A registered program is an external program that logs on to the Gateway once (registration); the Gateway then starts a process and sets up a TCP/IP line. The program is then executed, if required.

Using a registered program is particularly advantageous for performance if it is a program that is used very frequently. It avoids having to repeatedly start a new process.

A registered program can be stopped by another program with the CANCEL call (i.e. registration is cancelled), if it is not active at that moment.