Input Message Types

When IMS reads data that has come from the telecommunication access method, IMS first checks the type of input data. Input can consist of three types of messages:

Input transaction message

This message is routed to an application program for processing, with the first 1 to 8 bytes of the message identifying the transaction code.

Message switch

This message is routed to another terminal, with the first 1 to 8 bytes used as the name of the destination logical terminal (LTERM). The LTERM can be a user ID if the Extended Terminal Option (ETO) is used.

Command message

A command message is processed by IMS itself.