# CICS Interface Messages

This section describes the messages that relate to the Substation ES CICS Interface.

When CICS or EXCI API calls and commands are issued from Substation ES modules, programs, or servers, the following items are returned:

- Return code (RC)
- Reason code (RSN)
- Response codes (DFHRESP)

If a nonzero or invalid code or response is received, the condition is recorded in the Substation ES log and trace files.

When CICS provides Substation ES with the necessary information, the recorded message contains an ID3 message line, which contains CICS-specific information. For details on interpreting this message, refer to Message Line Format.

Copyright © TIBCO Software Inc. All rights reserved.