The RECEIVE notification exit (INMRZ04 or INMRZ04R) receives control each time an acknowledgment is received. If the person who issued RECEIVE has several acknowledgments to receive, the exit is invoked multiple times during RECEIVE processing -- once per acknowledgment.

Installations can use this exit to process acknowledgment information. The TRANSMIT startup exit (INMXZ01 or INMXZ01R) can pass a notification string in the transmission. This exit and the RECEIVE acknowledgment notification exit receive the string. When RECEIVE transmits an acknowledgment to the originator of the transmission, the notification string is also included. This exit can use that notification string to tie transmissions to acknowledgments.