Category : Communication (modem) tools and utilities
Archive   : VTRANS.ZIP
Filename : XMODEM.DOC

 
Output of file : XMODEM.DOC contained in archive : VTRANS.ZIP
CHAPTER 18
XMODEM PROTOCOL FILE TRANSFER

XMODEM protocol is a popular method of transferring files from
microcomputer to microcomputer and between microcomputers and
computerized bulletin boards. XMODEM protocol performs automatic
error correction, and because it adds few extra "protocol"
characters to the data, it's relatively fast. Transfers using
XMODEM can involve any kind of data, not just ASCII Text.

On the other hand, XMODEM protocol demands special host-side
software, and there are no standard host utilities to support
XMODEM transfers.

Use XMODEM transfer only when connecting to other computers that
already have XMODEM software.

Before using XMODEM for the first time, you should read "How To
Transfer Files" on page202.


HOW TO RECEIVE FILES
USING XMODEM PROTOCOL

To capture a file on the PC using XMODEM Protocol, complete the
following steps:

1. Start the XMODEM program on the host system.

2. Then type Alt-R (for receive) from the terminal screen.

3. Complete the fields in the File Transfer Window as described
below.

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

You can cancel the transfer by pressing Esc before pressing Alt-R
the second time.

When you press Alt-R the second time, transfer begins immediately
and the file transfer Status Line appears at the bottom of the
screen.

Once the transfer has started, you can terminate it by pressing
Alt-A (for abort), Alt-S (to display Setup Screen One), or the
hot key (to enter DOS while keeping VTERM resident in memory).
As the transfer progresses, the block count and any error
conditions are displayed on the Status Line.

When VTERM finishes receiving the file, the message "Transfer
Complete" appears on the Status Line.

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

Figure 18-1. File Transfer Window for Receiving
Files with XMODEM Protocol


File Transfer Window Fields for
Receiving Files with XMODEM Protocol

When you press Alt-R the first time , the File Transfer Window,
illustrated in Figure 18-1, appears on the terminal screen. You
complete the fields in the window by toggling with the Plus (+)
key or by typing. These 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 XMODEM 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:

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

þ 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.)

þ 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 are sending a file that contains binary data --
an .EXE or .COM file, for instance -- select NO for
for this setting.

The table in Figure 18-2 summarizes the effects of
choosing YES or NO for this option.

__________________________________________________________
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 18-2. 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 binary files, you should specify OFF. For text files
files 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 XMODEM PROTOCOL

To transmit a file on the PC using XMODEM Protocol, you complete
the following steps:

1. Start the XMODEM program on the host system.

2. Then type Alt-T (for transmit) from the terminal screen.

3. Complete the fields in the File Transfer Window as
described below.

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

You can cancel the transfer by pressing Esc before pressing Alt-T
the second time.

When you press Alt-T the second time, transfer begins immediately
and the file transfer Status Line appears at the bottom of the
screen.

Once the transfer has started, you can terminate it by pressing
Alt-A (for abort), Alt-S (to display Setup Screen One), Alt-H (to
display a help screen), or the hot key (to enter DOS while
keeping VTERM resident in memory).

As the transfer progresses, the block count and any error
conditions are displayed on the Status Line.

When VTERM finishes receiving the file, the message "Transfer
Complete" appears on the Status Line.

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

Figure 18-3. File Transfer Window for Transmitting
Files with XMODEM Protocol


File Transfer Window Fields for
Transmitting Files with XMODEM Protocol

When you press Alt-T the first time, the File Transfer Window,
illustrated in Figure 18-3, appears. You complete the fields in
the window by toggling with the Plus (+) key or by typing. The
fields are described below.

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 XMODEM 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 18-2 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 transfer of binary (.EXE or .COM files for example),
you should set option to OFF. For transfer of text files,
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.


  3 Responses to “Category : Communication (modem) tools and utilities
Archive   : VTRANS.ZIP
Filename : XMODEM.DOC

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