An Introduction to IMS: Your Complete Guide to IBMs Information Management System

IMS maintains the name of the terminal or user from which an input message is received. When a message is passed to an application program, this is also made available to that program, via its program communication block (PCB).

This origin is the LTERM name. The LTERM name can be specific to the user, or can be specific to the physical location, depending on how the IMS system is defined.