# OTMA Super Members

You can use Substation ES with OTMA super members as targets for regular messages, triggers and requests/replies.

Consider the following points when configuring and using Substation ES with OTMA super members:

- Multiple Substation ES IMS interfaces can point to the same Tpipes under a super member. They can be in the same Substation ES instance or separate ones.
- IMS will process messages sent from an ESB to any Substation ES that references the TPIPE-DEFAULT plus the super member.
- To support conversational messages, either use the DFSYDRUn and DFSYPRXn user exits to handle `TPIPE-PREFIX=`, or define TPIPE-PREFIX= tpipes from 001 to 255 with the SMEM= parameter.

Note: Note the following points regarding triggers and requests/replies:

- Because of IMS design, only one interface at a time processes triggers and requests/replies; the other interfaces remain idle.
- When an interface terminates, whether planned or unplanned, IMS begins sending traffic to the next interface that becomes active.
- If more than two interfaces are active, IMS will move traffic to the interfaces in the order in which they became active.
- When the first interface becomes active again, it takes its place in line behind the now-active interface.

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