Identifying output message destinations

An application program can send messages to another application program or to IMS terminals. To send output messages, the program issues a call and references the I/O PCB or an alternate PCB. The I/O PCB and alternate PCBs represent logical terminals and other application programs with which the application program communicates.

Definition: An alternate PCB is a data communication program communication block (DCPCB) that you define to describe output message destinations other than the terminal that originated the input message.