After the connection has been set up, the OSI TP partner or UPIC clients can start conversations. To this end, the TAC is set by the client, e.g. using the Set_TP_Name function on the CPI-C interface or a corresponding entry in the side information file. This TAC is transferred to openUTM, possibly in conjunction with authorization data. When the sign-on check has been performed successfully, the following apply:
In the case of OSI TP partner and UPIC clients with no sign-on service, the service associated with the TAC is started immediately.
In the case of UPIC clients with a sign-on service, the service associated with the TAC is not started until the sign-on service has been concluded.
The user is signed off again at the end of the conversation if he or she signed on for this conversation under a real user ID. This is not valid for UPIC clients in applications generated with SIGNON OMIT-UPIC-SIGNOFF=YES, see "Sign-on process for UPIC clients and TS applications".