The MVS WTO and WTOR Macros

Both JES3 and MVS™ can use the MVS write-to-operator (WTO) or write-to-operator-with-reply (WTOR) macros to issue messages.

You can specify information on the WTO and WTOR macro that is similar to that on the MESSAGE macro. In addition, you can also specify whether subsystems can or cannot modify the message's original routing information. See z/OS MVS Programming: Authorized Assembler Services Reference SET-WTO for information about using the WTO or WTOR macro.