TCPIP Services, TELNET
*Conan The Librarian (sorry for the slow response - running on an old VAX)
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VMS Help TCPIP Services, TELNET *Conan The Librarian (sorry for the slow response - running on an old VAX) |
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With the TELNET software in DIGITAL TCP/IP Services for OpenVMS,
you can log in to a remote internet system. This is called
establishing a TELNET session. Your terminal appears to be
attached directly to the remote system.
You can establish a TELNET session with a host that uses IBM 3270
model terminals (TN3270).
Note that you can also use RLOGIN to log in to remote internet
hosts. However, RLOGIN does not have the ability to manage a 3270
session.
To use the network terminal services, you need the following:
o A user account on the remote host also running TELNET.
o A user account on the OpenVMS system that runs DIGITAL TCP/IP
Services for OpenVMS.
For more information about specific TELNET commands, enter the
following
$ TELNET
TELNET> HELP
| 1 - Command Summary |
To use TELNET, issue the commands summarized below. For complete
descriptions (including UNIX equivalents) of each command, enter
the following:
$ TELNET
TELNET> HELP
Command Description
Starting (at the DCL Prompt)
TELNET Invokes TELNET
TELNET remote_host Invokes TELNET and establishes a connection
to a remote host
TN3270 Invokes TELNET and TN3270
TN3270 remote_host Invokes TELNET, runs TN3270, and
establishes a connection to a remote host
Getting In and Out of Sessions
CONNECT Establishes a connection between the local
host and a remote host
CREATE_SESSION Establishes a pseudodevice and connects it
to a remote listener port
DELETE_SESSION Deletes a pseudodevice created by the
CREATE_SESSION command
DISCONNECT Terminates your current session
Ctrl/] Takes you from the remote host back to the
TELNET prompt
EXIT Closes open connections and exits from
TELNET
HELP Invokes online help
RESUME Resumes an open connection
SPAWN Suspends your TELNET session and takes you
to the DCL prompt
Customizing the TELNET Environment
DISABLE AUTOFLUSH Disables the automatic flushing of output
when interrupt characters are sent
DISABLE AUTOSYNCH Disables the automatic sending of interrupt
characters in urgent mode
DISABLE BINARY Disables transmission in binary mode
DISABLE CRLF Disables the sending of carriage returns as
Return LF
DISABLE CRMOD Disables the mapping of received carriage
returns
DISABLE DEBUG Disables the display of data flow
information in hexadecimal
DISABLE Disables the interpretation of certain
LOCAL_CHARS control characters by your local TELNET
client and passes them to the remote TELNET
server
DISABLE Disables the display of option negotiations
OPTIONS_VIEW between the client and server
ENABLE AUTOFLUSH Enables the automatic flushing of output
when interrupt characters are sent
ENABLE AUTOSYNCH Enables the automatic sending of interrupt
characters in urgent mode
ENABLE BINARY Enables transmission in binary mode
ENABLE CRLF Enables the sending of carriage returns as
Return LF
ENABLE CRMOD Enables the mapping of received carriage
returns
ENABLE DEBUG Enables the display of data flow
information in hexadecimal
ENABLE LOCAL_CHARS Enables the interpretation of certain
control characters by your local TELNET
client and prohibits them from being passed
to the remote TELNET server
ENABLE OPTIONS_VIEW Enables the display of option negotiations
between the client and server
SHOW PARAMETERS Displays the current parameter settings
SHOW SESSION Displays the current sessions
SHOW STATUS Displays the current status
SET ECHO Sets the echo character to the specified
character
SET ERASE Sets the erase character to the specified
character
SET ESCAPE Sets the escape character to the specified
character
SET FLUSHOUTPUT Sets the flush output character to the
specified character
SET INTERRUPT Sets the interrupt character to the
specified character
SET KILL Sets the kill character to the specified
character
SET MODE Sets the transmission mode to character or
line
SET QUIT Sets the quit character (an alternate
interrupt character) to the specified
character
SET TERMINAL Sets the terminal type to the specified
model
Sending Commands to the Remote Host
SEND AO Sends the Abort Output command
SEND AYT Sends the Are You There command, testing
the path to the remote application and
eliciting connection status information
from the remote host
SEND BRK Sends the Break command
SEND EC Sends the Erase Character command
SEND EL Sends the Erase Line command
SEND GA Sends the Go Ahead command
SEND IP Sends the Interrupt character
SEND NOP Sends the No Operation command to test
whether data can be sent to the remote
host, eliciting an error if the connection
is not open
SEND SYNCH Sends the Synchronize character
| 2 - Command Syntax |
Use the following rules when you enter a TELNET command line.
o Command formats
With the TELNET command and most of the commands at the TELNET
prompt, you can use either DCL-style or UNIX style syntax. For
example, the following two commands produce the same results:
$ TELNET
TELNET> SHOW PARAMETERS
$ TELNET
TELNET> DISPLAY
o Quotation marks
No quotation marks are required for typing:
o The TELNET command line, for example:
$ TELNET CENTRAL
o The TN3270 command line, for example:
$ TN3270 CENTRAL
o Commands at the TELNET prompt, for example:
TELNET> CONNECT CENTRAL
2.1 - Example
The following example connects to UNIX host migain and sets a
terminal type with the /TERMINAL_TYPE qualifier. No quotation
marks are needed to pass a terminal type to migain in lowercase,
as demonstrated with the remote host's printenv command.
$ TELNET MIGAIN /TERMINAL_TYPE=vt300
%TELNET-I-Trying, Trying ...11.90.208.56
%TELNET-I-SESSION, Session 01, host migain, port 23
-TELNET-I-Escape, Escape character is '^]'
Hello from UNIX host migain
login: root
Password:...
.
.
.
migain# printenv
TERM=vt300
HOME=/
SHELL=/bin/csh
USER=root
PATH=/bin:/usr/bin:/usr/ucb:/etc:/usr/etc:.
LOGNAME=root
PWD=/
migain#
| 3 - Starting |
You can start a TELNET or TN3270 session with a remote host (also
called establishing a connection and opening a connection) in one
of the following ways:
o At the DCL prompt, issue either the TELNET or TN3270 command
and specify a remote host.
o At the DCL prompt, issue the TELNET or TN3270 command with no
parameters. At the TELNET or TN3270 prompt that appears, issue
the CONNECT or open command, specifying a remote host.
o Invoke and use TELNET or TN3270 from a command procedure.
3.1 - Example
The following example shows three ways to establish a connection
interactively:
$ TELNET CENTRAL /TERMINAL_TYPE=IBM-3278-2
$ TELNET
TELNET> CONNECT CENTRAL 23 VT200
$ TN3270 CENTRAL /TERMINAL_TYPE=IBM-3278-3
You can invoke TELNET or TN3270 and, without connecting to a
remote host first, enter certain commands that customize the
sessions and display parameters or status.
$ TELNET
TELNET> SHOW STATUS
%TELNET-E-NOSESSION, No active session
Escape character: '^]'
TELNET>SET DEVICE TERMINAL=VT300
TELNET> OPEN GALAXY
%TELNET-I-TRYING, Trying ... 1.20.208.10
%TELNET-I-SESSION, Session 01, host galaxy, port 23
-TELNET-I-ESCAPE, Escape character is ^]
Digital UNIX (galaxy.udb.com) (ttyp5)
login:
| 4 - Exiting |
You can end a TELNET or TN3270 session (close the connection) in
one of the following ways:
o At the remote host's system prompt, log out.
o At the remote host's system prompt, return to the TELNET or
TN3270 prompt and disconnect the session, as follows:
1. At the remote host's system prompt, press the TELNET/TN3270
escape character (Ctrl/] is the default).
2. At the TELNET or TN3270 prompt, issue either DISCONNECT or
close.
4.1 - Example
The following example shows two ways to close connections:
% logout
%TELNET-S-REMCLOSED, Remote connection closed
-TELNET-I-SESSION, Session 01, host galaxy, port 23
TELNET>
TELNET> EXIT
$
% <Ctrl/]> (characters not echoed)
TELNET> DISCONNECT
galaxy.udp.com>
TELNET> DISCONNECT
%TELNET-S-LCLCLOSED, Local connection closed
-TELNET-I-SESSION, Session 01, host galaxy, port 23
TELNET>
| 5 - Logging Sessions |
To keep a log of your TELNET session, use the /LOG_FILE
qualifier. (You cannot use this qualifier with a TN3270 session.)
The following example establishes a TELNET connection to node
central, sets the terminal type to VT200, and logs all session
output to the file CENT.LOG in your current directory.
$ TELNET/LOG_FILE=CENT.LOG/TERMINAL_TYPE=VT200 CENTRAL
| 6 - Command Procedures |
You can create a command procedure containing the DCL DEFINE and
TELNET (or TN3270) commands.
You can create initialization command files to customize your
TELNET/TN3270 sessions with SET, ENABLE, and DISABLE commands.
These command files:
o Are optional. They eliminate the need to issue individual
TELNET commands.
o Have the following requirements:
- Location: Your login directory
- Name: TELNETINIT.INI
- Format: one command per line
o Run automatically when you invoke TELNET or TN3270.
o You can specify the logical name, TELNETINIT, to point to an
initialization file.
6.1 - Example
The following example shows a TELNET initialization command
procedure.
! This file, TELNETINIT.INI, sets my TELNET parameters
! the way I like them.
!
DISABLE AUTOFLUSH
ENABLE BINARY
ENABLE DEBUG
SET DEVICE /TERMINAL=VT300
SET ESCAPE "^p"
| 7 - Toggling |
During a session with a remote host, you can toggle back and
forth between the local TELNET or TN3270 process and the
connected host. For example, at the TELNET prompt, you might
want to display status, modify a TELNET parameter, or spawn a DCL
subprocess.
o To return to the local TELNET or TN3270 prompt (TELNET command
mode), enter the TELNET escape sequence (the default is
Ctrl/]) at the remote host's prompt (TELNET input mode).
o To resume your session with the remote host, enter one of the
following at the TELNET (or TN3270) prompt.
TELNET> <Return>
or
TELNET> RESUME
or
TELNET> RESUME n
where n is the number of the session to which you want to
return.
o To change the default escape sequence, enter the following at
the TELNET (or TN3270) prompt:
TELNET> SET ESCAPE "^escape_character"
7.1 - Examples
1. The following example toggles between remote UNIX host biway
and the local OpenVMS system.
biway> <Ctrl/]> (characters not echoed)
TELNET> SHOW STATUS
Session 1 Active Host biway Port 23
Operating Mode: Character-at-a-time
Escape character: '^]'
Options:
Echo - Remote
Terminal Type - Local
Terminal Type - VT300
Suppress Go Ahead - Local
Suppress Go Ahead - Remote
Terminal Dataoveruns: 0
Suspended Network I/Os: 0
.
.
. )
TELNET> <Return>
biway>
2. In the next example, user BENTLEY, working at OpenVMS node
EAGLE, uses TELNET to do the following:
1. Establish a connection to UNIX host fern.
2. Return to the local TELNET prompt.
3. Display status.
4. Establish a connection to host gannet.
5. Return to the TELNET prompt.
6. Display status.
7. Connect to sands. But, sands closes the connection because
BENTLEY incorrectly enters the password three times.
8. Try to resume the session with gannet. However, RESUME
without specifying a session number fails:
- With multiple sessions, RESUME's default is the
"active" session, the one with the most recently opened
connection.
- The most recent host to which BENTLEY connected is
sands. However, due to BENTLEY's incorrectly typing
of the password during login, sands closed the TELNET
connection. Thus, TELNET displays "No current session."
- Because no connection is "active" (or "current"),
BENTLEY must specify a session number on the RESUME
command line.
$ TELNET FERN
.
.
.
fern> <Ctrl/]> (characters not echoed)
TELNET> SHOW STATUS
Session 1 Active Host FERN
.
.
.
TELNET> CONNECT GANNET
.
.
.
gannet> <Ctrl/]> (characters not echoed)
TELNET> SHOW STATUS
Session 2 Active Host GANNET
Operating Mode: Character-at-a-time
Escape character: '^]'
.
.
.
Session 1 Waiting Host FERN
TELNET> CONNECT SANDS
%TELNET-I-Trying, Trying...11.18.222.95
%TELNET-I-SESSION, Session 03, host sands, port 23
-TELNET-I-Escape, Escape character is '^]'.
.
.
.
Sun Microsystems, Inc. UNIX System sands - Authorized Access Only
Username: BENTLEY
Password:
User authorization failure
Username: BENTLEY
Password:
User authorization failure
Username: BENTLEY
Password:
User authorization failure
Remote connection closed
TELNET> RESUME
No current session
TELNET> SHOW STATUS
Session 1 Waiting Host FERN
Session 2 Waiting Host GANNET
.
.
.
TELNET> RESUME 2
gannet> <Ctrl/]> (characters not echoed)
TELNET> SHOW STATUS
Session 2 Active Host GANNET
Operating Mode: Character-at-a-time
Escape character: '^]'
.
.
.
Session 1 Waiting Host FERN
TELNET>
| 8 - Suspending |
While using TELNET, you can use the SPAWN command to suspend
your current session and create a subprocess at the local DCL
prompt. At the DCL prompt, you can then enter any number of DCL
commands. To return to your suspended TELNET session (exiting the
DCL subprocess), enter the LOGOUT command.
8.1 - Example
In the following example, the user suspends the TELNET session
to list the files in the working directory on the local host and
deletes one of the files in that directory.
TELNET> SPAWN
$ DIR
.
.
.
$ DEL TR3.TXT:*
| 9 - Multiple Sessions |
TELNET supports:
o Multiple simultaneous connections
o Up to 10 simultaneous sessions
o Only one session at a time if it uses TN3270
The TELNET SHOW STATUS command helps you keep track of multiple
sessions.
o Toggling Sessions
To toggle from one open TELNET connection to another:
1. Enter the TELNET escape sequence.
2. If necessary, issue SHOW STATUS to check the number of your
session with the other host.
3. Issue the TELNET RESUME n command, where n is the number of
the session to which you want to return.
o Session Information
To display a list of your active sessions, use the SHOW
SESSION command:
TELNET> SHOW SESSION <Return>
Session 01, host finder, port 23
Session 02, host keeper, port 23 (default active session)
If there are no active connections, the SHOW SESSION command
displays the following message:
%TELNET-E-NOSESSION, No active session
| 10 - Customizing |
To customize the TELNET/TN3270 processing environment, issue
ENABLE, DISABLE, and SET commands. You can modify how TELNET and
TN3270:
o Send and receive transmissions
o Display processing on your terminal
o Interpret certain control characters
You can redefine the following control characters, such as
when your terminal or the remote host does not recognize the
corresponding default control character.
o Echo
o Erase
o Escape
o Flush output
o Interrupt
o Kill
o Quit
Use the SET command to redefine these characters. For example,
the following command defines the interrupt character to be the
letter a or A.
TELNET> SET INTERRUPT "^a"
TN3270 allows you to redefine your keyboard. You can redefine
most IBM 3270 model functions and all emulated functions and
characters. You can create a key definition file with DEFINE/KEY
statements to redefine the keyboard. Or, you can redefine a key
interactively, using the DEF KEY function (Ctrl/K on VT100- and
VT200-series terminals).
You can determine the mode TELNET uses to transmit data. The
appropriate TELNET mode for a session depends on:
o The remote host to which you are connecting
o The applications you use
The following table shows the modes that control TELNET
communications.
Mode Function
Local Characters The local host interprets control characters,
Mode translating them in to TELNET protocol
sequences (ENABLE LOCAL_CHARS). Use this mode
when the local and remote hosts implement
different control characters. By default,
characters are interpreted by the remote host
(DISABLE LOCAL_CHARS).
Binary Mode The local host sends transmissions in binary
mode (ENABLE BINARY). Use this mode when the
remote host expects each line of data to end
with a carriage return/line feed combination.
By default, the local host sends transmissions
with the end-of-line character (EOL) mapped
to the carriage return/line feed combination
(DISABLE BINARY).
Debug Mode TELNET displays data flow in both hexadecimal
and readable text (ENABLE DEBUG). By default,
TELNET displays data in readable text only
(DISABLE DEBUG).
Character TELNET transmits data one character at a time
Transmission (SET MODE CHAR) rather than line-by-line. Use
Mode this mode when you run a text editor (on the
remote host) that does character processing.
Character transmission mode is the default.
Line TELNET transmits data one line at a time (SET
Transmission MODE LINE). Most clients send a character at a
Mode time. The remote host server must support line
transmission mode.
This allows you to do signal trapping as well
as local character editing and tab expansion.
| 11 - TN3270 |
You can run a TELNET session with a host that uses IBM 3270 model
terminals by using the TN3270 command. The TN3270 command:
o Provides IBM 3270 Information Display System (IDS) terminal
emulation.
o Assigns IBM 3270 functions to your DIGITAL keyboard.
o Assigns IDS functions to specific keys.
During a TN3270 session, you can:
- Redefine keys interactively (DEF KEY Function).
- Redefine keys permanently (Key Definition File).
- Record your sessions (Recording Sessions).
- Troubleshoot problems (TN3270 Troubleshooting).
NOTE
When you run TN3270, you can only have one session. You
cannot have other sessions running simultaneously, as you
can when running normal TELNET sessions.
TELNET can emulate the following IBM 3270 model terminals:
Model Screen Size (Rows x Columns)
IBM 3278 Model 2 24 x 80
IBM 3278 Model 3 32 x 80
IBM 3278 Model 4 43 x 80
IBM 3278 Model 5 27 x 132
11.1 - Terminal Setup
When you use TELNET and specify IBM 3270 model terminal emulation
(TN3270), the image displayed on your screen depends on the type
of DIGITAL terminal you use (or that your PC is emulating) and
the features you set on it.
o VT200 Series Terminals
Follow these steps:
1. At the Set-up Directory menu, select the keyboard type
that corresponds to the keyboard layout you are using (for
example, North American).
2. At the Display Set-up menu, select the following:
o Interpret controls
o Light text, dark screen
o Cursor (visible)
3. At the General Set-up menu, select the following:
o VT200 or VT100 mode (if VT100 mode, set VT100 ID)
o 7-bit or 8-bit controls
o Multinational/national
o Normal cursor keys
o No new line
4. At the Communications Set-up menu, select the following:
o XOFF at 64 or XOFF at 128
o 8-bit communication line
o 8-bit (any) parity
o No local echo
5. At the Keyboard Set-up menu, select warning bell ON.
At the DCL prompt, issue:
$ SET TERMINAL /INQUIRE
The software determines the terminal's characteristics and
sets the appropriate parameters.
If you select National Character mode, issue:
$ SET TERMINAL /NOEIGHTBIT
o VT100 Series
Follow these steps:
1. Set your terminal to ANSI mode (see the user's guide for
your terminal).
2. Enter the following command at the DCL prompt:
$ SET TERMINAL/INQUIRE
This command causes the terminal to be questioned about
its characteristics. The appropriate parameters for the
terminal are set up according to its response.
TN3270 requires DIGITAL terminals or DECterm windows that
support at least 24 lines and 80 columns.
11.2 - Starting and Exiting
Start a TN3270 session by using the TN3270 command. You can also
use the TELNET/TERMINAL_TYPE=IBM-3278-n command. The default
terminal type is IBM-3278-2.
You can invoke TN3270 and, without connecting to a remote host
first, enter certain commands that customize the sessions and
display parameters or status. You can also use a command file to
invoke TN3270 and the customization.
The TN3270 command includes several qualifiers that allow you to
specify customized or special files for the following:
o Character set translation tables file (/CHARACTER_SET=file)
that translates between EBCDIC and the DIGITAL Multinational
Character Set. The default file, if set up by your system
manager, is SYS$LIBRARY:TN3270DEF.TBL. If this file does not
exist, and you do not specify a file, TN3270 uses its own
translation table.
o Keyboard definition file (/KEY_DEFINITIONS=file) that you
create as an alternative to the default keyboard layout.
o National Replacement Character Set (NRCS) file (/NATIONAL_
CHARACTERS=n) for which your DIGITAL terminal is configured.
The default for 8-bit terminals is MULTINATIONAL. The default
for 7-bit terminals is US_ASCII.
You can end a TN3270 session (close the connection) in one of the
following ways:
o At the remote host's system prompt, log out.
o At the remote host's system prompt, return to the TN3270
prompt and disconnect the session, as follows:
1. At the remote host's system prompt, press the TN3270 escape
character (Ctrl/] is the default).
2. At the TN3270 prompt, issue either DISCONNECT or close.
Clearing Error Messages
TN3270 displays error messages in a bordered display at the
bottom of your screen. This display overwrites the status display
and remains visible until you clear it. To clear, invoke one of
the following functions:
o REFR
o HELP
o SET FIL
o DEF KEY
Recording Sessions
During a TN3270 session, you can record your screen's contents.
The PRINT function directs your screen's contents to either a
file or a spooled printer.
To record your screen's contents, follow these steps:
1. Invoke the PRINT keyboard function, as explained in the topic
Keyboard_Functions.
The screen display is recorded in a file in a compressed
state. Null lines (lines with only nulls and attribute
characters) do not appear.
2. Invoke the ENTER function or any function that transmits the
screen contents to the remote host's application, as explained
in the topic Keyboard_Functions.
This creates the default output file, TN3270PRINT.LIS. TELNET
does the following:
o Each time you start a TELNET session that runs TN3270, TELNET
opens a new TN3270PRINT.LIS file.
o Each time you use PRINT during a session, TELNET appends new
output from the screen to the end of TN3270PRINT.LIS.
o Each time you use PRINT, if you direct the output to a
printer, TELNET creates a separate entry in the print queue.
o If the printer is spooled, TELNET immediately prints the
output.
You can specify a different file name. To change the name, use
one of the following two methods:
o When you start a TN3270 session, use the /PRINTER qualifier.
Issue:
$ TN3270 [ host ] /PRINTER=file
o During a TN3270 session, follow these steps:
1. Use the SET FIL keyboard function, as explained in the
topic Keyboard_Functions.
2. At the prompt for a new file name, enter a name.
If you specify the same name that is already in use,
subsequent PRINT operations direct output to a new version
of the same file.
3. Use the NEW LINE keyboard function, as explained in the
topic Keyboard_Functions.
Locked Keyboards
If your keyboard locks, the terminal bell rings, and the status
line displays:
Inhib
To unlock the keyboard, press the following key to invoke the
RESET function (KP0 refers to the 0 key in the application keypad
on the right hand side of the keyboard):
<KP0>
Do not use the following functions when the cursor is in a
protected field (a field that does not accept user input):
o DELETE
o DUP
o ER EOF
o FM
o Any graphic character
| 12 - TN3270 Keyboard Functions |
The options listed below under "Additional Information Available"
describe the keyboard functions. Preceding each function
description are the key sequences for VT100 and VT200 terminals
and the function name to use in a DEFINE/KEY command. In many
of the key sequences, TN3270 allows use of the extended function
(EXT) feature. Used in conjunction with another key, EXT allows
access to an extended function for that key. The extended
function feature is described below in more detail.
12.1 - ATTACH
VT100: EXT + E VT200: EXT + Find
DEFINE_KEY Function: ATTACH
Changes control from one subprocess to another subprocess or to
the parent process. When you invoke the ATTACH function, TN3270
uses the name of the last process to which you attached as the
default process name.
If you want to attach to a different process, press Ctrl/U to
erase the default process name. You can then enter the process
name of your choice at the prompt. The process name can be a
quoted string. Use the quotation marks to preserve spaces, tabs,
or lowercase letters in strings.
12.2 - ATTN
VT100: EXT + A VT200: F19
DEFINE_KEY Function: ATTENTION
Provides a way to "get the attention of" the remote application
program that you are running by sending a SIGNAL RU command
to the remote host. See the user's guide of the particular
application program to learn what response the program gives
when you use this key.
12.3 - Back Tab
VT100: BACKSPACE VT200: F12
DEFINE_KEY Function: BACK_TAB
Moves the cursor, depending on the type of screen. On a formatted
screen, the cursor moves one of these ways, depending on the
location when you press this key:
o If the cursor is in a field, but not at the first position of
the field, it moves to the beginning of the unprotected field
that it is in.
o If the cursor is in the first position of a field, it moves
to the beginning of the preceding unprotected field. If the
cursor is in the first position of the first unprotected
field, the cursor moves to the first position of the last
unprotected field on the screen.
On an unformatted screen, the cursor returns to the first
position on the screen.
12.4 - Cent Sign
VT100: EXT + C VT200: EXT + C
DEFINE_KEY Function: (None)
Enters a cent sign. If your terminal does not have this
character, your screen displays a hyphen ( - ).
12.5 - CLEAR
VT100: EXT + Enter VT200: EXT + F20
DEFINE_KEY Function: CLEAR
Clears the screen and moves the cursor to the first position
on the screen. When you invoke the CLEAR function, the software
notifies the application program that this function has been
used.
12.6 - DEF_KEY
VT100: Ctrl/K VT200: Ctrl/K
DEFINE_KEY Function: DEFINE_KEY
Lets you interactively define or redefine a key. You get a prompt
for the name of the key to define and for a function you want to
assign to that key.
12.7 - DELETE
VT100: Delete VT200: <X]
DEFINE_KEY Function: DELETE
Deletes the character at the cursor. The cursor remains where it
is, and the other characters to the right of the cursor in the
same field move one position to the left. The end of the field
fills with blanks. Note that this is not the action normally
associated with the Delete key on DIGITAL terminals.
12.8 - DSP_ATT
VT100: Ctrl/V VT200: EXT + F17
DEFINE_KEY Function: DISPLAY_ATTRIBUTES
Enables and disables the visible attribute mode. This mode of
operation forces display of the attribute characters (that
is, the characters at the start of a field that indicate the
display and data type of that field). In IBM 3270 model terminal
emulation (TN3270), you can use the DSP ATT function to debug
application programs.
12.9 - DUP
VT100: EXT + * VT200: EXT + F12
DEFINE_KEY Function: DUP
Lets you enter a value in the same field in several forms without
needing to repeat the entry for each form.
After entering the data in the field on the first form, use the
DUP function when at the same field on succeeding forms. The
application program makes the necessary translation, filling in
these fields with the same value. For details about the use of
this key, refer to the user's guide of the particular application
program.
Displays an asterisk (*).
12.10 - DV_CNCL
VT100: EXT + U VT200: EXT + Remove
DEFINE_KEY Function: DVCNCL
Cancels the RECORD function. Use the DV CNCL function if you
begin using the RECORD function and then decide you want to stop.
If you want to delete a sequence that has already been recorded
on a PF key, use the RECORD function, press the PF key, and then
use the DV CNCL function.
12.11 - ENTER
VT100: Line Feed + Enter VT200: Do + Enter
DEFINE_KEY Function: ENTER
Sends your input to the remote application program. While this
communication is active, the keyboard locks and Inhib appears
on the status line. Usually the application program releases the
keyboard when it has finished processing your input.
12.12 - ER_EOF
VT100: EXT + KP, VT200: F18
DEFINE_KEY Function: ERASE_EOF
Erases the contents of the current field, from the location of
the cursor to the end of the field. The cursor remains in the
same location.
12.13 - ER_INP
VT100: EXT + KP- VT200: EXT + F18
DEFINE_KEY Function: ERASE_INPUT
On a formatted screen, clears all the data in the unprotected
fields on your screen and moves the cursor to the first position
in the first unprotected field on the screen.
On an unformatted screen, clears all the data and moves the
cursor to the first position on the screen.
You can also use the ER INP function to remove all previously
recorded key sequences by using the RECORD function and then the
ER INP function.
12.14 - EXIT
VT100: Ctrl/Z or F10 VT200: Ctrl/Z or F10
DEFINE_KEY Function: EXIT
Terminates the remote TELNET/TN3270 session. Aborts any exchange
of data in progress between the local and remote hosts. Note that
terminating a session with the IBM host in this way may result in
improper termination of the session. For the appropriate logoff
command string, see the user's guide for the IBM application with
which you are communicating.
12.15 - EXT
VT100: KP. VT200: KP.
DEFINE_KEY Function: EXTEND
Used in conjunction with another key, allows access to an
extended function for that key. First invoke the EXT function
and then press the second key. If you invoke EXT accidentally,
invoking the RESET function cancels the EXT function.
If the status display is enabled when you invoke the EXT
function, the word Extend appears on the status line.
12.16 - FM
VT100: EXT + ; VT200: EXT + F13
DEFINE_KEY Function: FM
Specifies the end of a field on an unformatted screen or the end
of part of an unprotected field on a formatted screen. Refer to
the user's guide of the remote application program for specific
use of this key.
Displays a semicolon ( ; ).
12.17 - HELP
VT100: EXT + H VT200: Help
DEFINE_KEY Function: HELP
Displays online help and an illustration of the TN3270 keyboard.
12.18 - HOME
VT100: EXT + B VT200: F13
DEFINE_KEY Function: HOME
Repositions the cursor to the first position in the first
unprotected field on the screen (that is, to the beginning of
the input area on the screen).
12.19 - Left/Right Arrows
VT100: Right arrow or VT200: Right arrow or Left arrow
Left arrow
DEFINE_KEY Function: RIGHT, RIGHT_NOWRAP, LEFT, or LEFT_NOWRAP
Moves the cursor horizontally across your screen without changing
data you have already entered. If the cursor is at the:
o End of a line when you use the Right arrow function, the
cursor moves to the start of the next line.
o Beginning of a line when you use the Left arrow function, the
cursor moves to the end of the previous line.
If the screen display you receive is wider than 80 columns,
you can use the Right arrow and Left arrow functions to move
through the display.
If you want the cursor to wrap to the opposite edge of the
display, use one of the following function sequences:
EXT + Right arrow
EXT + Left arrow
12.20 - INSERT
VT100: EXT + PF4 VT200: F14
DEFINE_KEY Function: INSERT_MODE
Enables insert mode. Use insert mode to edit what you entered. If
the status display is enabled, Insert appears.
In insert mode, when you enter a character in to an unprotected
field, it is displayed to the left of the cursor, moving the
following one position to the right:
o The cursor
o The character at the cursor location
o All the characters to the right of the cursor in the field
You can insert characters in to an:
o Unformatted screen
o Unprotected field on a formatted screen until it is full
If you attempt to insert characters after the field is full,
the keyboard locks, the terminal bell rings, and the word Inhib
appears on the status line. If the keyboard locks when you try
to insert characters in to a field that looks empty, the field
might have trailing spaces. To erase these spaces, use the ER EOF
function.
To return your screen to the normal mode of entry, use one of the
following keyboard functions:
o RESET
o CLEAR
o ENTER
o Any PA key
o Any PF key
12.21 - Logical Not
VT100: EXT + N VT200: EXT + N
DEFINE_KEY Function: (None)
Represents the remote host's symbol for a logical NOT; displayed
as a circumflex ( ^ ) on DIGITAL terminals.
12.22 - Logical Or
VT100: EXT + O VT200: EXT + O
DEFINE_KEY Function: (None)
Represents the remote host's symbol for a logical OR; displayed
as a solid vertical line from the terminal's graphics set. Press
Ext + O if the vertical bar is not available on your keyboard.
12.23 - New Line
VT100: Return VT200: Return
DEFINE_KEY Function: NEWLINE
Moves the cursor to the first unprotected position on the next
line of your screen. If no unprotected fields are on the screen
when you invoke the new line function, the cursor moves to the
first location on the screen. If the screen has no fields,
this key has the same function as the Return key on DIGITAL
terminals.
12.24 - NUM_OVR
VT100: EXT + J VT200: Remove
DEFINE_KEY Function: NUMOVR
Lets you enter nonnumeric characters in to numeric fields. Once
you enable this function, use NUM OVR again to disable it. If you
do not disable the numeric lock override, it remains enabled even
after you exit from TN3270. The letter O appears on the status
line to indicate that the numeric lock override is in effect.
12.25 - PA Keys
VT100: PF4 , KP- , KP, VT200: PF4 , KP- , KP,
DEFINE_KEY Function: PA1-PA3
These program access keys are defined by the program you are
using. These keys request attention from the remote application
program without sending any data. You should refer to the user's
guide of your application program to learn how the PA keys are
defined.
12.26 - PF Keys
VT100: see below VT200: see below
DEFINE_KEY Function: PF1-PF24
These program function keys are defined by the remote application
program you are using. They request attention from the
application program and send the data entered to the host. The
PF keys are coded by the application program to perform functions
relating to the application. A particular PF key may be coded
differently from one application to another. The user's guide of
the remote application program usually defines the specific PF
key assignments for that application program.
To
Implement
This Press This Key or
Function Key Combination
PF1 PF1
PF2 PF2
PF3 PF3
PF4 KP7
PF5 KP8
PF6 KP9
PF7 KP4
PF8 KP5
PF9 KP6
PF10 KP1
PF11 KP2
PF12 KP3
PF13 EXT + PF1
PF14 EXT + PF2
PF15 EXT + PF3
PF16 EXT + KP7
PF17 EXT + KP8
PF18 EXT + KP9
PF19 EXT + KP4
PF20 EXT + KP5
PF21 EXT + KP6
PF22 EXT + KP1
PF23 EXT + KP2
PF24 EXT + KP3
12.27 - PLAY
VT100: EXT + M VT200: Insert Here
DEFINE_KEY Function: PLAY
Recalls keystroke sequences stored on PF keys using the RECORD
function. Invoke the PLAY function and then press the PF key
on which the desired key sequence is stored. The PLAY function
executes all commands included in the keystroke sequence.
If the HELP utility is invoked in your key sequence, the PLAY
function continues until you exit from the HELP utility. Also,
if you use functions that require you to respond to prompts (such
as ATTACH, DEF KEY, SET FIL, or SPAWN), the information you enter
at the prompt is not recorded. When you recall the sequence, the
system prompts you for this information again.
P appears on the status line if the status display is enabled.
12.28 - PRINT
VT100: EXT + P VT200: F11
DEFINE_KEY Function: PRINT
Records the contents of your screen in a file or at a printer.
(This is a local print feature.) If the status display is enabled
when you use the PRINT function, the word Print appears on the
status line. Your screen refreshes when the printing process
completes.
The first use of PRINT in a given run of TN3270 creates a new
version of the output file. Successive uses of PRINT in the same
program cause the screen contents to append to the existing file.
If the output is directed to a printer, each use of PRINT creates
a separate entry in the printer queue. If the printer is a
spooled printer, the output is released for printing immediately.
Use the command qualifier /PRINTER=file to specify where to
direct the output file. The SET FIL function allows you to
change the name of the output file each time you invoke the PRINT
function.
12.29 - RECORD
VT100: EXT + L VT200: EXT + Insert Here
DEFINE_KEY Function: RECORD
Saves a keystroke sequence on a specific PF key. Invoke the
RECORD function with the appropriate key sequence (as described
above), press the PF key as prompted, enter the keystroke
sequence, and then invoke the RECORD function again. You can
save a maximum number of 127 keystrokes on each PF key. If the
status display is enabled when you use the RECORD function, the
letter R appears on the status line.
To recall the keystroke sequence, use the PLAY function. Use
the DV CNCL function to cancel the RECORD function. To erase all
previously recorded key sequences, use the ER INP function.
12.30 - REFR
VT100: Ctrl/W VT200: Ctrl/W or F20
DEFINE_KEY Function: REFRESH
Removes TN3270 error messages, operating system messages, or
other messages that appear on your screen. This key function
deletes extraneous characters from your screen and redisplays the
fields and data that were on the screen before the interruption.
This function does not transmit or receive data from the remote
host. It is a local OpenVMS function.
12.31 - RESET
VT100: KP0 VT200: KP0
DEFINE_KEY Function: RESET
Returns the keyboard to normal input mode from insert mode. Also,
the RESET function returns the keyboard to your control after
it locks when you try to enter data in to a protected or a full
field, or when you try to enter the wrong type of data in to a
field.
Invoking RESET turns off the Inhib indicator. The cursor remains
where it is and the screen remains unchanged.
12.32 - SELECT
VT100: EXT + K VT200: Select
DEFINE_KEY Function: SELECT
Lets you choose items from a menu, table, or list and then notify
the program of your selection. Use the arrow keys to position
the cursor on the field designator character, then use the SELECT
function. For more information on using SELECT, refer to the
user's guide of the remote application.
12.33 - SET_FIL
VT100: EXT + F or Ctrl/F VT200: EXT + F11
DEFINE_KEY Function: SET_PRINTFILE
Lets you change the name of the file or device that receives
output each time you invoke the PRINT function. After you invoke
SET FIL, you are prompted for the name of a new output device,
emulating the remote host's IDENT function.
Note that if you specify the same name that is already in use,
subsequent PRINT operations direct output to a new version of the
same file.
12.34 - SHO_MSG
VT100: EXT + G VT200: EXT + F14
DEFINE_KEY Function: SHOW_MESSAGE
Displays the broadcast messages that have been posted on a
separate screen. If the status line is enabled, Msg appears on
the status line. If you do not read the messages before they fill
up the screen, the messages begin to scroll up out of view and
you will no longer be able to read them. These broadcast messages
are not saved after you read them or exit TN3270.
12.35 - SPAWN
VT100: EXT + D VT200: Find
DEFINE_KEY Function: SPAWN
Creates a subprocess under the current process. Use the
LOGOUT command to terminate the subprocess. Because a tree of
subprocesses can be established using the SPAWN function, you
must be careful when terminating any process in the tree. When a
process is terminated, all subprocesses below that point in the
tree are terminated automatically.
When you create a subprocess, you can specify an optional
command string. The command string is executed within the created
subprocess and the subprocess terminates upon completion of the
command.
12.36 - STATUS
VT100: EXT + S VT200: F17
DEFINE_KEY Function: STATUS
Lets you enable and disable the display of status information.
When you enable STATUS, the last line on your screen is painted
over with a reverse video strip. This line may conceal remote
host system or application information. If this occurs, Hidden
appears in the status line.
Disable the status display by using the STATUS function again.
12.37 - SYS_REQ
VT100: EXT + R VT200: EXT + F19
DEFINE_KEY Function: SYS_REQUEST
Lets you shift between the application program (the LU-LU
session) and the control program (the SSCP-LU session). If the
status display is enabled, Appl or SSCP appears on the status
line to indicate the type of session. Appl appears when you are
in an LU-LU session and SSCP appears when you are in the SSCP-LU
session.
The screen is refreshed when you use the SYS REQ function.
12.38 - Tab
VT100: Tab VT200: Tab
DEFINE_KEY Function: TAB
Moves the cursor to the first character location of the next
unprotected field on your screen. If the screen has no fields,
the Right arrow | function moves the cursor to the first location
on the screen.
If the cursor is within the last unprotected field on the screen,
the cursor moves to the first position of the first unprotected
field on the screen.
12.39 - Up/Down Arrows
VT100: Up arrow or Down VT200: Up arrow or Down arrow
arrow
DEFINE_KEY Function: UP, UP_NOWRAP, DOWN, or DOWN_NOWRAP
Moves the cursor vertically on your screen without altering the
data you have already entered.
If the cursor is at the:
o Top of the screen when you press the up arrow, the cursor
appears in the same column at the bottom of the screen
o Bottom of the screen when you press the down arrow, the cursor
appears in the same column at the top of the screen
If the screen display you receive is larger than 24 rows
deep, you can use the Up arrow and the Down arrow keys to
move through the display. These keys scroll the screen display
up or down.
If you want the cursor to wrap to the opposite edge of
the display, use the key sequence EXT + Up arrow or
EXT + Down arrow.
| 13 - Redefining TN3270 Keyboard |
You can reassign functions and keys.
To redefine a keyboard key, use either of the following methods:
o Create a key definition file, a text file with individual
key definitions in the form of DEFINE/KEY statements and
DELETE/KEY statements.
o Use the DEF KEY function (see DEF KEY Function).
The following example establishes a TELNET/TN3270 connection
to host JUNCO. By default, the terminal functions as if it were
an IBM-3278-2 model terminal. It uses your customized keyboard
definition file NEW_KEYS.DAT.
$ TN3270 JUNCO /KEY_DEFINITION=NEW_KEYS.DAT
You can also reassign the following functions:
o All emulated functions
o Most IBM 3270 model functions
o All emulated alphanumeric and graphic characters
13.1 - Definable Keys
The keys you can define are:
Location Key Name
Function keys PF1-PF4
(VT100 and VT200)
Application keypad KP0-KP9
(VT100 and VT200) ENTER
MINUS
COMMA
PERIOD
Top-row function keys F6-F20
(VT200) HELP (F15)
DO (F16)
Editing keypad (E1-E6) FIND (E1)
(VT200) INSERT_HERE (E2)
REMOVE (E3)
SELECT (E4)
PREV_SCREEN (E5)
NEXT_SCREEN (E6)
Cursor keys UP
(VT100 and VT200) DOWN
LEFT
RIGHT
Control keys Ctrl/A-Ctrl/Z, including:
(VT100 and VT200)
Ctrl/H (BS)
Ctrl/I (HT)
Ctrl/J (LF)
Ctrl/M (CR)
Excluding:
Ctrl/Y-Interrupt
Ctrl/C-Cancel/interrupt
Ctrl/O-Output off/on
Ctrl/S-Suspend output
Ctrl/Q-Resume output
13.2 - Nondefinable Keys
You cannot redefine the following DIGITAL-reserved keys:
o Ctrl/Y - Interrupt
o Ctrl/C - Cancel/interrupt
o Ctrl/O - Output off/on
o Ctrl/S - Suspend output
o Ctrl/Q - Resume output
o F1-F5
13.3 - Key Definition File
Use the DEFINE/KEY and DELETE/KEY statements to create your own
key definition file as described in the following sections.
The DEFINE/KEY statement assigns a new function to a particular
key. Its format is:
DEFINE/KEY [/STATE=EXTEND] key_name function
/STATE Optional. Default: non-extend mode.
Redefines the key in extend mode.
key_name Standard key name on the DIGITAL terminal.
function TN3270 function you want mapped to this key.
You can define most of the named keys both in normal (non-extend)
mode and in extend mode.
You can define the control keys (and the synonyms for them) only
in normal mode. Do not specify the qualifier /STATE=EXTEND.
The following example assigns the EXIT function to the key
sequence EXT + Z :
DEFINE/KEY/STATE=EXTEND "Z" EXIT
The DELETE/KEY statement removes the function assigned to a
particular key. Its format is:
DELETE/KEY [/STATE=EXTEND] key_name
/STATE Optional. Default: nonextend mode. Deletes the key
in extend mode.
key_name Standard key name on the DIGITAL terminal.
13.4 - DEF KEY Function
Use the DEF KEY function to define or redefine a key
interactively. Your new definition exists until you log out from
the remote host or disconnect from it.
When you invoke the DEF KEY function, TN3270 displays a prompt
in the status line at the bottom of your screen. What you enter
during the DEF KEY dialog is subject to translation from the
National Character Set to the DIGITAL Multinational Character
Set.
You cannot redefine a key that exists on your National Character
Set terminal if it lacks a DIGITAL Multinational Character Set
equivalent.
| 14 - TN3270 Troubleshooting |
During a TELNET session in which you have invoked TN3270, you
might experience the following problems:
Problem
o The keyboard keys do not work properly.
o Messages, such as the status line messages, do not appear in
reverse video.
o You receive a message indicating that your terminal is an
unsupported model.
You cannot use TN3270 on a VT131 model terminal that is
running in block mode.
Solution for a VT100-Series Terminal
Use Set-Up mode to verify that your terminal is in ANSI mode.
Issue the following command:
$ SET TERMINAL /INQUIRE
Solution for a VT200-Series Terminal or a Terminal Connected to
Either a DIGITAL Personal Computer or a Workstation
1. Use Set-Up mode to verify that your terminal is:
o In ANSI mode
o Set to VT100 or VT200 emulation mode
2. Check the Communications Menu:
The terminal communications line must be set for 8-bit
characters. To check, issue the following command:
$ SET TERMINAL /INQUIRE
Solution for a Terminal with a National Language Keyboard
Ensure that your terminal is set up to correspond to your
keyboard.
Problem
You receive a message indicating that the screen size (or the
alternate screen size) specified by the remote host is too big.
Solution
Use Set-Up mode to change to a valid screen size.
Problem
You try to use the RECORD or PLAY function, but you get an error
message indicating that you have a bad key sequence file.
Solution
The file that stores the recorded key sequence is incompatible
with the current version of the software or is corrupted.
Ask your system manager to do either of the following:
o Correct TCPIP$RECSEQ.DAT in your SYS$LOGIN directory.
o Delete TCPIP$RECSEQ.DAT.
If the system manager must delete this file, rerecord all the
key sequences you had stored on the PF keys.
| 15 - Debugging with TN3270 |
Visible attribute mode provides a way to debug application
programs. After you use the DSP ATT (display attributes) function
to enable visible attribute mode, all attribute characters are
visible. Attribute characters are characters that appear at the
start of a field to indicate the following information:
o How the field appears on the screen:
- At normal intensity
- At high intensity
- Invisibly
o What type of data the application expects in the field:
- Numeric
- Alphabetic
- Alphanumeric
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