The GMTRAN system initialization parameter specifies the name of a transaction ID.
or
GMTRAN is initiated when terminals are logged on to CICS by z/OS Communications Server. Do not specify the name of a remote transaction. The transaction must be capable of being automatically initiated (ATI). The default is the transaction CSGM, that displays the text specified in the GMTEXT parameter. Alternatively, you can specify one of the CICS signon transactions, CESL or CESN, which also display the text specified in the GMTEXT parameter. The GMTRAN parameter can be used with the LGNMSG parameter to retrieve z/OS Communications Server logon data.