23.1353GPPMulticall supplementary serviceRelease 17Stage 2TS
The Multicall supplementary service does not provide multiple traffic channels for speech calls. Refer to Procedure Check_OG_Multicall_MSC and Procedure Check_MT_Multicall_MSC.
If Nbr_UE is greater than Nbr_SN, the mobile station may initiate an Emergency call even if Nbr_SN has been reached. When the network receives an Emergency call Setup message from the mobile station:
– if Nbr_SN has not been reached, the network shall accept it regardless of Nbr_SB or Nbr_User;
– if Nbr_SN has been reached, the network shall reject the emergency call setup attempt. The MS shall release one or more existing calls and it shall re-initiate an Emergency call.
The MS shall ensure that an emergency call Setup request is acceptable to a serving network which does not support multicall, if necessary by releasing one or more existing calls.
6.2 Short message service
6.3 Facsimile service
The Multicall supplementary service provides multiple traffic channels for facsimile service except for alternate speech and facsimile group 3.
6.4 Data circuit asynchronous
The Multicall supplementary service provides multiple traffic channels for data circuit asynchronous.
6.5 Data circuit synchronous
The Multicall supplementary service provides multiple traffic channels for data circuit synchronous.