xtalk Command

AIXLink/X.25 1.1 for AIX: Guide and Reference

xtalk Command

Purpose

Enables you to initiate or receive calls over SVCs and communicate with another user by typing messages or sending and receiving files.

Syntax

xtalk [ -l Name ] [ -n ] [ -s ] [ -q ]

Flags

-lName	Specifies the name in the xroute table that should be listened for.
-n	Runs the xtalk process in the background to listen for calls and notify you when they arrive. When a call arrives, you can start the xtalk process again in the foreground and then choose whether to accept or reject the call.
-s	Bypasses (does not produce) the initial copyright screen.
-q	Removes copyright screen after showing it. User not required to press Enter.

Description

The xtalk command enables you to initiate or receive calls over SVCs and communicate with another user by typing messages or sending and receiving files. xtalk can be used on any port that has the COMIO emulation enabled.

Note: The xtalk command works over X.25 ports that have COMIO emulation configured.

The xtalk command has some features that are analogous to using a telephone. To have a conversation or transfer files, one party must first make a call and the other party must receive and accept the call. The xtalk command enables you to do the following:

Listen for calls.
Make a call.
Receive a call.
Have a conversation.
Transfer files.
End a call.

You can store the details of the systems you want to communicate with under a symbolic name in an address list. The xtalk command allows you to view, change, add, or delete entries in this list.

The xtalk -n command runs the xtalk process in the background to listen for calls and notify you when they arrive. When a call arrives, you can start the xtalk process again in the foreground and then choose whether to accept or reject the call.

The xtalk -l EntryName command listens for calls for the routing list entry specified by the EntryName parameter.

Two other flags enable you to manipulate the display of the title screen for the xtalk menu program. The xtalk -q command displays the title screen for two seconds; the xtalk -s command suppresses the display of the title screen.

To converse, each user types messages. Your messages and the other user's messages appear on your display. You can record in a log file the messages you exchange during a conversation.

Starting the xtalk Command

Both hosts must have the xtalk command running in order to communicate. The calling host runs the xtalk command to initiate a call. The called host runs the xtalk command, either in the foreground or the background, to listen for incoming calls from other users. The same command can be used for both the calling and called host. Enter the following:

xtalk -s -l IBMXTALK

where IBMXTALK is the identification of a record in the routing table giving the characteristics of the incoming calls that must be routed to the xtalk application. The IBMXTALK entry is a default entry in the routing table supplied with the X.25 program.

If you want to run the xtalk command in the background to listen for incoming calls, enter the following:

xtalk -n -l IBMXTALK

The xtalk command displays a screen with the following options:

TALK	Allows you to make calls to another user.
ADD	Permits the addition of new entries in the system address list or in your local address list.
BROWSE	Enables you to see all of the data associated with a name in either address list.
CHANGE	Allows you to change the information for an entry in the address lists.
DELETE	Allows you to delete an entry in the address lists.
QUIT	Ends an xtalk session.

The xtalk screen also displays the first few names in the system address list and the local address list (if one exists).

Making a Call

The TALK option on the xtalk main screen allows you to exchange messages with another user. You can specify the user you want to call in one of the following ways:

Use the Up and Down arrow keys to scroll to the desired name in the local or system address list. To switch between the two lists, use the

F2

TALK

Use the Left and Right arrow keys to select the TALK option, and then press

Enter

Note: If you type a name and an X.25 port, the xtalk command uses the port you type instead of the port specified in the address list entry for that name.

Use the Left and Right arrow keys to select the TALK option, and then press

Enter

Accepting a Call

If you have the xtalk command running in the background, the command sends you a message when there is an incoming call. You must have the xtalk command running in the foreground to accept a call. When the xtalk command is running in the foreground, the command displays a screen listing the caller, the caller's address, and the COMIO emulator port. The screen gives you the option to accept or reject the call. Select ACCEPT to receive the incoming call.

Exchanging Messages

When a user accepts an incoming call, the xtalk command displays a commands screen on both the calling and the called host. The options on the commands screen are as follows:

TRANSFER FILE
BEGIN LOGGING
END LOGGING
CHANGE LOG FILENAME
QUIT CALL

With the commands screen options, you can choose to transfer files or log the messages between hosts. To exchange messages, press the F2 key to switch to the message screen. The messages typed by both users appear on the message screen of each host.

Transferring Files

To transfer a file with the xtalk command, one user sends the file, and the other user can choose to accept or reject it. If a file of the same name already exists on the recipient's system, the recipient can choose to append or overwrite the existing file, or save the transferred file under a new name.

To transfer files, you must first make or receive a call by using the xtalk command. When a call is accepted, the xtalk command displays the commands screen or the message screen on both hosts.

If you are sending a file to another user and the message screen is displayed on your machine, press the F2 key to display the commands screen. Use the Up or Down arrow key to select the FILE TRANSFER option, and then press the

Enter

If you are receiving a file and the commands screen is displayed on your machine, press the F2 key to display the message screen. To receive the file, use the Left or Right arrow key to select the ACCEPT option. The xtalk command displays a screen containing the name of the file. You can change the name of the file being transferred by typing a new name in this screen.

Once a file transfer has been accepted by the called user, either user can cancel the file transfer by pressing the Esc (Escape) key.

Creating Address List Entries

Each user that you can talk to over an X.25 network has a network user address (similar to a telephone number). So that users can make calls without knowing another user's network address, the xtalk command maintains a system address list that is available to all users. The system address list is stored in the /etc/xtalk.names file. You must have root user permissions to change the entries in the system address list.

Each user can also choose to keep a local address list containing modifications and additions to the system address list. An entry for a user in your local address list overrides the entry for the same user in the system address list. The xtalk command stores entries for a local address list in the $HOME/xtalk.names file.

To make an entry in an address list, select the ADD option from the xtalk Main menu screen. The Add screen contains the following fields:

Name	Enter a name of up to 15 characters. The name must start with a letter and consist of letters and digits.
Port	Enter a valid COMIO emulation port name of the form x25snn, where nn is the port number. The port name must be the name of one of the COMIO emulators configured onto one of the X.25 ports.
Address	Enter a valid network user address (NUA) of up to 15 decimal digits.
Extended Address	Enter a valid extension of up to 32 digits. The extension address is valid only on networks implementing the 1984 version of X.25. This field is optional.
Facilities	Enter up to 32 hexadecimal characters that represent 16 bytes transmitted in the facilities field in the call request packet. This field is optional.

Making a Call

This procedure uses the xtalk command to make a call on an SVC from a DTE named Host1 to a DTE named Host2.

Note: In the following procedure, IBMXTALK identifies a record in the routing table giving the characteristics of the incoming calls that must be routed to the xtalk application.

On Host2, load xtalk to listen to the IBMXTALK entry in the routing table. Enter the following:
```
xtalk -s -l IBMXTALK
```
On Host1:
1. Load the xtalk command. Enter the following:
```
xtalk -s -l IBMXTALK
```
2. Use the ADD option to create an entry in the address list for Host2.
3. Select the TALK option to call Host2.
On Host2, accept the incoming call, and then press the F2 key.
On Host1, press the F2 key and enter a message. It is transmitted on the network then displayed on Host 2.
Notes:
1. If you have only one system, open two windows (or two sessions). In the first window, start one copy of the xtalk command that corresponds to the called machine and that will listen for incoming calls whose characteristics are defined in the routing table entry IBMXTALK:
```
xtalk -s -l IBMXTALK
```
  In the other window, start the xtalk command without a routing parameter:
```
xtalk -s
```
  Ignore the warning message You cannot receive incoming calls by pressing the Esc key. You can now proceed from this window the same way as explained for the system Host1.
2. The xtalk command cannot be used to test permanent virtual circuits (PVCs). Use the sample programs instead. These programs are located in the /usr/"Licensed Program" Product/bosext2/x25app/samples directory and in /usr/samples/sx25/comio for AIX Version 4 users.

Problems

The xtalk command indicates a device driver problem by displaying a message that begins with CIO Status , as in the following message:

CIO Status 68 - X25_NAME_USED
The name is already being listened to.

These messages correspond to device driver return codes. If you have already tested the connection to the network, the most likely error messages are those related to the routing table:

`CIO Status 68 - X25_NAME_USED`	The name is already being listened to. Another copy of the xtalk command is probably running in the background and listening to IBMXTALK. Remember to always use the QUIT option to end the xtalk session and not the F3 key.
`CIO Status 77 - X25_TABLE`	Could not update routing list. A copy of the xroute command is probably still running or a lock file xroute.lck has been left in the /etc/locks directory.
`CIO Status 73 - X25_NO_NAME`	There is no such name in the routing list. The -l parameter does not match an entry in the routing list.

Two other problems are also related to the routing:

The call has been cleared with cause 00 and diagnostic 00.
Means that the call has reached the remote system but has not been transmitted to an application. Either the application (the xtalk command) is not loaded, or it has not been started with the -l IBMXTALK flag, or the IBMXTALK entry in the routing table doesn't exist or doesn't contain a CUD matching the one in the incoming call packet (FD).
The call has been cleared with cause 00 and diagnostic F4.
This is a diagnostic generated by the xtalk command on the called DTE meaning that the xtalk command received the call but was not ready to accept it (not on the main menu).

If you get a message like the following, you have an X.25 protocol problem.

The call has been cleared with cause 13 and diagnostic 43.

The cause and diagnostic codes are hexadecimal values indicating the cause of the problem. These codes may be generated by the local system, the PSDN or the remote DTE.

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