program's DOS GATEWAY. DSZ's ZMODEM
AutoDownload then receives the file automatically, using the filename
provided by the BBS, without any wasted keystrokes or delay. Try it,
you'll like it! (The "t" command is described below.)

YMODEM downloads are almost as easy. Use the "t" command as shown
above, and hit the F3 key after telling the board to download a file
with YMODEM.

ZMODEM and True YMODEM(TM) transfers preserve exact file length and
modification time.

DSZ supports XMODEM-1k (XMODEM with 1024 byte blocks, sometimes
mislabeled as ymodem) and CRC-16 with the sx -k and rc commands.

DSZ is usually called from a communications or bulletin board program.

DSZ uses its own modem I/O. The original interrupt vector, UART parity,
and interrupt configuration are restored on exit. The original state of
the 8259 interrupt mask bit for this vector is also restored on exit.

DSZ uses DOS standard output (stdout) for messages. DSZ never writes
directly to the screen. DSZ expects its standard output to point to the
console, a logging file, or NUL, but never the modem port. If dsz's
standard output is redirected to the modem (as with ProComm's Host mode
DOS shell), the combination will lock up the computer. When necessary,
dsz's standard output can be redirected back to the console device with
the CON command.

Users of pcAnywhere must use the DSZ.EXE A command to disable pcAnywhere
host mode during file transfers.

DSZ and GSZ automatically support Doorway 2.2 without extra commands.

The RZ.BAT and SZ.BAT files are supplied for convenience when operating

Chapter 4 Pg 11 DSZ Reference Rev May-3-92 Typeset 5-3-92

under Doorway. RZ.BAT allows calling programs that emit an "rz" command
to automatically start DSZ from the DOS command prompt. SZ.BAT is a
convenient command interface that complements RZ.BAT. You may modify
SZ.BAT and RZ.BAT with your favorite options.

Chapter 4 Pg 12 DSZ Reference Rev May-3-92 Typeset 5-3-92


Except as noted, all commands and options must be typed in lower case.
Case is significant!

Optional commands or arguments are shown in square brackets [].

When used (in any combination), the A, CON, port, speed, handshake,
estimate, and d commands must be used in exactly this order.

dsz [A] [CON] [F] [port N] [speed S] [handshake XX] [pxN... ] [z pxN...
] [D] [d] [restrict] command

5.1 List of Commands

A Suspend pcAnywhere operation during file transfers (available only
with DSZ.EXE). The A command is used to avoid lockups caused by
pcAnywhere host mode. This command should be given to the DSZ
running under pcAnywhere host mode. Effective for PCA version 4.

NOTE: A bug in the PCA Version 4 API causes the remote to
effectively lock up when DSZ executes the suspend-host command.
Currently the workaround for this bug it to use VT-220 emulation
on the pcAnywhere host and remote instead of pcAnywhere4
emulation. Another possibility is to run AWREMOTE under DESQview,
set the window to SUSPEND AWREMOTE.EXE, and swap windows to a DOS
window from which DSZ, ZCOMM, or Professional-YAM can be run while
AWREMOTE.EXE is forced to remain inert.

The shareware program DOORWAY 2.2 interfaces well with DSZ, and
provides many of the same functions, including the ability to run
direct screen writing applications remotely. DSZ and GSZ
automatically support Doorway 2.2 without extra commands.

EXAMPLE: dsz A sz *.foo Sends files from a pcAnywhere hosted
machine to you.

Fm: Al de la Torre

1 sending from host to remote
type: "dsz A sz filename.ext" ENTER
shell to dos on remote machine (ctrl-Rshift)
type: "dsz A rz" ENTER

Chapter 5 Pg 13 DSZ Reference Rev May-3-92 Typeset 5-3-92

2 sending from remote to host
type: "dsz A rz" ENTER
shell to dos on remote machine (ctrl-Rshift)
type: "dsz A sz filename.ext" ENTER

CON Redirect message output to the DOS "CON" (console) device,
overriding any previous redirections. This is necessary to avoid
lockups caused by ProComm host mode. Most programs do not require
this hack.

F Leave the 16550A UART FIFO enabled on exit. Since DSZ has no way
to read the 16550A DMA mode and trigger level bits, these values
are not restored.

port N select port N (n = 1,2,3,4,5,6,7,8, 10,11,12,13,14,15,16,17,18)
Default is 1 (COM1) or whatever is read from the DOS DSZPORT dos
environment variable. COM11 to COM18 refer to the COM1 to COM8
ports on the PS/2.

Only COM1 and COM2 are standard on all PC compatible computers.
Multiple standards exist for COM3 and above, so use only COM1 or
COM2 when first installing DSZ.

DSZ COM3 uses 3E8 and IRQ4. DSZ COM4 uses 2E8 and IRQ3.

DSZ COM7 uses 2E8 and IRQ5. DSZ COM8 uses 3E8 and IRQ5.

If you wish to use COM3 or COM4 and your computer is not wired as
shown above, you MUST use the "portx" command to specify the
actual base address and interrupt vector.

EXAMPLE: to use COM2:
dsz port 2 rz

In multitasking operation, accessing a port used by another
running program will hang the machine.

portx base,irq To select an arbitrary port address and interrupt vector,
the portx command must be used instead of the port command. The
portx command replaces the portcommand in the same place on the
command line. Please refer to DSZBG.DOC (provided on the
Registration Diskette) or the Professional-YAM or ZCOMM
(ZCOMMDOC.ZIP) manuals for details on this command.

EXAMPLE: dsz portx 2e8,5 speed 19200 handshake on rz

Chapter 5 Pg 14 DSZ Reference Rev May-3-92 Typeset 5-3-92

speed S Set the specified speed. This command is rarely needed because
DSZ reads the port's current speed by default. Please refer to
in DSZBG.ZOO or the ZCOMM or Pro-YAM manual for important
information about the speed command.

Please study all the chapters of this document when using speeds
above 2400 bps.

DSZ supports a maximum speed of 115200. Not all hardware can
support that speed without errors.

handshake XX Enable one of several choices of hardware handshake. (The
default is XOFF/XON software handshake). This command is
documented in the ZCOMM or Pro-YAM manual, and in DSZBG.DOC. (The
ZCOMM manual is available on all bulletin boards registered for
DSZ or GSZ as ZCOMMDOC.ZIP.) On DSZ the "handshake" command may be
abbreviated to "ha".

D Disables the modem (drops Data Terminal Ready, DTR) if carrier is
lost. This may be used to prevent spurious events (phone ringing)
from interfering with the calling bulletin board's recovery from
carrier loss.

d Disables carrier dropout monitoring, for modems that do not
properly drive the "Carrier Detect" input on the PC. If you see a
No Carrier Detect message, you need to give the d command. Before
using the d command, make sure you have the proper port

estimate length [speed] Use the specified length and/or optional
specified effective transfer speed to estimate transfer time for
the next file to be sent or received. The length argument is
mainly used with XMODEM downloads; YMODEM and ZMODEM normally
transfer the file length in the filename packet. The estimate
command must come after any port, speed, or handshake commands.

The estimate command does not affect actual througput. It only
affects DSZ's prediction of how much time a file transfer will

The following makes DSZ calculate file transfer times based on 290
character per second throughput. Some error correcting 2400 bps
modems can attain this throughput when MobyTurbo(TM) is used.

EXAMPLE: dsz port 2 speed 9600 estimate 0 2900 rz

Chapter 5 Pg 15 DSZ Reference Rev May-3-92 Typeset 5-3-92

EXAMPLE: dsz port 2 speed 9600 estimate 0 2900 sz

pxN Set numeric parameter x to N.

DSZ has two sets of numeric parameters, a base set and a "zmodem"
set. Parameters in the base control such things as date stamping
of files, error exit value, etc. The "zmodem" numeric parameters
control timeouts, window sizes, and other ZMODEM, YMODEM, and
XMODEM protocol parameters.

These parameters are mostly a subset of the Pro-YAM/ZCOMM numeric
parameters, and are listed below. They assume their defaults each
time DSZ is called. Without an argument, p displays the numeric
parameters and their values.

EXAMPLE: dsz p

z pxN Set zmodem numeric parameter x to N. All further numeric
parameter commands are taken as zmodem parameters. The zmodem
numeric parameters correspond to the Pro-YAM or ZCOMM "zmodem"
parameters and rarely need changing. These parameters assume
their defaults each time DSZ is called. Without an argument, z p
displays the zmodem numeric parameters and their values.

restrict Restrict incoming pathnames (YMODEM/ZMODEM) to the current disk
and directory tree, and disallow modification or overwriting of
existing files. This command is vital for bulletin boards
uploading files. The restrict command causes partially received
files to be deleted. When DSZ is restricted, it will refuse to
transfer files containing the string autoexec.bat and
in upper or lower case. This provides some defense from malicious
uploaded files.

EXAMPLE: dsz restrict rz

t [-T] [-8g] [-h] [-H] Talk with ZMODEM AutoDownload.

The optional -T forces DSZ to exit after it has recognized a
ZMODEM AutoDownload(TM) request.

The optional -8g (available on registered copies only) enables
reception of "BBS (ANSI) graphics" displays. (A video device
driver such as ANSI.SYS must be loaded to support some types of

The optional -h enables local echo of keyboarded characters ("half

Chapter 5 Pg 16 DSZ Reference Rev May-3-92 Typeset 5-3-92

duplex"). In addition, -H makes the Enter key perform a local
newline (CR/LF).

A small subset of ZCOMM/Pro-YAM term function subcommands are

Keyboard F1 or ALT-X to exit.

F3 receives file(s) with True YMODEM(TM),

ALT-P toggles parity between the 8n default and 8g (enables ANSI

ALT-H toggles two local echo ("Half Duplex") modes; the second
displays a newline (CR/LF) when Enter is keyboarded.

Keyboarded ASCII characters are sent to the modem.

ALT-B sends a break.

Characters from the modem print on the screen. A device driver
such as ANSI.SYS may be used to recognize escape sequences.
Standard ANSI.SYS is limited to a small subset of ANSI escape
sequences; NANSI.SYS, FANSI-Console and other replacement console
drivers provide faster screen updates and better ANSI terminal

DSZ's ZMODEM AutoDownload(TM) detects the start of a ZMODEM file
download and accepts the file(s) without operator intervention.

rz [-abeEmMnpPrt+YZy] [dir] [file ...] (ZMODEM-90 receive) **

rz [-abenprt+Yy] [dir] [file ...] (ZMODEM receive) **

rb [-abt+y] [dir] [file ...] (YMODEM receive) **

rb -g [-abt+y] [dir] [file ...] (YMODEM-g receive) **

rc [-abt+y] file1 (XMODEM/CRC receive)

ro [-abt+y] file1 (XMODEM OverThruster receive)

rx [-abt+y] file1 (XMODEM receive)

rx -g [-abt+y] file1 (Qmodem-G receive) **

** Download directory specification and -g ignored w/o

Chapter 5 Pg 17 DSZ Reference Rev May-3-92 Typeset 5-3-92

sz [-abefnprtFYQS+yZ] [-w[N]] [PREFIX=p | ONAME=n] file ...(ZMODEM

sz [-abeEfmMnpPrtFYQS+yZ] [-w[N]] [PREFIX=p | ONAME=n] file
...(ZMODEM-90 send)

Pathnames are separated by spaces. Wildcards are OK.

EXAMPLE: dsz port 2 sz -r /tmp/file1 /tmp/file3 *.c

The "sz" and "sb" commands exploit DOS's tree structured file
system. A directory or disk specifier expands to all files in
that directory.

EXAMPLE: dsz port 2 sz -r C:srcdir

If you use PREFIX= or ONAME= with the "sb" or "sz" commands, these
pathnames must be entered in lower case unless the underlying file
system supports upper AND lower case.

EXAMPLE: dsz port 2 sz -r ONAME=newsrc.c temp.c

sb [-ft] [PREFIX=p | ONAME=n] file ... (YMODEM or YMODEM-g send)

sb -k [-ft] [PREFIX=p | ONAME=n] file ... (YMODEM-1k or YMODEM-g

sx [-t] file1 (XMODEM, XMODEM/CRC, Qmodem-G send)

sx -k [-t] file1 (XMODEM-1k send)

v Verify the serial number by writing a log entry (see DSZLOG).

v 1 0 bps 0 cps 0 errors 0 128 s/n 666

The letter "v" indicates a verification entry. The first numeric
field is 1 if YMODEM-g is supported. The last field is the serial
number. Unregistered copies show a s/n of 0.

o Turn off Data Terminal Ready (DTR), terminating ("offing") the
connection if the modem responds to DTR. Useful with the "t"
command to disconnect afterwards.

EXAMPLE: dsz t o

Chapter 5 Pg 18 DSZ Reference Rev May-3-92 Typeset 5-3-92

LARG Convert ARG to lower case, then parse arg.

The meanings of optional arguments to the file transfer commands are
described in DSZBG.DOC and the ZCOMM/Pro-YAM manual.

The s (SlugBait) option prevents a receiver from receiving a file
without accounting for it. Attempts to do so are flagged with a Q
status in the log file. This option can cause a transfer that
legitimately fails near the end of the file to be reported as
Questionable rather than ERROR. SlugBait causes DSZ to return success
if at least one file is transferred.

Send files may be specified indirectly:
dsz sz @C:files.lst
sends the files in C:files.lst. This provides another means of
bypassing the DOS command line limit. The first letter must be "@" and
the third letter must be ":" to distinguish this from an ordinary
pathname. Pathnames in the indirection file may be separated by any
combination of space(s), tab(s), CR and/or LF. No spaces may appear
inside a pathname; "FOO .BAR" won't work.

A list of files to send may be built up with a command like:

EXAMPLE: dir *.zip > files.tmp

This file can be edited to remove unwanted files. Then you send the
files with:
DSZ sz -m @c:files.tmp

5.2 Interrupt Keys

Ctrl-Break Terminates the transfer in progress.

ALT-N Abruptly terminates (NUKES) the transfer in progress.

Ctrl-X Typing a dozen Ctrl-X characters to another ZMODEM program
terminates ZMODEM operations.

ALT-F Skips the current file in ZMODEM transfers.

ALT-B Cancels the current ZMODEM session.

Chapter 6 Pg 19 DSZ Reference Rev May-3-92 Typeset 5-3-92


DSZ uses the following main numeric parameters, settable with the pxN

EXAMPLE: dsz pQ0 rz -rr

NOTE: Parameter setting commands such as "pd0" cannot be added to
DSZOPT, they must be included in the command line.

In addition, DSZ uses the Pro-YAM/ZCOMM zmodem numeric parameters
described in the Pro-YAM/ZCOMM reference manual (ZCOMMDOC.ZIP) and in

B Set the size of buffer used for disk reads and writes. The default
is 1024, 4096 maximum (16384 max on GSZ and DSZ.EXE). If your copy
of DSZ is running on a floppy disk system or a very slow turkey hard
disk, a larger value may give better results. Too large a value may
exhaust memory, induce receiver timeouts, cause disconnects(!), or
generate spurious CRC errors. If performance logging doesn't work,
this parameter is too big.

EXAMPLE: dsz pB4096 sz A:floppy.fil

Setting the buffer size may lock out the performance log, DSZFILES,
and/or indirect pathname list in DSZ.COM.


Please understand that the B parameter has nothing to do with
anything you've heard about 128, 1024 or 8192 byte XMODEM style
blocks. Normally, ZMODEM's block size is the entire file!

G This parameter controls the number of bytes loaded into the 16550A
transmit FIFO (First In First Out) storage register on each

For maximum efficiency, DSZ fills the 16 byte transmit FIFO when the
UART generates a FIFO Empty interrupt. Once loaded, data
transmission from the transmit FIFO cannot be stopped, so many bytes
may be sent after the modem sends XOFF or asserts hard flow control
restraint. Good engineering practice requires that modems accept a
large number of bytes after asserting flow control restraint, but
some modems won't.

This parameter is effective only with PCDOS machines using FIFO
buffered UART devices. To improve dsz's responsiveness to flow

Chapter 6 Pg 20 DSZ Reference Rev May-3-92 Typeset 5-3-92

control restraint, set this parameter to 0.


O This parameter controls XMODEM OverThruster(TM). It is described in

P After a "speed" command, if you give a p command (display
parameters), the P parameter value will indicate the type of serial
I/O UART chip detected. DSZ automatically detects and enables the
FIFO on the NS16550A, NS16550AFN, Goldstar GM82C550, and Intel 82510

EXAMPLE: dsz port 1 speed 19200 p

0 Indicates a standard 8250 or 16450 UART with no special features.

1 Indicates an NS16550AN or NS16550AFN with 16 deep receive FIFO.
These are the preferred chips.

2 Indicates an Intel 82510 with 3 deep receive FIFO.

The sequence "port 1 pP1 speed 19200" bypasses DSZ's verification
checks normally performed on the FIFO configuration and may allow
defective FIFO logic on certain chips to be used. This incantation
is not required for the NS16550AN or NS16550AFN.

The sequence "pP-1 speed 2400" should be used with the Western
Digital WD16550 chip to disable the brain damaged FIFO on that chip.
The WD16550 FIFO has been observed to lose data when transmitting at
2400 bps and slower speeds. The minimum speed for normal transmit
FIFO operation with the WD16C550 may vary with different computers.

Q Error code returned to DOS (default 1). (Success always returns 0.)
Some programs toss cookies when confronted with certain exit codes.

EXAMPLE: dsz pQ-1 sz

DSZ reports an error if no files have been transferred, even if the
command used wasn't supposed to transfer any file(s).

R If set to 1, causes partially received files to be deleted.


Chapter 6 Pg 21 DSZ Reference Rev May-3-92 Typeset 5-3-92

S Timeout in seconds (default 15) waiting for restraint release (XON
and/or handshake).

V (DSZ.COM and GSZ only) Set this to 1 to use direct to screen video.
This speeds up displays but may cause serial input errors when CGA
equipped computers are used at high speeds.


sets direct video output.

W Wait for Enter key before exiting after an error. Useful when
calling DSZ from DESQview, allows the window to close unless there
is an error message that should remain visible.

EXAMPLE: dsz pW1 sz

Y Control byte for the NS16550AN/NS16550FAN FCR register. If you
don't know what the FCR does, don't mess with this parameter. It
has been suggested that a different value (129) may improve
multitasking under DESQview when multiple copies of DSZ are active.

a Calibrates certain protocol timeouts used with XMODEM and YMODEM
transfers (Cybernetic Data Recovery(TM)). This parameter does not
affect ZMODEM transfers.

The a numeric parameter is automatically set to 2000 for a 4.77 mHz
PC or XT, 4000 for a PS2/30, 6000 for an 8 mHz 1ws AT, and 12000 for
a PS2/80. If your computer has a speedup card or otherwise runs
unusually fast (or slow!) for its type, you may set the a numeric
parameter to a value that reflects its speed.

EXAMPLE: dsz port 2 pa4000 rb

NOTE: Setting this parameter does not suppress the "Unknown Machine
Type" message which is displayed before the command line is scanned.

d A non zero value (the default) causes incoming files received with
ZMODEM and full YMODEM transfers to have their Date set to that sent
in the file header. ZMODEM's file management features depend on the
transmission of each file's modification date. Files will have the
same creation date, even if the two machines are in different time
zones. When transferring files to/from a Unix system, creation
dates are interpreted according to GMT or Universal Coordinated
Time. File dating may be disabled with a pd0 command, which causes
files to assume the date and time they were received.
NOTE: Backdating file creation times may confuse some backup

Chapter 6 Pg 22 DSZ Reference Rev May-3-92 Typeset 5-3-92

v Verbose level (debugging output) Negative values inhibit some
routine messages. Setting v to 1 or greater causes serialized
copies to ring the bell when a transfer is done.

EXAMPLE: dsz pv1 port 2 rz

z Timezone in minutes behind GMT, used for ZMODEM and True YMODEM file
transfers to coordinate the actual date of the file with computers
in other time zones. PDT or MST corresponds to 420. This may be
preset with the ZONE DOS environment variable.

Chapter 7 Pg 23 DSZ Reference Rev May-3-92 Typeset 5-3-92


The following DOS environment variables may be set to modify DSZ
operation. DOS environment variables are set by giving a command to DOS
before running DSZ. You can add these commands to your autoexec.bat


The following form may be used for arbitrary address/vector


These DOS "set" commands may be placed in your AUTOEXEC.BAT file or
given just before you run your communications program.

IMPORTANT! Do not add spaces to these commands!!

DIRRX (Registered copies only.) Specifies the directory to receive
(download) files. If the sting in DIRRX ends with "/", directory
and/or disk designators in the incoming pathname are stripped, and
only the stem (name and extension) is used. Otherwise, if an
incoming file has an absolute pathname, the incoming pathname is

EXAMPLE: set DIRRX=C:/modem/download/dsz/
dsz rz -r
downloads files to the /modem/download/dsz directory on the C:
drive, with ZMODEM Crash Recovery..


The DOS "set" command defining the receive directory may be placed
in your AUTOEXEC.BAT file. Make certain there is enough environment
space to hold this value. Confirm this by typing "set" to the DOS
prompt and verifying the DIRRX value is listed correctly.

DSZFILES May contain a list of up to 9999 pathnames to transmit, with
entries separated by spaces. If present, DSZFILES is used in place
of a normal command line list of files to send with the sb and sz

EXAMPLE: set DSZFILES=file1 file2 file3 *.c
dsz port 2 handshake on sz -rr

Chapter 7 Pg 24 DSZ Reference Rev May-3-92 Typeset 5-3-92

In practice, this string would be built up by a calling program and
passed to DSZ with a "spawnvpe", "execvpe", or similar subroutine

SEE ALSO: Pathname list specification @C:files.lst

DSZLOG log file to receive entries for files sent and received.
(Default null). Sample entries:

Z 46532 38400 bps 3324 cps 0 errors 66 1024 DSZ.COM 1177
Z 124087 19200 bps 1880 cps 0 errors 6 1024 MXY.TMP 1177

Transfer times are based on the DOS time of day clock and have up to
two seconds' uncertainty. As with all protocol throughput reports
generated by Omen Technology programs (and contrary to the false
claims of some critics), DSZ's throughput figures for ZMODEM,
Kermit, and True YMODEM(TM) transfers do not take "credit" for
pathname and/or protocol overhead characters. DSZ's throughput
reports do not include the time required to send the pathname. This
understates the true time required to transfer files, but the time
required to send the pathname often depends on the alacrity of the
operator, and thus does not always reflect the performance of the
protocol itself.

Transfers measuring less than one second are reported as having 9999
characters per second throughput.

The unlabeled numeric field after the error (retry) count is the
number of flow control stoppages encountered sending the file. Flow
control restrictions are normal when the interface speed exceeds the
communications speed (DTE > DCE). This number gives an indication
of flow control restrictions (overloaded networks, etc.) encountered
during the transfer.

The last numeric field before the file name is the YMODEM block size
or ZMODEM subpacket length used for the last block in the file.

The last field is the serial number of the other program, or -1 if
this information is not available. When sending files, the
receiving program's serial number is not normally available unless
the -S option is used.

The code letter indicates the type of transfer, Z (ZMODEM), S
(X/YMODEM), R (X/YMODEM), E (error), or L (transfer terminated by
loss of data carrier).

WARNING: If DSZ encounters a loss of carrier or other fatal error
condition before a file COMMENCES transmission, a log entry may not
be made.

Chapter 7 Pg 25 DSZ Reference Rev May-3-92 Typeset 5-3-92

EXAMPLE: set DSZLOG=C:/yam/dszlog


DSZOPT (Registered copies only) String containing default options for
DSZ file transfers. Legal option letters for DSZOPT are the
optional modifiers to the DSZ sz, rz, sx, rx, sb, rb commands.

A T may be appended to the string to force DSZ to exit after it has
recognized a ZMODEM AutoDownload(TM) request.

An 8g may be appended to the string to make BBS (ANSI) graphics the
default for DSZ's t command. The ability to preset these options is
especially helpful for controlling ZMODEM automatic downloads from
DSZ's t command.

Enables DSZ's Intelligent Crash Recovery(TM) as a default.

Let's say you wish ZMODEM crash recovery, and BBS "graphics" for the
DSZ term function:
set DSZOPT=r8g

If you're downloading files from GEnie with an MNP modem, the
following will speed up your downloads with Genie's ZMODEM-90Tm.
(You can recognize ZMODEM-90 on GEnie two ways: 1) MobyTurboTm is
used to speed ZIP and ARC downloads, 2) "sz 4.xx" is displayed at
the end of transfer. As of this writing, ZMODEM-90 may not be
available in all libraries.) Note that (as usual with DSZ) case is
significant: the "r" must be lower case, the "W" upper case.
set DSZOPT=rW16384

WARNING: Do NOT include "ena" or any other commands in the DSZOPT
string. With the exception of the "8g" mode, only **options** may
be placed in the DSZOPT string! (Options are the letters that
modify the sz, rz, sb, etc. commands. In "rz -r", "r" is an

Parameters can not be set in DSZOPT.

MAXBYTES Maximum number of bytes allowed for transfer. If this number
is exceeded, DSZ skips the offending files (ZMODEM) or aborts
remaining files in the batch (YMODEM).

DSZPORT Default communications port override, default 1.


Chapter 7 Pg 26 DSZ Reference Rev May-3-92 Typeset 5-3-92


ZONE sets the z numeric parameter to the number of minutes the current
local time lags GMT time. PDT or MST corresponds to 420. PST
corresponds to 480.
set ZONE=420

Chapter 8 Pg 27 DSZ Reference Rev May-3-92 Typeset 5-3-92


DSZ exits with 0 status for successful transfers, or the value of the Q
numeric parameter (default 1) if a file transfer failed, or if no files
were transferred. Many languages and "door" programs do not return this
information to the calling program. Some languages and "door" programs
freak out (hang) on certain non-zero exit values.

A batch file that calls DSZ directly may be used to detect the DSZ exit
status with the DOS "errorlevel" construct. Please refer to the Q
numeric parameter below for more information.

DSZ's log file entries may also be examined to determine the success or
failure of a file transfer.

DSZ commands are an improper subset of Pro-YAM/PowerCom/ZCOMM commands.
The file transfer commands are fully described in ZCOMMDOC.ZIP, the
ZCOMM User's Manual. Portions of the ZCOMM User's Manual are also
provided in DSZBG.ZOO. You may refer to one of those documents for
details on the following commands.

Chapter 9 Pg 28 DSZ Reference Rev May-3-92 Typeset 5-3-92


dsz sz (send 1 file with ZMODEM)

dsz sz -m c:*.zip (send all .ZIP files with MobyTurbo(TM))

dsz sz f1.c f2.c f3.c (send 3 files with ZMODEM)

dsz sz c:foo.* b:*.c (send multiple files with ZMODEM)

dsz sz -Z *.lst (send text files with ZMODEM compression)

dsz sz -r (CRASH RECOVERY: resume interrupted

dsz rz -r (CRASH RECOVERY: resume interrupted

dsz rz -rr (CRASH RECOVERY with file comparison)

dsz handshake both sz (Hardware+Software handshake)

dsz sz -n *.* (send files that are newer or rx has no

dsz sz -Yn *.* (Only send files that are newer than
receiver's copy)
(Do not send files that do not exist on
receiver's disk)

dsz rz C:/UPLOADS (receive files to specified directory *)

dsz port 2 speed 38400 handshake both restrict rz
(Restrict provides protection for BBS's)

dsz rz -y (ZMODEM, single file pathname override)

dsz z pr1 rx foo.dat (XMODEM receive, remove file if error)

dsz pO60 ro foo.dat (XMODEM/OverThruster receive, GEnie MNP *)

DSZ LRC L-Y NEWPROG.ZIP (generate lower case "rc -y" command)

dsz sz foo >debug.dmp (Debugging data dump)

dsz sz @C:/bbs/files.lst (Indirect file list)

dsz sz -u *.lst (Unlink (Delete) files as they are sent)

* Registered copies only

Chapter 9 Pg 29 DSZ Reference Rev May-3-92 Typeset 5-3-92


Three DESQview description files are provided to demonstrate background
operation with modest (66 kb window) memory requirements. DSZ uses
tight C/ASM code, table driven CRC generators, and buffered receive and
transmit for good performance in the background without hogging CPU
cycles. On a QIC Labs 8 mHz PC-AT clone, DSZ can download files in the
background (3 background clock ticks, 9 foreground clock ticks) with a
throughput better than 9600 bps.

GSZ operates under DESQview with 128k of memory.

HINT: make sure "Separate Shift State" is set to "N".

2S Prompts for file name(s) and sends them with ZMODEM protocol.
File: 2S-PIF.DVP

2T Talks to the modem and allows manual YMODEM (F3) or automatic
ZMODEM downloads. File: 2T-PIF.DVP

2A Like 2T, but using Quarterdeck's memory resident ANSI
CRT device driver to process ANSI screen codes. File: 2A-PIF.DVP
DS.BAT is the batch file used by 2A.

These files are written for a port 2 local connection and \TMP
directory, but may be modified to suit your requirements using the
DESQview CP command. The W numeric allows DESQview to close the window
after DSZ finishes, providing a pleasant user interface.

Other DVPs, Scripts, and Batch files are available on the DESQView
conference on the Sound of Music as DVDSZ20Z.ARC.

Please consult the DESQview documentation for instructions on
installation procedure for the DVP files.

Operation at high speed (above 9600 bps) may require the DESQview
"Optimize communications" performance Advanced Setup option.

Newer versions of DESQview may require more "common memory" allocation
(6-8 k bytes) to operate with DSZ. Some versions of DESQview do not
operate properly with DSZ; DESQview 2.0 is known to work, and DESQview
2.25 is reported to have fixed bugs in intermediate versions.

On 286 and 386 machines, some DESQview operations involve swapping
memory contents with buffers in extended memory. As with extended
memory ramdisks and disk caches, this causes errors with high speed
communications. The considerations discussed in the "286 and 386
Extended Memory" subchapter apply here. Since this DESQview extended
memory swapping is asynchronous with respect to DSZ's file transfers,
"handshake slow" doesn't help here. The solution is to force DESQview's
memory swaps to use smaller blocks (with interrupts allowed between

Chapter 10 Pg 30 DSZ Reference Rev May-3-92 Typeset 5-3-92

blocks) and/or use NS16550AN or NS16550AFN or Goldstar GM82C550 chips
for the serial interface.

If you see funny characters on the screen while a program is loading,
you have a conflict between the display adapter and QEMM memory manager
which may cause lockups. If so you must explicitly exclude the display
adapter's memory with an EXCLUDE clause in QEMM's config.sys entry.

When running DSZ under a multi tasking system such as DESQview, do not
allow two programs to access the same comm port at the same time. At
best, such actions will disrupt communications. At worst, your computer
will attempt to open a subspace channel to V'ger.

Tell DESQview to use the SPECIFIC port number you are using, and not "Y"
to the question: "Uses serial Ports (Y, N, 1, 2)"

When running a comm program under DESQview or any related multitasking
executive, DSZ must be called directly from the comm program, in the
same window. DO NOT open a separate window for DSZ unless you were
about to power down the computer anyway.

With some communications programs, you can make the call, log in, and
then exit (closing the window) without disconnecting the modem. At this
time you can fire up DSZ with the "t" command to allow YMODEM or ZMODEM
downloads in a small window.
Example File: 2A-PIF.DVP

Alternatively, you can start DSZ from the DOS prompt, then type "AT"
commands to the modem to call the bulletin board. DESQview's "learn"
facility may be helpful here.

10.1 Windows 3

Communications programs do not operate well under Windows 3 because
Windows does not have true multitasking.

10.2 VM

According to Marshall Sutherland, Be sure to set IOPL3 mode to YES.

Chapter 11 Pg 31 DSZ Reference Rev May-3-92 Typeset 5-3-92


If you plan to send files over Telenet (PC-Pursuit), you must refer to
the Pro-YAM or ZCOMM Reference manual (in ZCOMMDOC.ZIP) FLOW CONTROL
chapter for vital information on flow control considerations necessary
for proper operation of ZMODEM and other streaming protocols.

Chapter 12 Pg 32 DSZ Reference Rev May-3-92 Typeset 5-3-92


COM2 1200 bps Carrier Detect enabled Handshake slow
Command line = (commands)
This is a normal message displayed to help resolve problems with
incorrect batch files. The port number, speed, carrier detect
("enabled" or "DISABLED") and "handshake" indicate the selected mode of

DSZ FINISHED! exit code = 0
This is DSZ's normal exit when at least one file has been transferred
and no unrecoverable errors have been detected. If an error such as a
failed file transfer had been detected, the exit code would be 1, or the
value set in the Q numeric parameter.

As the message implies, DSZ has done all of its processing, and has
return the communications port and vector to its original value before
displaying this message. If the computer locks up after this message is
displayed, there's something wrong with the program that called DSZ, not
with DSZ itself.

Unknown Machine Type XX, 'a' parameter preset to 6000 indicates a ROM
BIOS that does not follow the IBM specification for identifying the
machine type. If your computer causes DSZ to display this message, you
may set the a numeric parameter described elsewhere in this document.
This message is generated before any commands are read, so do not be
alarmed when you "discover" that setting the a parameter doesn't make
this message go away. The a parameter does not affect ZMODEM transfers.

Please send us a postcard or letter indicating the reported hex value
for machine Type, name of the computer, and its speed so we can include
that machine type in a future release.

Need more memory to run DSZ or Abnormal program termination is displayed
by the TurboC startup routine if DSZ is run in too small a memory
partition. If you see this message, use a larger memory partition for
DSZ or remove some memory resident programs. This message may also
appear if the calling program fails to free memory before calling DSZ.

No Carrier Detect is displayed when DSZ recognizes a lack of carrier
detect signal from the modem. Most support calls concerning "No Carrier
Detect" are caused by the user failing to tell DSZ to use the correct
port. DSZ does not magically divine the COM port number; if the default
COM1 is incorrect, DSZ must be told what port to use with the port
command or the DPORT environment variable.

No Carrier Detect may also be caused by a line disconnect, defective
cable, or incorrect modem strapping. It may be disabled with the d
command. Sometimes this is caused by setting the B parameter to too
large a value.

Chapter 12 Pg 33 DSZ Reference Rev May-3-92 Typeset 5-3-92

Garbage Count Exceeded Indicates ZMODEM has not detected a valid start
of header in a reasonable number of characters.

If DSZ becomes "stuck" on emitting this messages, it is possible the
sending program may not be able to recognize and act upon transmission
requests (ZROPS headers). The sending program should be corrected. In
the meantime, setting a ZMODEM packet length with the "zmodem pl4096"
("l" is the small letter l) command will force the sender to wait for
the receivers' progress reports.

Permission denied comes from the Microsoft C Library. This is caused by
attempts to modify a read only file or directory, or to create a file in
a nonexistent directory.

Appearance of XOFF or FLOW during ZMODEM or YMODEM-g file sending
signifies DSZ is responding to flow control restraint. This is normal
operation when error correcting modems or packet switched networks are
used. ZMODEM's robustness and reliability allow creative users to
transfer files over unusual multiple computer lash-ups, causing modem
data lights and computer status displays to dance in unfamiliar rhythms.

Output FLow Control Restraint RELEASED Indcates DSZ has not received a
positive flow control signal (XON and/or CTS as specified by the
handshake command) within the timeout specified by the S numeric
parameter. This message may appear as the result of line noise. If it
appears often, it may indicate improper flow control settings, defective
modem and/or cable, or (rarely) too small a value for the S numeric
parameter. A TSR program that monitors ring detect has also caused this

Not allowed to overwrite %s By default, DSZ will not overwrite an
existing file. Use the -y or -n or -r option to overwrite/update
existing files.

12.1 Got ZRPOS

Got ZRPOS indicates the receiving program has detected a transmission
error and has requested retransmission. In other words, ZMODEM is doing
its job of detecting and correcting missing and garbled data.

If this happens with error correcting modems, or more often than
observed line noise would suggest, the receiver's error messages must be
studied. "Line Status Register 01" messages indicate a flow control
problem. "Line Status Register 02" messages suggest a receiver problem
with interrupt latency.

Otherwise, the sender may have a flow control problem in one of four

Chapter 12 Pg 34 DSZ Reference Rev May-3-92 Typeset 5-3-92

+ Between the sending program and its modem. If using an interface
speed higher than the transmission speed, or modem to modem error
correction (MNP, LAPB, PEP, etc.), check that the modem and the
sending program are configured for the same flow control methods.
Omen Technology's software is faster than most other programs, and
may expose flow control problems not seen with slower software.

+ Between the sending modem and the network. Correcting this requires
"handshake both" to allow the sending program to honor both hardware
(CTS) flow control from the modem and software flow control
(XON/XOFF) from the network.

+ Between parts of the network, or between the host computer and its
terminal server(s). We have received a number of reports of
problems with Cisco terminal servers.

+ Between the receiving modem and the receiving program. This can
happen at high transmission speeds when the receiver has specified a
large I/O buffer size with the B numeric parameter.

Excessive interrupt latency from extended memory ramdisks or disk
caches, and poorly written hard disk drivers also wreak havoc on
streaming protocols but do not affect start-stop protocols (XMODEM,
etc.). Problems with extended memory disk caches may cause errors
at regular intervals; check the receiver's error messages.

To work around these problems, give the "handshake slow" command to
the receiver.

12.2 Subpacket too Long

This error may be caused by flow control problems at the sender (see

12.3 Bad CRC

This error may be caused by flow control problems at the sender (see

12.4 Garbled Data Subpacket

This error may be caused by flow control problems at the sender (see

Byte NNNN retry M: These messages appear when the
protocol has detected an error and is attempting to retransmit the
garbled data. These are normal messages.

Chapter 12 Pg 35 DSZ Reference Rev May-3-92 Typeset 5-3-92

12.5 Serial Input Error: Line Status Register xx

Serial Input Error: Line Status Register HH indicates a hardware
problem, slow device driver, TSR program, or other software is disabling
interrupts too long for the program to accept incoming data, and some
characters are lost. A slow response to folow control also triggers
this message.

The value of the line status register is displayed in HEX. The
following error conditions are OR'ed into the Line Status Register.

01 The Interrupt level circular buffer has been overrun. This
indicates a flow control problem. The remote did not respond to
DSZ's XOFF or hardware flow control signal, and continued to send
characters after being told not to. This problem is alleviated by
matching flow control between the sending computer, modems, and the
receiving computer. Usually, the mismatch exists between the
sending computer and its modem.

02 An 02 value for the LSR indicates Data Overrun. "Data Overrun"
means the computer was not able to respond to an incoming character
from the UART (modem) in time to make room for the next incoming
character. Data Overruns are caused by poorly designed software
(or ROM BIOS "firmware") locking out interrupts for excessive
periods. These lockouts prevent the communications program from
responding to the incoming characters quickly enough.

Common causes of excessively long interrupt lockouts ("critical
code regions") are disk drivers (BIOS), window managers (Windows 3
is terrible), disk cache programs, TSR programs, and EGA/VGA board

Slowing the CPU to allow games and other time dependent programs to
be used can generate excessive interrupt latency.

Some BIOS programs are written without regard to their effect on
high speed communications. Better versions of the offending BIOS
programs may be made available if enough users complain about poor

Interrupt latency caused by EGA/VGA board auto-select can be often
corrected by disabling the board's Auto-Select.

Poorly written disk caches and disk drivers cause interrupt latency
that affects streaming protocols (ZMODEM) but not start-stop
protocols such as XMODEM, YMODEM, JMODEM, Lynx, etc.

To correct Data Overruns, you must correct the offending
condition(s) to allow the communications program to operate

Chapter 12 Pg 36 DSZ Reference Rev May-3-92 Typeset 5-3-92


The handshake slow command can be used to stop reception during
disk transfers. However, handshake slow is not always an effective
alternative to correcting the real problem.

Other chapters in this document give suggestions for working around
excessive interrupt latency by using the NS16550AN UART chip.
Please refer to the "Brain Damaged UARTS" subchapter.

Please try all the suggestions mentioned here before contacting
Omen Technology about data overruns.

08 Framing Error generally caused by line noise or an incorrect
transmission speed ("baud rate") or format (number of bits). Also
caused by some cheap internal modems. Most protocols require 8
bits no parity (-8n) for proper operation. This is set
automatically by Omen Technology programs, but other programs may
not be so smart.

10 Break Interrupt generally caused by line noise or an incorrect
transmission speed ("baud rate") or format (number of bits). Also
caused by some cheap internal modems.

18 Framing Error and Break Interrupt (see above) in combination.

This error may also be caused by defective 8250 UART chips. Some
internal modem cards have slow 8250 chips that do not operate
properly with computers faster than 4.77 mHz. Replacing the 8250
with a NS16550AN is recommended. Please refer to the "Brain
Damaged UARTS" subchapter for details.

Please refer to the In Case of Difficulty chapter of this document for

Less commonly encountered DSZ error messages are explained in the Pro-
YAM manual.

12.6 No Carrier Detect

If you see a No Carrier Detect message, and you haven't lost the
connection, you should fix your modem cable or modem settings to allow
proper operation of the Carrier Detect signal (CD).

A poorer alternative is to give the d command: dsz port 1 speed 2400 d

Chapter 12 Pg 37 DSZ Reference Rev May-3-92 Typeset 5-3-92

12.7 Port %d (%X) defective

When DSZ selects a serial port, it performs a quick hardware check to
verify the presence and minimal functionality of the 8250 family UART.
This message usually means a nonexistent port has been selected.

Reports have been received of functional but nonstandard UART chips
triggering this message.


If you see this message, make sure DSZ is in the DOS PATH. Sometimes
this error is caused by having too many environment variable strings.

12.9 Out of Environment

means there is not enough room in the program environment to accept more

DOS prints this message when it cannot allocate more memory to
accommodate a "set" command, such as "set dirrx=c:/downloads/".

Try moving the "set" commands to the batch file that calls your comms
program, or to your AUTOEXEC.BAT file.

To increase environment, use the /E switch. The default is 160 bytes.

An example for your CONFIG.SIS file: SHELL=C:COMMAND.COM/E:256

NOTE: Large environments may cause DSZ.COM to lockup. This is less of a
problem with DSZ.EXE.

Chapter 13 Pg 38 DSZ Reference Rev May-3-92 Typeset 5-3-92


Some users report slower than expected file transfers even when few or
no errors are reported. Some possible causes are:

If "handshake slow" is used, throughput may suffer. Try one of the
other solutions to the "Line Status Register = 02" errors discussed
above. When using "handshake slow" it may be possible to increase the
modem's interface speed to 19200 bps or faster.

Bad phone lines will silently slow MNP modems, sometimes without any
error indications. If the modems disconnect fairly often you should
suspect marginal phone line conditions that are being hidden by MNP
error correction.

One of the programs may have set a parameter or option that acts to slow
the transfer under certain conditions.

Chapter 14 Pg 39 DSZ Reference Rev May-3-92 Typeset 5-3-92



14.1.1 Insufficient Memory
DSZ complains when it detects insufficient memory to operate. When
calling DSZ from another program, there may be ALMOST enough memory for
proper operation, but DSZ locks up during a transfer or the calling
program freezes after DSZ displays the "DSZ Finished" message.

Sometimes there is a message about insufficient memory, sometimes just a
lockup and no message. To verify this problem, call CHKDSK from within
your comms program (not from DOS!) by defining it as an external
protocol. If you use an interface program (Hotkeyz, Prodoor, etc.), you
must call CHKDSK from that program, as those programs also reduce the
memory available to DSZ.

CHKDSK should report at least 64k free memory. If less memory is
reported, reduce the size of the COMMS program's capture buffer, or
reboot the system with fewer/smaller device drivers and TSR programs.
Calling DSZ directly from the comms program instead of from an interface
also saves memory.

14.1.2 Environment TOO BIG
A large environment may cause DSZ.COM to lockup. The size of the
environment (the amount of text you get when you give the DOS "set"
command) is subtracted from the data space available to 8086 C programs.
This can be a problem with DSZ.COM, whose 8086 tiny model limits code,
data, stack, and environment to 64 kb TOTAL. Use DSZ.EXE (compiled with
8086 small model) to alleviate this problem.

14.1.3 Bad COM Port Configuration
DSZ is fastidious about which interrupt vectors it takes over. Unlike
some programs, DSZ uses only the correct interrupt vector for its
interrupt service routine. (This allows multitasking.)

DSZ obtains and releases this vector with standard DOS function calls.
This allows multi line operation under DESQview and other multitasking

Incorrectly configured serial ports that work with programs that pig out
both IRQ3 and IRQ4 will lock up with DSZ. If DSZ locks up the machine
as soon as it tries to send or receive data, this is usually the fault.
Make sure the comm port is strapped correctly; COM1 uses IRQ4, COM2 uses
IRQ3. DSZ will lock up if the comm port is not properly set up.

In addition, DSZ will not work properly if two devices are connected to
the same IRQ line, even when some other programs (that don't use
interrupts as intensively) do work normally on the same machine.

Chapter 14 Pg 40 DSZ Reference Rev May-3-92 Typeset 5-3-92

COM3 and above are not widely standardized. If you have problems with
COM3, chances are your "COM3" is non standard.

14.1.4 LAN Manager Conflicts
Some Local Area Network (LAN) managers take over comm ports using code
that interferes with DSZ.

The following hint is from Tom Louvaris, LANtastic Sales/Support - New
York. Other LAN mamagers may require similar incantations to keep the
LAN manager from messing with DSZ's comm port.

Problem: When the lan is running, DSZ intermittantly fails. DSZ starts
the transfer by displaying "Ready to send pathname". The receiving
system does noting. Eventually, DSZ exits with code 1, and no file is

To release one or more Com Ports with LANtastic 3.x, enter the

Net Queue Halt \Sever-name Comn

Note: You must be logged on to "Server-name" with Queue priveleges to

Chapter 14 Pg 41 DSZ Reference Rev May-3-92 Typeset 5-3-92

enable the operation of this command.

14.2 Incorrect Batch Files

Incorrect batch files are the number one source of problems using DSZ
for uploads and downloads. Bulletin board programs with convoluted
batch file mechanisms exacerbate the problem.

DSZ's command line echo was added to assist in correcting defective
batch files. You should see a display like:

Command line = 'rz '
Command line = 'port 2 speed 9600 sz foo.baz '

You may have to add a "pause" command at the end of the batch file to
allow DSZ's messages to be seen. Another possibility is to turn on the
printer with ^P before running DSZ, so DSZ's message can be saved on

In general, the Command line display should look like one of the
examples in this document or those displayed by DSZ itself. (The
Command line display does not include the name of the DSZ program

Try running DSZ by itself, without any batch files or TSR programs,
calling it directly from DOS as described above.

14.3 Cheap Internal Modems

Numerous trouble reports have been received lately caused by cheap
internal modems causing errors on ZMODEM transfers but not XMODEM. A
similar problem was experienced in the mid 80's during beta testing of
some 2400 bps modems. Perhaps defective LSI chips left over from those
days were cloned or recovered from the trash bin.

14.4 Commands Entered in Upper Case

Most DSZ commands and options must be entered in lower case (small
letters, not big letters). Where the documentation or help screen
indicates "rz", you must use "rz" and not "RZ".

14.5 No Carrier Detect

If you see a No Carrier Detect message, and you haven't lost the
connection, you should fix your modem cable or modem settings to allow
proper operation of the Carrier Detect signal (CD).

Chapter 14 Pg 42 DSZ Reference Rev May-3-92 Typeset 5-3-92

A poorer alternative is to give the d command: dsz port 1 speed 2400 d

14.6 DOS 3.x

DOS 3.x systems may need to have a "STACKS = 8,256" line in CONFIG.SYS
to prevent antisocial behavior. This is required on the NEC Multispeed,
or if certain TSR's are used.

14.7 Perstor Controllers

Several reports have been received indicating Perstor disk controllers
interfere with data communications. Perstor is reportedly working on a

14.8 IBM PS/2 Model 50Z

Early samples of this machine have a design error on the motherboard
that causes comms programs to lock up the machine. Replacing the
motherboard with a correctly functioning unit from current production
corrects the problem. The part number of the replacement PS2/50 Z
motherboard is 35F5928. (Information provided by John M. Choma
73047,3566) U.S. IBM stonewalled on this issue, but in December 1988
agreed to replace the defective motherboards under warranty.

14.9 Brain Damaged UARTS

Omen Technology has received reports of problems with buggy 8250 type
UART integrated circuits in Leading Edge modem boards, serial port
interfaces, and computers. The defective chip logic affects high
performance software. Replacing the buggy chip with a newer chip
(NS16550FAN) corrects the problem.

The UM82450 chip in the Zoom 2400HC also appears to cause problems.
Zoom Telephonics advises that this problem is limited to their old
model. The old model is inentifiable by an external volume control.

You can identify an old chip by inspecting the serial interface board
for 8250 or UM82450 type devices. A service technician or hardware
hacker can help if you are not familiar with reading chip numbers.

Dsz users can identify old chips with the following software command:

EXAMPLE: dsz port 1 speed 2400 p

ZCOMM and Professional-YAM users can look at the printout produced by
the s command; old UART chips register as TYP 0.

Chapter 14 Pg 43 DSZ Reference Rev May-3-92 Typeset 5-3-92

The National Semiconductor NS16550FAN is a pin compatible plug in
replacement for 8250 and 16450 serial chips. Omen Technology PCDOS
software enables the FIFO buffer in the NS16550FAN to prevents loss of
data from poorly written device drivers, TSR programs, etc.

We are also using the Goldstar GM82C550 chip with a 9025 date code.
This Goldstar chip is plug compatible with the National chips. No
problems have been discovered with this chip.

The NS16550FAN has better electrical characteristics than the older UART
chips. 386 and fast 286 machines should use the NS16550FAN for best
results. Omen Technology software has been written to allow time for
the older UART chips to operate. However, there is a limit to how much
the software can rearrange chip accesses without resorting to
performance robbing wait loops. Some other software is not as forgiving
of slow chips.

Be sure to ask for the NS16550FAN. It is VITAL to get the National
Semiconductor "AFN" or "AN" chip. Other vendors' chips not mentioned
above won't do. Current Western Digital WD16C550 chips do not function
properly at low speeds.

As of this writing, the Goldstar GM82C550, National Semiconductor
NS16550AN and NS16550FAN are the only plug compatible chips that are
known to work.

The Hayes ESP board comes with two serial ports with NS16550FAN devices.
The ESP definitions for COM3 and COM4 agree with the industry standard
definitions used by Omen Technology. All option switches on the ESP
board should be OFF except those used to select the port number (COMn).

The following information comes from a number of people:

"I have located a small dealer in New York who has the cards with or
without the 16550. I believe the price is around $50.00. The company
is RJK Consulting and the number is 718-968-9167. The gentleman to speak
to is a Mr. RJ Kulman. ... I got this information off the "Interlink"
BBS system." Fm: Nick Braak [TRICON] 75156,1254

Fry's - 415-770-FRYS. This is a Silicon Valley electronic department

Jameco Electronics at 415-592-8097 sells National NS16550FAN chips mail
order (credit card) in small quantities. Unfortunately, we have
received a number of reports that their serial i/o card is now supplied
with the infamous WD16C550 soldered in, even when ordered with specific
instructions to include 16550FAN chips.

Microprocessors Unlimited, 24000 South Peoria, Beggs, OK. (918) 267-
4961. The price for the chip is $13.50 plus shipping costs. No minimun
purchase is required.

Chapter 14 Pg 44 DSZ Reference Rev May-3-92 Typeset 5-3-92

Consolidated Computers 4 Shoppers Lane Suite 121 Turnersville, NJ 08012
(609)751-9595(voice) (609)751-3843(bbs) (609)751-3840(fax)

Arrow Electronics at 800-932-7769 (516-467-1000).

Willies Computer Software Company: 800/835-4832.

N.B.: Current Western Digital WD16C550 chips do not function properly at
low speeds. This has been confirmed with samples received directly from
Western Digital. WD is aware of this problem, but has not informed us
of a corrected chip.

14.9.1 Everex Internal Modems
Numerous reports have been received concerning difficulties with Everex
modem cards. Some of these cards contain buggy 8250 chips which are not
up to the demands of full duplex streaming protocols such as ZMODEM.
Replacing the buggy 8250 chip with NS16550AN chip corrects these

14.10 Weird Iron

A few machines, some with V20 CPUs, reportedly don't like DSZ.COM. We
have not been able to repeat this; TeleGodzilla (using a V20) runs
DSZ.COM without a hitch. Switching to DSZ.EXE has cleared up the
problems on other machines.

14.11 PKARC 3.6

It has been reported that PK36 grabs some interrupts and doesn't restore
them on exit in an attempt to prevent hacks of the program. Since
eliminating that particular version and cleaning up memory, high speed
transfers even with 8250 UARTS work properly again.

The problem with PK 3.6 appears to be most severe if a BBS operator has
doorware, etc that accesses the PK programs from a shell of some sort.
This info may be helpful to users who are having otherwise inexplicable
file transfer problems.

Phil Katz has written me that this problem has been corrected in
subsequent versions.

Chapter 14 Pg 45 DSZ Reference Rev May-3-92 Typeset 5-3-92

14.12 Will the real YMODEM please stand up?

Some XMODEM programs claiming to support YMODEM neither send nor accept
the YMODEM pathname block. 1024 byte XMODEM is XMODEM-1k, not the
YMODEM defined by Ward Christensen in 1985 when he invented the term
YMODEM. 1987 and later versions of YMODEM.DOC remind the reader of the
official YMODEM definition, which has not changed since YMODEM's coinage
in 1985.

14.13 286 and 386 Extended Memory

Virtual memory disk caches and ramdisks using 80286 or 80386 extended
memory require a kludge hardware reset of the CPU chip to return to the
normal "real mode" after accessing extended memory. This interference
to the interrupt response time causes lost characters on comm ports, and
may be minimized by specifying shorter memory transfers.

Switching to a Goldstar GM82C550, National NS16550AN or NS16550AFN UART
chip helps tremendously, allowing transfers at 115200 bps instead of
9600 bps with a standard 8250. Please refer to the subchapter on "Brain
Damaged UARTs". The DSZ "handshake slow" command may also help.

14.14 Disk Caches

Cache programs often interfere with ZMODEM transfers. In one instance,
replacing Microsoft's SMARTDRV.SYS with Multisoft's SUPERPCK.EXE helped.
Norton NCACHE and and Multisoft PCQWIK have also caused errors.

Some cache programs can be turned on and off; try turning it off when
running DSZ.

Switching to a National NS16550AN or NS16550AFN UART chip helps
tremendously, allowing transfers at 115200 bps instead of 9600 bps with
a standard 8250. Please refer to the subchapter on "Brain Damaged
UARTs". The DSZ "handshake slow" command may also help.

Chapter 15 Pg 46 DSZ Reference Rev May-3-92 Typeset 5-3-92


Consult the Professional-YAM, PowerCom, or ZCOMM manual chapter "OPTIONS
FOR FILE TRANSFERS" for descriptions of the file transfer options. The
"FILE TRANSFER BASICS" chapter explains the relative merits of XMODEM,
YMODEM, ZMODEM, and other protocols and gives tips on their use. The
"MAIN COMMANDS" chapter describes the rb, rx, rc, rz, sb, and sz
commands. The "MODEM INTERFACING" and "FLOW CONTROL" chapters contain
important information on the use of buffered modems with DSZ.

Information on the ZMODEM Inter Application File Transfer Protocol is
available in Omen Technology's "ZMODEM DEVELOPER's COLLECTION" ($89.00).

Unix/Xenix C Source code for XMODEM, YMODEM, and ZMODEM transfers
to/from Omen Technology Products is included in RZSZ.ZOO.[1] This file
includes a Pro-YAM/ZCOMM script to upload a bootstrap file to a Unix
system, compile it, and (if the compilation is successful) upload the
rz/sz source files.


1. Technical support for rzsz is available on a paid consulting basis.

Chapter 16 Pg 47 DSZ Reference Rev May-3-92 Typeset 5-3-92


Some of the batch files mentioned in this document are not included in
the archives. Those that are needed can be readily created with your
favorite editor.

ZMODEMU.BAT constitute Omen Technology's DSZ.ZIP. These same files are
in DSZ.ZOO on the distribution diskette mailed to registered users.[1]

2S-PIF.DVP, 2A-PIF.DVP, DS.BAT, and 2T-PIF.DVP are used with Quarterdeck
Office Systems' DESQview multitasking executive for background
operation. Their use is described in a previous chapter of this

DGSZ.ZOO is distributed to GSZ registrants. It contains GSZ.EXE and
GCOLORS.EXE in addition to the above.

ZCOMMDOC.ZIP (manual), ZCOMMEXE.ZIP (programs), ZCOMMHLP.ZIP (help
processor and database), make up the ZCOMM communications tools
shareware distribution. The ZCOMM files are available on finer bulletin

RZSZ.ZOO contains ZMODEM "C" source code for COMPLETE Unix/Xenix
programs licensed for use transferring files to/from licensed Omen
Technology products.[2]

RZSZ.TLB The ZMODEM rz/sz programs are available in native VMS flavors
with wild cards, record format support, etc.. Pre compiled VAX/VMS
files are contained in the RZSZ.TLB compressed text library, available
in the TeleGodzilla upgrade/vms subdirectory, Compuserve VAXFORUM,
GEnie, and other bulletin boards.

DSZ.EXE compiled with the Xenix to DOS XC may give moderately higher
maximum throughput noticeable on slower machines. Sending from a faster
machine to an 8 MHz IBM AT with 16550FAN, using 115200 bps and "sz -yZ

Program Throughput


1. DSZ.ZOO is supplied to registrants instead of DSZ.ZIP because not
all registrants have copies of unarchiving programs. The
registration disk includes a copy of BOOZ, a simple dearchiver for
ZOO files.

2. Technical support for rzsz is available on a paid consulting basis.

Chapter 16 Pg 48 DSZ Reference Rev May-3-92 Typeset 5-3-92

DSZ.EXE 12735 cps
DSZ.COM 7164 cps

ProComm+2.0 5928 cps

(Compare these speeds to those listed on Page 159 of the April 30, 1991
issue of PC Magazine. Results are even better with the compressible
file used in the PC Magazine tests.)

DSZ.EXE supports ZMODEM over 7 bit paths (E and P options), and
specified control character quoting (-Q option). The DSZ.EXE
requires somewhat more memory than DSZ.COM. The maximum DSZ.EXE I/O
buffer size available with the B numeric parameter is 16384. DSZ.EXE is
available in DSZEXE.ZIP and DSZEXE.ZOO.

ZCOMM and Pro-YAM also run faster than DSZ.COM.

DSZBG.ZOO contains DSZBG.DOC. Part of the DSZ registration disk, this
file provides background information on the ZCOMM/Pro-YAM commands
provided in DSZ and GSZ.

The ZOO archive format is a machine independent improvement on the PC-
DOS specific .ARC format. The ZOO format has been precisely defined, and
stable ZOO archivers/dearchivers are available on a wide variety of

BOOZ.EXE unpacks .ZOO archives. BOOZ.DOC describes BOOZ.EXE.

Chapter 17 Pg 49 DSZ Reference Rev May-3-92 Typeset 5-3-92

17. Other Omen Technology Products

17.1 Professional-YAM COMMS TOOLS

Omen Technology makes Professional-YAM, a comprehensive comms program
with unmatched power. Flavors are available for PC-DOS, Unix, Xenix,
and OS/2 Protected mode. Unix source code is available under license.

17.2 ZCOMM: Industrial Strength COMMS Shareware

ZCOMM is a full featured shareware version with a $40.00 basic
registration. Registered DSZ users upgrading to ZCOMM get a free

17.3 ZMODEM Developer's Collection

Omen Technology sells the "ZMODEM Developer's Collection" for $89.00.
This diskette includes the most recent public domain versions of
YMODEM.DOC, ZMODEM.DOC and the Unix/VMS rz/sz C source code for YMODEM
and ZMODEM. Porting to the intended application is the sole
responsibility of the purchaser. For many developers, this collection
affords a significant labor savings in obtaining these materials.

Chapter 18 Pg 50 DSZ Reference Rev May-3-92 Typeset 5-3-92


Unlike snazzy menu interfaces, reliable high speed transfer protocols
take many hours of testing, often over expensive phone connections, to
develop. Two decades of communications experience and protocol testing
are distilled in DSZ.

DSZ is a user supported program developed and supported by Chuck
Forsberg, owner of Omen Technology. Countless hours of work and
expen$ive resources went to develop and support DSZ for the myriad
environments users use it in. The fact that most of the problems people
encounter with DSZ are caused by other software, hardware problems,
failure to read the supplied documentation, or pirating has not kept
users from seeking and getting help, even if it means calling the author
in the middle of his sleep.

Beyond this, the world of communications is constantly evolving, and it
requires a significant ongoing effort to keep DSZ and its documentation
up to date with the current state of the art. Individuals with little
knowledge of the dynamic nature of telecommunications (or hidden
agendas) have misrepresented the frequency of enhancements to DSZ as a
sign that DSZ is "unstable" and unworthy of "serious consideration". If
you think such sniping is fair play, you are more than welcome to use
one of the many other protocol programs available, each of which claim
to offer speed and reliability comparable to DSZ.

Non registered users are welcome to use DSZ for a reasonable evaluation
period. "Reasonable" means "until you've decided whether the program is
worth $20.00." It does not mean "until some competing program gets
around to adding ZMODEM or True Ymodem(TM)". Once you've evaluated DSZ,
ethical use of DSZ requires registering the copy.

DSZ is not and never has been Public Domain. Every version of DSZ has
included a Copyright Notice and a prohibition against sale or
modification. There is no usage counter or other Trojan Horse in DSZ,
but if you use this program, you have a moral and ethical obligation to
register it.

Paid registration enables t -8g, DIRRX, DSZOPT, OverThruster(TM),
YMODEM-g, and other advanced features that are present in DSZ.ZIP in
encrypted form. The registration package serializes and decodes all
past and future versions of DSZ.COM and DSZ.EXE. You can get a fully
featured upgrade of DSZ simply by downloading a newer version from
TeleGodzilla, BIX, GEnie (IBM Roundtable), CompuServe, and trusted
bulletin boards.

Chapter 18 Pg 51 DSZ Reference Rev May-3-92 Typeset 5-3-92

18.1 Sharing DSZ Files

You are welcome to share unmodified copies of DSZ.ZIP or DSZ.ZOO with
your friends and associates for their evaluation. This documentation
file and the MAILER file must be provided with all copies of DSZ except
by prior written permission from Omen Technology Inc. Because of piracy
problems, Omen Technology must INSIST that DSZ be distributed only as
part of the DSZ.ZIP file EXACTLY as provided by Omen Technology Inc, or
in an archive which displays a CRC value for DSZ.COM equal to that shown
in the Changes chapter. If DSZ.ZIP is repacked, no files may be added
to or removed from the archive.

If you see an improperly packed or otherwise modified DSZ archive or
parts thereof in a bulletin board, please ask the board's operator to
replace such files with DSZ.ZIP exactly as provided by Omen Technology
Inc. Flame them until they behave ethically.

Unmodified copies of Omen Technology shareware and demo files including
GSZ.ZIP, DSZ.ZIP and DSZBG.ZIP may be distributed by "shareware
distributors" provided 1) the files are clearly identified as
unregistered shareware, 2) the cost of the distribution is nominal.
Otherise, no version of DSZ may be sold without the prior written
permission of Omen Technology Inc.

DSZ is not and never has been Copy Protected. "DSZ unprotect" files
have no function whatsoever except to aid and encourage the theft of
Omen Technology's Intellectual Property.

Distribution or use of programs or procedures that modify, patch,
disassemble, decompile, or otherwise reverse engineer DSZ without the
prior written permission by Omen Technology Inc is a bloody theft of
intellectual property and services and is a violation of Federal
Copyright Law. The same applies to debug scripts and documentation
written for the same purposes. These perform the same function as
pirate satellite and/or cable descramblers, to obtain benefit from
encrypted communications without proper payment. Piracy has been
investigated by the FBI and prosecuted under federal statutes.
Applicable law provides for damages and recovery of attorney's fees.
Omen Technology has received reports of serious problems caused by
unauthorized patches to DSZ, and cannot assume liability for the
performance of the resultant code. So far, none of the slime producing
such bilge have seen fit to sign their real name and address to their
cretinous attempts at ego gratification.

Distribution of DSZ in any medium without this documentation file is an
unauthorized modification to DSZ that deprives the rightful author of
registration revenues. That is a theft of intellectual property. Such
distribution damages the author by forcing the user and author to waste
time and phone bills scrounging for the documentation, and answering
questions that are fully covered in the documentation.

Chapter 18 Pg 52 DSZ Reference Rev May-3-92 Typeset 5-3-92

If any version of DSZ is distributed with any other product, software or
hardware, the product documentation must clearly and prominently state
that the customer's continued use of DSZ requires registration directly
with Omen Technology or its duly authorized agent(s). When unregistered
copies of DSZ are distributed on disk, a contemporary copy of
ZCOMMDOC.ZIP should be included on the same disk.

Thank you for your support.


After a short evaluation period, ethical users must register their copy
of DSZ with a check for $20.00 in U.S. funds sent to:

Omen Technology Inc.
P.O. Box 4681
Portland, OR 97208

The address on your check is sufficient, no need to fill out forms.

For VISA/MC Registrations, you can also:
Call VOICE: 503-621-3406

Or register online: 503-621-3746 300-1200-2400 bps
Or FAX the INSTANT MAILER to: 503-621-3735

Don't bother scrounging for an envelope, just print the INSTANT MAILER
included in this archive!

Overseas registrations are sent out International Air Mail. Users,
especially those overseas, may choose to register their copy of DSZ for
$25.00 U.S. by providing their VISA or Mastercard card number with
expiration date and their name as it appears on their credit card.

Purchase orders for less than $150 must be prepaid. Omen Technology Inc
Federal TAX ID #: 930858776 Oregon TAX ID #: 536565
.ne 12

"Das Recht zur Benutzung von DSZ in Deutschland, Oesterreich und der
Schweiz erwerben Sie durch Bezahlung der Lizenzgebuehr von DM 57,00
(incl. Mwst) an RzK

Doris Koepke
Bitzenstr. 11
D-5464 Asbach

Tel. 02683-4547, FAX 49 2683 4537, Telex 86 3705 rzk d, CIS
[70126,1660]. Sie erhalten dann von dort sowohl die neueste Version, als
auch Ihren individuellen Software-Key, mit dem Sie auch kuenftige
Shareware-Versionen "aufschliessen", also die in der Shareware Version
nicht zugnglichen Programmfunktionen nutzbar machen koennen, per Post.

Chapter 18 Pg 53 DSZ Reference Rev May-3-92 Typeset 5-3-92

Die Benutzung nicht registrierter Versionen stellt einen Verstoss
geltenden Rechts dar und wird strafrechtlich verfolgt."

The user registration package includes a printed serial number password
(SNP) card. The registration "care package" diskette contains the
latest versions of the DSZ programs, additional user documentation, and
the installation program which uses your personal SNP to enable advanced
features and bypass the opening advertisement.

The registration package unlocks the extra value in all past and future
versions of DSZ.COM and DSZ.EXE.

The unique serial number on the registration card is registered to the
user, and is acceptable proof of registration to corporate auditors.

The putsnp program inserts your unique DSZ Serial Number Password (SNP)
into you copy of DSZ with the following command:
Putsnp prompts for your SNP and asks appropriate questions before
inserting the SNP to enable the extra value in DSZ.

GSZ is serialized with the GCOLORS program described above.

Some TSR programs and device deivers interfere with putsnp. If you have
a lockup running putsnp, run it without any device drivers or TSR
programs (boot a plain DOS from floppy disk).

Your disk directory entry for DSZ will show the date and time you
serialized your copy of DSZ. This does not affect the revision date DSZ
announces when DSZ is run.

The only legitimate way to disable the opening advertisement in DSZ is
to insert an authorized SNP obtained from Omen Technology into DSZ with
the putsnp program. Any other suppression or modification of the
opening screen is an illegal, unethical theft of services. Omen
Technology has received reports of serious problems caused by
unauthorized patches to DSZ, and cannot assume liability for the
performance of the resultant code.

Piracy is stealing.

Chapter 18 Pg 54 DSZ Reference Rev May-3-92 Typeset 5-3-92

18.3 Files on Registration Disk

The following files are currently included on the Registration Disk sent
to paid registrants.

BOOZ.EXE Program to unpack .ZOO archives. BOOZ.DOC describes


To dearchive with booz: booz x dszexe

Type "booz" without arguments to see the help message.

DSZ.ZOO Contains DSZ.COM, DSZ.DOC, DESQview description files.

To dearchive with booz: booz x dsz

DGSZ.ZOO Contains GSZ, DSZ, GSZ.DOC, and DESQview description

To dearchive with booz: booz x dsz

RZSZ.ZOO contains ZMODEM "C" source code for COMPLETE VAX
VMS and Unix/Xenix programs licensed for use transferring
files to/from licensed Omen Technology products.[1]

To dearchive RZSZ with booz: booz x rzsz

PUTSNP.EXE Installs your unique registered serial number to enable
the extra value in DSZ. (GCOLORS is used for GSZ.)

DSZBG.DOC (in DSZBG.ZOO) Background information for GSZ and DSZ,
consisting of relevant parts of the ZCOMM User's Manual.

To dearchive with booz: booz x dszbg


1. Technical support for rzsz is available on a paid consulting basis.

Chapter 18 Pg 55 DSZ Reference Rev May-3-92 Typeset 5-3-92

18.4 Bulletin Board Registration

Note to the wise BBS operator: be sure you understand the DSZ restrict
command and how to use it.

Use and/or copying of DSZ by bulletin board sysops and/or systems is
allowed according to the following conditions:

I agree to feature the ZCOMM files (ZCOMMEXE.ZIP, ZCOMMDOC.ZIP,
ZCOMMHLP.ZIP) for downloading, and to announce the availability and
features of ZCOMM in any bulletins, help displays, or other displays
that mention communications programs. It is my responsibility to
maintain reasonably current versions of the ZCOMM files on the BBS shown

I understand that I am welcome to use DSZ on my bulletin board(s) from
the time I sign and mail this document as long as I abide by the
conditions above, including featuring the above mentioned ZCOMM files.

I shall distribute DSZ.COM only as part of the DSZ.ZIP EXACTLY as
provided by Omen Technology Inc, or "zipped" without any file additions,
deletions, or modifications. If I distribute DSZEXE.ZOO, I shall also
maintain DSZ.ZIP in the same directory since DSZEXE.ZOO references files

If I see a modified DSZ archive or parts thereof in a file or collection
of files (e.g., archive) on a bulletin board, I shall replace such files
or archive members with the contents of DSZ.ZIP exactly as provided by
Omen Technology Inc. I shall report instances of noncompliance to Omen

I shall not allow any version of dsz to be sold, modified, patched,
hacked, disassembled, decompiled, or otherwise reverse engineered
without the prior written permission of Omen Technology Inc.

I understand that DSZ is not and never has been Copy Protected. I fully
understand that "DSZ unprotect" files have no function whatsoever except
to aid and encourage the theft of Omen Technology's Intellectual

(For this BBS registration, a multi node bulletin board operating from a
single, common file system counts as one machine.)

The purpose of bulletin board registrations is to support and promote
ZCOMM and Professional-YAM by popularizing the ZMODEM protocol and
featuring the ZCOMM shareware files available for downloading.

BBS registrations must be submitted on the bbs_reg form with signature
and date, and must accompany a new paid DSZ or ZCOMM registration. The
paid registration that must accompany your BBS registration can be one
submitted by one of your board's users. Most boards have many

Chapter 18 Pg 56 DSZ Reference Rev May-3-92 Typeset 5-3-92

unregistered DSZ users, so getting one of them to register their DSZ
should pose no difficulty. Since the paid registration may be from one
of your board's users, you can get your BBS registered for free by
getting one of your users to register his/her DSZ at the same time.

Chapter 18 Pg 57 DSZ Reference Rev May-3-92 Typeset 5-3-92


Be sure to save your serial number/password (SNP) card and the putsnp
program you received from Omen Technology to use with future versions of
DSZ you may download! (Use GCOLORS to serialize GSZ.)

Current GSZ and DSZ versions are maintained on EXEC-PC BBS, BIX, GEnie
(IBM Roundtable), CompuServe (IBMCOM and CONSULT SIGs) as well as

DSZ is a popular program which has been the object of virus attacks.
Pirated/hacked versions of DSZ have cost users and DSZ's developer
thousands of dollars in lost time and other expenses, in addition to
injuring of Omen Technology's reputation.

Virus and Trojan code hidden in hacked/pirated copies of DSZ and
programs claiming to "register DSZ" have caused loss of data.

Name Length Date Time CRC

-rw-r--r-- 1 caf omen 52586 May 03 15:22
-rwxr-xr-x 1 caf omen 60251 May 03 15:25 dsz.exe
PKZIP -vt 32 bit CRC: 0B00125F 52586
PKZIP -vt 32 bit CRC: BF552B2D 60251 dsz.exe

Your copy of DSZ should show the same CRC values. ZIP uses a 32 bit CRC
compatible with the Professional-YAM and ZCOMM "crc" command.
pkzip -vt dsz
The following Pro-YAM/ZCOMM command gives the 32 bit CRC for DSZ.COM:

EXAMPLE: >>>c: crc

If your copy shows a different CRC or file length, insist on a
legitimate copy and report the source of the bogus/pirated copy to Omen
Technology Inc. Omen Technology has received reports of serious
problems caused by unauthorized patches to DSZ, and cannot assume
liability for the performance of the resultant code.

COM7 and COM8 are changed; see the "port" command above.

A problem in the 1/17/89 and 2/2/89 DSZ versions corrupts files under
unusual circumstances. Please delete all instances of the 1/17/89 and
2-02-89 version.

There never was a "zmodem d" parameter in DSZ. Older versions of DSZ
ignored attempts to set this nonexistient parameter with a message that

Chapter 19 Pg 58 DSZ Reference Rev May-3-92 Typeset 5-3-92

humans ignored. DSZ now aborts when asked to set a nonexistient
parameter. There is a "d" parameter that controls time/date stamping of
files; Bulletin boards that need to disable time/date stamping of
received files should simply use "pd0" not preceded by a "z".

Good news for tired frog stompers! The ZMODEM rz/sz programs are
available in native VMS flavors with wild cards, record format support,
etc.. Pre compiled VAX/VMS files are contained in the RZSZ.TLB
compressed text library, available in the TeleGodzilla upgrade/vms
subdirectory, Compuserve VAXFORUM, GEnie, and other bulletin boards.

The DSZ and GSZ "t" command uses the DOS console driver for terminal
emulation. Standard ANSI.SYS is limited to a small subset of ANSI
escape sequences; NANSI.SYS, FANSI-Console and other replacement console
drivers provide faster screen updates and better ANSI terminal

DESQview users: make sure "Separate Shift State" is set to "N". (Tnx to
Tim Trott for this info.)

May 3 1992: Recompiled to correct bad file size/CRC values in DSZ.DOC
and DSZNEW, pruned some unused code. No functional changes from April
27 vsn.

April 27 1992: The GSZWINDOW environment variable can be set to 1, 2 or
3 to leave the top 1, 2 or 3 lines unmolested. DSZ.EXE is compiled on a
newer compiler and now supports file sharing.

Bogus/hacked/infected files with early 1992 revision dates have been

Dec 13 1991: DSZ and GSZ automatically support Doorway 2.2 without extra

The RZ.BAT and SZ.BAT files are supplied for convenience. RZ.BAT allows
calling programs that emit an "rz" command to automatically start DSZ
from the DOS command prompt. SZ.BAT is a convenient command interface
that complements RZ.BAT. You may modify SZ.BAT and RZ.BAT with your
favorite options.

The GSZ file transfer display now shows a distinct color at the
locations where error retries occurred. This gives a visual impression

of the distribution of error retries.

Oct 15 1991: To accomodate other vendors' programs which do not provide
a convenient way to control crash recovery, the "restrict" command
security check is not performed if the destination file does not exist.

Oct 8 1991: Some versions of putsnp were confused by a data pattern in
the Oct 7, misplacing the installed serial number. Oct 7 1991:
The "t" (talk) command now accepts -h and -H to enable local echo. Oct

Chapter 19 Pg 59 DSZ Reference Rev May-3-92 Typeset 5-3-92

1 1991: Fixed an interaction between FIFO uarts and YMODEM-g termination
after all files have been sent. Fixed problem of some options being
ignored on XMODEM and YMODEM downloads. Fixed graphics display problem
involving more than 40 MB of files. Sep 4 1991: GCOLORS now saves the
color scheme in a separate file GCOLORS.T. Many small improvements in
the GSZ file xfer display. GCOLORS adds a "m" menu choice to remove
color from the color scheme.

A conflict between crash recovery and user specified short packets has
been corrected.

DSZ.EXE and GSZ now accept the "c" option to force incoming files to use
a changed file name when a file with the same name exists. The
receiving program must support this new ZMODEM option or file
disposition will be undefined.

Aug 7 1991: Serial I/O modifications have solved a Wedge-O-Matic(R)
problem with one hardware configuration (antique 2400 bps internal
modem). Hopefully this will solve similar non-replicatable problems for
other users.

A number of display fixes/enhancements to GSZ, including the addition of
the GSZWINDOW environment variable enabling BBS sysops to protect BBS
status lines at the bottom of the screen.

July 29 1991: Corrections to gcolors registration function.

July 28 1991: Some changes to GSZ and CGOLORS to improve human factors.

"GCOLORS -q" disables the flashing reminder of which field is being
modified. This was added to help users with certain visual impairments.

A few users have reported hung transfers wither certain hardware and/or
software configurations. We have not been able to replicate the
problem, but have added code that recovers from lost interrupts.

July 21 1991: Preview release of GSZ!!

July 3 1991: Spurious "Invalid Download Directory" message has been
removed. More hacks to accomodate AT&T's mutant "ymodemb" protocol.
AT&T may be the right choice, but their "ymodemb" is not the right

June 13 1991: DSZLOG entries made by the 6/10 DSZ had no carriage
returns. Please check the "pxN" and "z pxN" command descriptions for
important clarifications.

June 10 1991: A problem with sending with flow control has been fixed.
Intelligent Crash Recovery(TM) has been enhanced to prevent timeouts

Chapter 19 Pg 60 DSZ Reference Rev May-3-92 Typeset 5-3-92

when computers with different CPU speeds are used.

May 31 1991: The "sb" command has been hacked to accomodate an AT&T
nonstandard "ymodemb" protocol.

The handling of hardware flow control has been hacked to prevent flow
control timeouts caused by TSR programs that poll the UART status

The size of the input buffer has been increased.

The "V" numeric parameter has been added to DSZ.COM to allow direct
video output in some instances.

April 29 1991: The "t" command no longer ignores options set with DSZOPT
and/or as flags to the "t" command.

April 16 1991: Operation of "handshake slow" has been enhanced when
receiving with ZMODEM CRC-32 and MobyTurbo(TM). Users who had
previously found "handshake slow" unable to control disk related "Line
Status Register 02" overrun errors should find the new "handshake slow"
more effective on ZMODEM CRC-32 and MobyTurbo downloads.

DSZ.COM and DSZ.EXE now announce themselves as DSZ.COM and DSZ.EXE.
DSZ.DOC has more discussion of differences between .COM and .EXE flavor.
See the FILES chapter for expanded discussion of DSZ.COM vs DSZ.EXE.

April 4 1991: DSZ now supports 115200 bps on suitable hardware.
DSZ.EXE throughputs of 113000 bps have been achieved with modest
trickery. "Your mileage may vary."

The -I option has been added to the sz command. The -I option causes
new versions (Mar 29 1991 or later) of VMS rz to store files with the
VMS Variable length (mrs=510) binary format. Adding this record format
should prevent VMS Kermit servers from corrupting file contents.

pcAnywhere users: please read the "A" command description carefully!

Feb 28 1991: The instructions for adding DSZ to ProComm Plus have been
updated to include PCP version 2. Datastorm has not licensed ZMODEM-
90(TM) despite allegations that DSZ is now "built in" to ProComm Plus
version 2.

The F command was added to leave the 16550A FIFO enabled on exit. The
speed command now updates the effective baudrate used for time

sz -e is more network friendly. (If you don't know what sz -e does, you
don't want to know - trust me.)

Chapter 19 Pg 61 DSZ Reference Rev May-3-92 Typeset 5-3-92

Dec 16 1990: Code changes to improve operation with the Intel
SatisFAXtion modem/fax board.

Nov 19 1990: A number of small enhancements.

The sz -i and -u options were added. The -i option is useful sending
files to VMS rz version 4.x, forcing VMS Stream_LF record format. The
-u option unlinks (deletes) a file after it is successfully sent with

SlugBait has been fixed.

The Y numeric parameter (described above) has been added to allow FIFO
hackers to do their thing.

June 25 1990: When a ZMODEM block length is forced, the receiving DSZ
writes the data to disk before acknowledging the block. With DSZ.EXE
and its maximum 16384 buffer size, you may be able to avoid overrun
(Line Status Register 02) problems receiving to slow disk drives by
DSZ pB16384 z pl16384 rz

ZMODEM-90(TM) speeds up GEnie ZMODEM downloads; see DSZOPT.

The "sz" command had an undocumented fallback to YMODEM, this has been
removed for reliability reasons.

The SlugBait (-s) option now causes DSZ to return success (0 exit code)
if at least one file is transferred.

April 11 1990: Enhancements for more efficient multitasking under
DESQview and DESQview 386. Code which prevented IRQ conflicts between
COM1/COM3 and COM2/COM4 has been removed to allow use of COM7 and COM8
without interference from DSZ running on COM1 or COM2..

ZIP replaces ARC as the standard download distribution format on new

March 21 1990: DSZ now sends the CANCEL sequence if it runs out of disk
space while receiving a file with ZMODEM.

DSZ now defaults to "handshake both" if the clear to send signal is high
when DSZ selects the comm port regardless of the initial "baud rate".

The P parameter can be set to -1 to disable the FIFO on the Western
Digital WD16550 chip. The WD16550 FIFO has been observed to lose
characters when transmitting at slow baud rates. A more elegant
software solution to this hardware problem may be discovered in the

Feb 25 1990: Doco change only. The "R" numeric parameter or the

Chapter 19 Pg 62 DSZ Reference Rev May-3-92 Typeset 5-3-92

"restrict" command may be used to force partially received files to be
deleted. These features have been in DSZ for a long time, but never got
into DSZ.DOC.

Feb 18 1990: DSZPORT now accepts "portx" style arguments in addition to
the traditional decimal number. The -Wn option has been improved.

Jan-28-1990: Doco improvements, especially to the "In Case of
Difficulty" chapter. BBS registration clarified for those that bother
to read it. Qmodem batch files fixed. No change to the DSZ software.

Jan-22-1990: ZMODEM-90(TM) extensions:

Receiver specified window size: The -Wn option operates similarly to the
-wn option. The -Wn option is specified to the receiver, which sends
this information to the sender. Pro-YAM, ZCOMM and DSZ versions
beginning with Jan 22 1990 support this.

Specified extra escaped characters: The "zmtxesc" and "zmrxesc" allow
extra characters to be escaped when sending (zmtxesc) or receiving
(zmrxesc). Zmtxesc is effective sending to any ZMODEM program. The sz
commands in Omen products after Jan 22 1990 except for DSZ.COM recognize
incoming "zmrxesc" requests. The zmrxesc and zmtxesc string parameters
consist of one or more printing characters corresponding to the control
characters to be escaped. To escape NULL: set zmrxesc "@"

Since DSZ does not support string parameters, a -Q option unique
to DSZ performs the same function as zmrxesc and zmtxesc. If the
Q option is used in DSZOPT, it must be last. To escape NULL:
DSZ sz -Q@ file.ext


MobyTurbo optimizes throughput on GIF, ZIP, ARC, and similar files
without sacrificing ZMODEM's famous reliability on noisy lines.
MobyTurbo works with standard modems, error correcting modems with
hardware flow control, and over paths that support ZMODEM and do not
"eat" or otherwise respond to control characters. This includes all
paths that support YMODEM-g (or would except for line noise).

MobyTurbo can be used for downloads over PC Pursuit if software flow
control is not turned on.

Activate MobyTurbo with the -m option to one or more of: sz command, rz
command, or DSZOPT environment variable.

ZMODEM over 7 bit paths: (Not supported in DSZ.COM)

A pair of ZMODEM-90 programs with 7-bit support operating over a 7 bit
path should detect that fact and switch to one of two 7-bit path
compatible encodings. For testing, this can be forced with a "-E"

Chapter 19 Pg 63 DSZ Reference Rev May-3-92 Typeset 5-3-92


Default 7-bit mode is RLE compression and 8th bit quoting similar to
Kermit but more efficient because not so many control characters are
quoted. Use this default for text files. Rubout and all control
characters can be escaped with the -e option. Individual control
characters can be escaped with "zmtxesc" and "zmrxesc".

Pack-7 instead of quoting is activated with the -P option. (-P has no
effect on 8 bit paths.) Pack-7 packs 4 bytes into 5 printing characters.
This is more efficient than quoting for files where 25% more 8th bits
appear than the number of characters saved by RLE compression. (This
statement applies to GIF, ARC, ZOO, and ZIP files. It may or may not
apply to other binary file formats, depending on the data.) Pack-7 will
match or beat standard Kermit on ZIP files, even when Kermit has use of
all 8 bits.

SUPK412.ZIP 75136 bytes sent at 2400 bps direct connect from an
Everec 1800 AT clone 8mHz/0ws to an 18 mHz Intel 386 motherboard.

8-Bit line
cps Protocol/command
156 MS Kermit 3.00 to MS Kermit 3.00 (defaults)
182 MS Kermit 3.00 to MS Kermit 3.00 (windows=2 length=2000)
184 MS Kermit 3.00 to Pro-YAM 17.51 (windows=2 length=2000)
231 Pro-YAM 17.51 ZMODEM (defaults)
237 Pro-YAM 17.51 ZMODEM-90(TM) MobyTurbo(TM) (sz -m)

7-Bit line
cps Protocol/command
156 MS Kermit 3.00 to MS Kermit 3.00 (windows=4 length=2000)
190 Pro-YAM 17.51 ZMODEM-90 PACK-7 (sz -EP)

Kermit transfers used 8 bit CRC, ZMODEM used 32 bit CRC.



Performance difference with MobyTurbo, possible side
effects/incompatibilities. MobyTurbo logic tests for software flow
control incompatibilities: when does this test fail?

Automatic detection of 7-bit paths. Spurious detection of 7-bit paths
and failure to detect 7-bit paths. (DSZ.EXE only)

12-13-89 The Virus check was removed because of user confusion and slow
startup under certain conditions. Code has been added to prevent and/or

Chapter 19 Pg 64 DSZ Reference Rev May-3-92 Typeset 5-3-92

recover from "line status register 18" errors.

10-28-89 A T may be appended to DSZOPT or "DSZ t -T" may be used to
force DSZ to exit after it has recognized a ZMODEM AutoDownload(TM)

10-24-89 BBS registered copies (serial numbers 8000-8999 and 20000-
23999) are now fully featured.

The BBS registration form has been modified. Please read this form
carefully before applying a BBS serial number. Use of BBS serial
numbers (4000, 20000 series) acknowledges acceptance of this contract.

The IMP/KMD compatibility file length information in the YMODEM header
generated by the sb command now uses the correct byte ordering. Changes
to the XMODEM/YMODEM sz/sb commands were made to accommodate programs
that ise CK or CKL. (As predicted in 1985, networks sometimes interfere
with these sequences.)

Files passed over because of creation errors at the receiving end are
now counted by the "sz" command as errors. The receiving program must
be a 9/89 or later version for this to be effective.

The specified directory form of the rz and rb commands has been enanced
to accommodate certain forms of erroneous syntax.

6-19-89 A documentation error (concerning DSZPORT) was corrected in the
DOC file.

5-25-89 Corrects a protocol negotiation problem encountered when the rz
or sz -e option is used.

Host programs can now specify an alternate CANCEL sequence (not used for
DOS and Unix).

The ZMODEM "Slow Send" mode inserts a brief pause after each subpacket
when invoked with the -F option, or automatically when the "sz" command
detects failing flow control. The zmodem F numeric parameter (default
1) sets the pause in tenths of seconds.

4-24-89 The -rr option has been improved. Long file compares are done
in two stages to save time when the first portions do not match.
Diagnostic code and undocumented commands have been removed to decrease
the program size.

The 4-18 version introduces ZMODEM variable length headers of up to 16
bytes information field instead of the previous fixed 4. Selection of
variable length header capability is automatic and downward compatible.
Variable length headers allow future extensions to ZMODEM's

Chapter 19 Pg 65 DSZ Reference Rev May-3-92 Typeset 5-3-92

ZMODEM Crash Recovery now understands the -rr option to compare the
CRC-32 of the assumed common file segment before continuing an
incomplete file transfer. The "zmodem R" numeric parameter may be set
to limit the number of bytes in the files that are compared; the default
R value of 0 allows all of the file to be compared, an R value up to
32000 (up to 2 billion on 32 bit flavors) limits the comparison to the
first R bytes of the two files. The ZMODEM -rr option is supported by
Omen Tech versions April 18 1989 and later.

When ZMODEM Crash Recovery detects incompatible source and destination
file contents, the destination file is now truncated to zero length
before proceeding with the transfer. Crash Recovery requires the
destination file to be no longer than the source file.

Error reporting on unregistered copies has been enhanced to point the
user to solutions described in the relevant chapters in DSZ.DOC.

3-18-89 In order to work around a bug in the new TCOMM bbs, DSZ now
defaults to "handshake on" if the speed is greater than 2400 and the
clear to send signal is high when DSZ selects the comm port.

The "o" command has been added to disconnect the modem after a terminal
session: "DSZ t o" disconnects the modem when the terminal session is

The "P" (capital P) numeric parameter (q.v.) has been added to display
and control the UART fifo on some clone chips.

BBS registrations postmarked after Feb 28 1989 must be accompanied by a
paid DSZ registration. The free program expired Feb 28 1989. Outside
help has been hired to process and verify applications received under
that program.

2-23-89 The term function now sends BREAK in response to the ALT-B key.
Handling of the Ctrl-Break vector has been changed so an untimely
keyboarded Ctrl-C or Ctrl-Break will not hang DOS.

2-15-89 DIRRX is enabled for BBS registrations (8xxx numbers). Logic
has been added to simulate transmit interrupts on chips that have
problems in this area. The "A" command does not require registration.
An interaction between ONAME= or PREFIX= and the file count display has
been removed. Time/date conversion routines have been enhanced to deal
with files with missing dates. The "v" command has been added to allow
bbs programs to interrogate DSZ's serial number.

2-06-89 A spurious error message at the completion of YMODEM downloads
with a download directory specified on the command line has been

2-05-89 DSZ now returns a non 0 status unless at least one file has been
transferred. An inappropriate pathname/disk specifier check on

Chapter 19 Pg 66 DSZ Reference Rev May-3-92 Typeset 5-3-92

specified download directories has been removed.

Previous versions:

Added the "A" command to prevent pcAnywhere host mode from locking up
DSZ. SlugBait logic has been simplified, reporting any failed file
transfer where any of the last 1K of the file was sent with Q status.

Introduced ZMODEM RLE compression with the -Z option. (registered DSZ
copies also accept "Z" in the DSZOPT environment variable.) ZMODEM RLE
compression packs runs of the same character in two or three character
sequences. Compression is useful for screen dumps, uncompressed
workspaces, compiler listings, and other files rich with strings of
repeated characters, but not .GIF, .ARC, .ZOO and other compressed
files. Compression percentages range from -1 per cent for already
compressed files to more than 1000 per cent (10x speedup!) for the
Personal Computing text file benchmark(!). When sending to programs
that do not support ZMODEM compression, the -Z option is ignored. The
-Z option is effective when specified to the sending program only.

"Handshake slow" has been added to disable the RTS signal to the modem
while writing to disk, even if the interrupt buffer is not chock full of
bytes. This should help systems with excessive interrupt latency on
disk writes.

Setting the v (verbose) parameter to 1 or greater causes serialized
copies to ring the bell when a transfer is done.

DSZ.DOC has been extensively rewritten and reorganized. DSZ supports
the advanced buffering of the National NS16550AN, NS16550AFN and Intel
82510 serial interface devices. Please refer to the subchapter on
"Brain Damaged UARTs".

Chapter 20 Pg 67 DSZ Reference Rev May-3-92 Typeset 5-3-92


32 bit CRC code courtesy Gary S. Brown.

ZMODEM-90(TM), MobyTurbo(TM), The High Reliability Software(TM), Demand
Upgrade(TM), TurboLearn Script Writer(TM), Cybernetic Data Recovery(TM),
ZMODEM AutoDownload(TM), Intelligent Crash Recovery(TM), Error
Containment(TM), Full Time Capture(TM), True YMODEM(TM),
OverThruster(TM), Password Guardian(TM), CryptoScript(TM), and
TurboDial(TM) are Omen Technology trademarks.

PowerCom was trademarked in 1985 by POLYTRON Corporation, Hillsboro

True YMODEM(TM) is an Omen Technology Trademark signifying YMODEM
protocol support that meets the full YMODEM specification.

DSZ and this documentation are Copyright 1991 by Omen Technology Inc,
all rights reserved. DSZ is not and never has been Public Domain.
Every version of DSZ has included a Copyright Notice and a prohibition
against sale or modification. This prohibition applies to any theft of
the intellectual property and trade secrets contained in DSZ by
decompilation, disassembly, or any other form of reverse engineering
including but not limited to profiling, tracing, data analysis, or
monitoring the operation of DSZ.

Omen Technology copyright applies to its expression of the encoding and
compression ideas expressed as code and byte streams used in the
ZMODEM-90 enhancements.

DSZ is not and never has been Copy Protected. "DSZ unprotect" files
have no function whatsoever except to aid and encourage the theft of
Omen Technology's Intellectual Property.

Omen Technology Incorporated
The High Reliability Software

17505-V Northwest Sauvie Island Road
Portland Oregon 97231
Modem: 503-621-3746 Speed 1200,2400,V.32
FAX: 503-621-3735
CompuServe:70007,2304 GEnie:CAF BIX:cforsberg

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