Like other GSM phone, GSM-R equipment can transmit data and voice. New GSM-R features for mobile communication are based on GSM, and are specified by EIRENE project. Call features are:
- PtP Call: Point-to-Point Call, the same type of call as a normal GSM call
- VGCS: Voice Group Call System, quite similar to walkie-talkie communication
- VBS: Voice Broadcast System, like a VGCS but only the call initiator can speak (the other are only listeners)
- REC: Railways Emergency Call, it is a special VGCS with high priority dedicated to emergencies.
- Priority control of all the different calls (PtP, VGCS, VBS and REC calls)
There are other additional features:
- Functional Addressing, alias system to call someone registered on the GSM-R network, only by knowing the temporary function user (engine driver of train such-and-such, …)
- Shunting mode, when users work on the tracks.
GSM-R features
ASCI (Advanced Speech Call Items) features
VGCS (Voice Group Call Service)
- VGCS allows a great number of users to participate in the same call. This feature imitates the analogue PMR (Private Mobile Radio) group call with the PTT key (Push-to-Talk).
- Three kinds of users are defined: the Talker, the Listener and the Dispatcher. The talker can become a listener by releasing the PTT key and a listener becomes a talker by pressing the PTT key.
- The main advantage of VGCS compared to multi-party calls (the GSM conference call feature) is the spectrum efficiency. Indeed, when many users are in the same cell they will use only one frequency for all listeners and two frequencies for the talker (as in point-to-point call). In a multi-party call, one timeslot is dedicated to each user.
- VBS is a broadcast group call: this means that compared to VGCS, only the initiator of the call can speak. The others who join the call can only be listeners. This kind of call is mainly used to broadcast
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