# Prerequisites

CICS Transaction Server for z/OS is necessary for interfacing with Substation ES.

The external communications interface (EXCI) primarily communicates with programs and other resources in the CICS region. The following requirements must be met:

- Substation ES requires that the `CICSHLQ.SDFHEXCI` data set or a copy of the data set should be APF-authorized.
  Note: This data set must be included in the `STEPLIB` library of the Substation ES startup procedure.
- The `USERHLQ.LOAD.CICS#X` library that is installed as part of Substation ES must be concatenated in the DFHRPL DD name of your CICS startup procedures.
- You must ensure that the CICS region is LE-enabled and that the CICS region startup JCL or procedure also includes the LE runtime libraries.
- The CICS Resource definitions required by Substation ES are included with the product and must be added to the CICS CSD during installation.
- To write a message to a guaranteed data queue, the IBM RRS server must be active and you must set the RRMS SIP parameter in CICS to YES. This setting aims to guarantee delivery messages to EMS or use an HVT facility.

Copyright © TIBCO Software Inc. All rights reserved.