This exit routine, from JES3 input command processing (module IATCNIA in the CONCMD DSP), allows the user to modify a JES3 command and validate the console's authority to enter the command. If the operator enters a JES3 command at a console that has been defined as not having a high enough authority level for that command, the command will be rejected. You can use this exit to allow a particular command to be issued from a console whose definition would reject the command.

You can also use this exit to change input command text or to completely process a command within the exit.

If you do not use exit 18, the console authority levels for RJP consoles are as specified on the LEVEL= parameter of the CONSOLE initialization statement, and for MCS consoles by direct conversion using MCS default values (for example, the master console has a JES3 console authority level 15, and a console with MCS system authority has JES3 console authority 5). z/OS JES3 Initialization and Tuning Reference contains more information about defining console authority levels. z/OS JES3 Commands explains the default authority levels for MCS consoles.