Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 3: Interworking at the Inter-System Interface (ISI); Sub-part 3: Additional Network Feature Group Call (ANF-ISIGC)
The present document defines the Terrestrial Trunked Radio system (TETRA) supporting Voice plus Data (V+D). It specifies:• general design aspects (e.g. reference points, numbering and addressing, or protocol architecture);• the interworking between TETRA networks;• the interworking of TETRA networks with other networks, via gateways;• the supplementary services applicable to the basic TETRA tele- or bearer services.