3270 master terminal support

A 3270 terminal can be the IMS master terminal. When the IMS master terminal is a 3270 terminal, IMS sends all system messages to the primary device. IMS also sends selected system-generated messages critical to IMS operation to the secondary device.

A 3270 master terminal consists of two 3270 devices: a 3270 display (3275, 3276, 3277, or 3278) and a 3270 printer (3284, 3286, 3287, 3288, or 3289). IMS defines the 3270 display as the primary master terminal and the 3270 printer as the secondary master terminal. IMS does not support the 3284 Model 3 as a master terminal.

IMS responds only to the primary device in the following situations:

• When you enter erroneous information, such as a nonexistent transaction code or an invalid parameter, from the master terminal
• When another operator switches a message specifically to the primary device
• When an application program inserts a message to the primary device
• When IMS issues a command-completed message or output from a /DISPLAY command

If the secondary device is non-operational, IMS saves enqueued messages for transmission when it becomes operational.

The /ASSIGN command allows independent assignment of the 3270 display and 3270 printer.