Dec 312017
 
VT220 emulator with file transfer (1 of 3).
File VTRANS.ZIP from The Programmer’s Corner in
Category Communications
VT220 emulator with file transfer (1 of 3).
File Name File Size Zip Size Zip Type
ASCTEXT.DOC 13212 3677 deflated
C7MAKE.FIL 140 98 deflated
C7UNIX.C 49872 13540 deflated
C7UNIX.H 2551 1076 deflated
C8MAKE.FIL 140 98 deflated
C8UNIX.C 46020 12481 deflated
C8UNIX.H 2777 1179 deflated
F7VMS.DEC 3668 1291 deflated
F7VMS.FOR 51985 11996 deflated
F8VMS.DEC 3302 1238 deflated
F8VMS.FOR 43887 11299 deflated
INTRO.DOC 10039 3758 deflated
KERCOM.DOC 14192 4398 deflated
KERMIT.DOC 16889 4853 deflated
VTRANS.DOC 16334 5528 deflated
XMODEM.DOC 10422 2562 deflated

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Contents of the ASCTEXT.DOC file


CHAPTER 17 ASCII TEXT (PROTOCOL-FREE) FILE TRANSFER

ASCII Text file transfer is a way of sending and receiving data
which -- unlike VTERM's other methods -- requires no special
software on the host computer. It's the fastest method of
transfer because no extra header or trailer characters are added
to the data.

On the other hand, there is no automatic error-correction with
ASCII Text transfer, so transmission over noisy communications
lines may corrupt data. And furthermore, only printable text
data may be transferred using ASCII Text transfer. Eight-bit
data, compiled programs, and some control characters cannot be
exchanged with this method.

Some communications programs (Smartcom IITM from Hayes, for
example) support a transfer protocol which their manufacturers
call "Stop/Start" protocol. This is nothing more than ASCII Text
transfer with XON/XOFF enabled. To accomplish the same thing
with VTERM, set Auto XON/XOFF on Setup Screen One to a value (64
to 512) and use ASCII Text transfer.

Before you use ASCII Text transfer for the first time, you should
read the section called "How To Transfer Files" in INTRO.XFR.

Logging and Printing Data with ASCII Text Transfer

ASCII Text transfer can be used to capture any text data from the
host, not just files, and place it in a disk file. When used in
this way, ASCII Text transfer accomplishes pretty much the same
thing as logging text with Ctrl-PrtSc or Alt-N.

ASCII Text transfer and Ctrl-PrtSc, however, always display data
on the screen as they print it or write it in a file. Alt-N
prints or writes data to disk without displaying it on the
screen.

You can use ASCII Text transfer and one of the logging methods at
the same time. This allows you to print text data from the host
and simultaneously put it in a disk file.


HOW TO RECEIVE FILES USING ASCII TEXT TRANSFER

To capture a file on the PC using ASCII Text transfer, you
complete the following steps:

1. Type (but do not press Enter) a host computer command that
causes the host file to be displayed on the terminal screen.
For example, on some DEC operating systems you can type TYPE
or PIP .

2. Before pressing Enter to execute the command, press Alt-R.

3. Complete the fields in the File Transfer Window as described
below. You complete the fields in the window by toggling
with the Plus (+) key or by typing as appropriate.

4. Press Alt-R again to start the transfer and press the Enter
key to execute the command you typed in Step 1.

To cancel the transfer, press the Esc key before pressing
Alt-R the second time.

When you press Alt-R the second time, the file transfer
status line is displayed. As data is received by VTERM, the
Bytes field on the status line displays the number of characters
received so far.

If you have entered a Stop upon receiving string on Setup Screen
Two, VTERM stops capturing data when this string is received and
closes the PC file. The status line then displays "Transfer
Complete."

If you have not entered the terminating string, or if you want to
end the capturing of data prematurely, press Alt-A. On Alt-A,
VTERM stops capturing the incoming data, closes the file, and
displays "Transfer Aborted" on the status line.

You can also terminate file transfer by pressing Alt-S (to
display Setup Screen One) or the hot key (to enter DOS).
After the transfer is finished, pressing any key causes the
terminal status line to reappear.

_______________________________________________________
| |
| Filename: \REP\BARB.TXT |
| Protocol: ASCII TEXT |
| |
| If File Exists: PROMPT |
| Ctrl-Z Marks End: NO |
| Translate: OFF |
| Remove Characters: |
|_______________________________________________________|
Arrow keys select, + changes. Alt-R=Receive,Esc=Cancel

Figure 17-1. File Transfer Window for Receiving
ASCII Text Files.

When you press Alt-R the first time, the File Transfer Window,
shown in Figure 17-1, appears on the terminal screen. You
complete the fields in window by toggling with the Plus (+) key
or by typing, just as on the setup screens. The fields are
described below.

Filename: Type the name that you want to give the received file
on the PC. Any valid DOS drive specifier and filename
may be used, including subdirectories.

Protocol: Toggle this field until ASCII TEXT appears.

If File Exists: This field determines what VTERM does if a file
already exists on the PC with the same name as
the received file. You choose one of the following:

OVERWRITE, VTERM erases the old file while
writing the new one to disk.

RENAME, the new file is renamed to avoid
overwriting the old file. (VTERM renames the
file by replacing the last character of the file
extension with a zero. If such a filename
already exists, VTERM uses a 1, then a 2, etc.,
up to 999.)

PROMPT, VTERM prompts you when the new file is
received and gives you the option of aborting,
overwriting, or renaming.

Ctrl-Z Marks End: If you select YES for this setting, VTERM appends a
Ctrl-Z at the end of the file if it lacks one.
Otherwise, VTERM receives the file exactly as it is.

If you select NO, VTERM receives the file exactly
as the host sends it.

If you wish to remove a terminating Ctrl-Z from a
file that already has one (or may have one), enter
<26> in the Remove Characters field (see below). Ctrl-Z
is the normal terminator for PC-DOS text files.

Some programs require terminal Ctrl-Zs, and few
programs are confused by them, so as a general rule
you should select YES for this option.

The table in Figure 17-2 summarizes the effects of setting this
field to YES or NO.
__________________________________________________________
If Ctrl-Z Marks End field is . . .
YES NO
__________________________________________________________
When Stop at first Ctrl-Z Send file exactly
Sending don't send it or as it is.
File following characters.

When Append Ctrl-Z at end Receive file
Receiving of file if it lacks one; exactly as it is.
File otherwise receive file
exactly as it is.
___________________________________________________________
Figure 17-2. Effect of Ctrl-Z Marks End of File

Translate: This field determines whether VTERM translates
certain foreign language characters during file
transfer. Select OFF if you do not want translation.
Select ON if you do. For ASCII file transfer, you
probably want this option ON.

Remove Characters: Use this field to specify characters that you
want VTERM to remove from the file before
writing it on disk. You can enter control
characters in this field between angle brackets
either as decimal values (for example, <13>) or
as mnemonics (for example, ).

CAUTION: VTERM removes spaces from your file
if you accidentally leave a space character in
this field. If there is data in this field,
the small triangular character appears at the
end of the data just as in the filename field.


HOW TO TRANSMIT FILES USING ASCII TEXT TRANSFER

To transmit a file on the PC using ASCII Text transfer, complete
the following steps:

1. Run the host computer program that you are using to capture
the data from the PC. For example, on some DEC operating
systems PIP =KB: begins capturing data. CREATE
might also be used for the same purpose. Any host
program -- including a text editor -- that collects data from a
terminal can be used to receive ASCII Text data from the PC.

2. Press Alt-T for transmit.

3. Complete the fields in the File Transfer Window as described
below. You either toggle the settings with the keypad
Plus (+) key or by type data in data entry fields.

4. Press Alt-T again to start the transfer.

To cancel the transfer, press the Esc key before pressing Alt-T
the second time.

When you press Alt-T the second time, the file transfer Status
Line is displayed. As VTERM sends the data, it displays the
number of characters sent so far in the Bytes field on the Status
Line.

If the data is being echoed back to the terminal you will see it
on the screen, just as if you were typing it very quickly. When
VTERM finishes sending the file, the status line displays
"Transfer Complete."

Once the transfer has started, you can terminate it by pressing
Alt-A, Alt-S (to display Setup Screen One) or the hot key (to
enter DOS).

When VTERM finishes sending the PC file, it ends the transfer and
displays "Transfer Complete" on the Status Line. After the
transfer is finished, press any key to redisplay the terminal
Status Line.

NOTE: Because DOS text files normally end with Ctrl-Z, and PIP
and CREATE stop copying data from the keyboard when they receive
a Ctrl-Z, these DEC utilities usually end automatically at the
completion of an ASCII Text PC-to-host transfer if you have a
Ctrl-Z (<26>) in the Send after transfer field of the ASCII
protocol page in Setup Screen Two.


File Transfer Window Fields for
Transmitting ASCII Text Files

When you press Alt-T the first time, the File Transfer Window,
illustrated in Figure 17-3, appears on the screen. You complete
the fields in the window by toggling with the Plus (+) key or by
typing as appropriate. These fields are described below.

_______________________________________________________
| |
| Filename: \REP\BARB.TXT |
| Protocol: ASCII TEXT |
| |
| |
| Ctrl-Z Marks End: NO |
| Translate: OFF |
| Remove Characters: |
|_______________________________________________________|
Arrow keys select, + changes. Alt-T=Transmit,Esc=Cancel

Figure 17-3. File Transfer Window for Transmitting
ASCII Text Files.

Filename: Type the name of the PC file you wish to send. Any
valid DOS drive specifier and filename may be used,
including subdirectories.

Protocol: Toggle this field until ASCII TEXT appears.

Ctrl-Z Marks End: If you select YES for this setting, VTERM stops
sending at the first Ctrl-Z character it encounters
and doesn't send it or any following characters.
If the file ends without a Ctrl-Z. VTERM does not
send one.

If you select NO, VTERM sends the file exactly
as it is, including Ctrl-Zs if it finds any.

The table in Figure 17-2 earlier in this file
summarizes the effects of setting this field to
YES or NO.

Translate: This field determines whether VTERM translates
certain foreign language characters during file
transfer. Select OFF if you do not want translation.
Select ON if you do. For ASCII file transfer, you
probably want this option ON.

Remove Characters: Use this field to specify characters that you
want VTERM to remove from the file before
sending it to the host. You can enter control
characters in this field between angle brackets
either as decimal values (for example, <13>) or
as mnemonics (for example, ).

CAUTION: VTERM removes spaces from your file
if you accidentally leave a space character in
this field. If there is data in this field,
the small triangular character appears at the
end of the data just as in the filename field.


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