3GPP43.068Release 16Stage 2TSVoice Group Call Service (VGCS)
VGCS can not be used with standard Phase 1 or Phase 2 mobile stations. A dedicated mobile station with VGCS capability is required.
A mobile station with VGCS capability shall also provide the complete functionality in order to allow the use of Phase 2 services.
Standard Phase 1 and Phase 2 mobile stations in a network shall not be impacted by the presence of VGCS services in that network due to VGCS signalling, also if the mobile station is operated with a SIM/USIM of a VGCS service subscriber.