22.0873GPPService descriptionStage 1TSUser-to-User Signalling (UUS)
For the purposes of this TS, the following definitions apply:
User-to-User Information (UUI): The information transferred by using the UUS supplementary service.
UUS service: The UUS services (Service 1, 2 and 3) are components of the UUS supplementary service. If the UUS supplementary service is provided to a subscriber, she can handle the UUS services independently within a call.
Served subscriber: The subscriber who has a provision of the UUS supplementary service and who activates the UUS supplementary service. For service 1 and 2 the served subscriber is always the calling subscriber, for service 3 either the calling or the called subscriber can be the served subscriber.
Remote party: For service 1 and 2 the remote party is the called party of a call to which the UUS supplementary service is activated by the served subscriber. For service 3 the remote party can be either the called or the calling party of an established call to whom the use of the UUS supplementary service is requested by the served subscriber.
For the purposes of this TS the following abbreviations apply.
UUS User-to-User Signalling
UUI User-to-User Information
Further GSM related abbreviations are listed in TS 21.905 .