3270 full-screen considerations

You should be aware of the 3270 screen size, cursor select key, error messages, and null characters when using 3270 emulation.

When using 3270 full-screen mode for your Telnet client, you should be aware of the following considerations:

TN3270 screen size

TN3270 Cursor Select key

The existing Cursor Select key is disabled if you choose to emulate the Cursor Select key. Specifying one of the following parameters for the STRTCPTELN command emulates the Cursor Select key:

Table 1. Parameters to emulate the cursor select key
Parameter	Value
Page Up (Roll Down) key	*CSRSLT
Page Down (Roll Up) key	*CSRSLT
Cursor Select key	F-key (specify a function key F1 to *F24)

TN3270 messages

When you are using Telnet 3270 full-screen mode, several types of error messages might display.

Key entry errors appear as flashing 4-digit numbers on the lower left corner of the display. Press the Help key or F1 (Help) to obtain more information about the message. See the System Operation book if you cannot correct the error.
System messages include Telnet messages and are issued from the system.
For information about messages that are sent from the remote system, see the remote system documentation.

TN3270 - Handling null characters

When a 3270 display station sends a data stream, all null characters are removed. Specify one of the following values for the handle nulls (NULLS) parameter on the STRTCPTELN command:

*REMOVE

Removes beginning and embedded null characters

*BLANK

Changes beginning and embedded null characters to blanks. This is the default value. Trailing null characters are always removed for both values. This is the default value. For example, assume the data consists of the following code (0 indicates a null) :

0x0yz000

The data stream sent from a 5250 display station that runs Telnet 3270 full-screen with the default *BLANK contains the following code:

bxbyz

The data stream sent from a 3270 display station or from a 5250 display station running a Telnet 3270 full-screen session when the value *REMOVE is specified would contain the following code:

xyz

The value *REMOVE is valid for the following devices:

Any locally attached display
Displays attached to a remote 5394 controller
Personal computer displays using the workstation function

Parent topic:

3270 Telnet client sessions

Related concepts
Starting a 3270 Telnet client session