ETSI TS 102 361-4 contains technical requirements for Digital Mobile Radio (DMR) trunking systems operating in the existing licensed land mobile service frequency bands, as identified in CEPT/ERC/T/R 25-08 [10].

The present document describes the trunking services and facilities protocol of a scalable Digital Mobile Radio system, which covers three tiers of possible products:

• Tier I: DMR equipment having an integral antenna and working in Direct Mode (unit-to-unit) under a general authorization with no individual rights operation.
• Tier II: DMR systems operating under individual licences working in Direct Mode (unit-to-unit) or using a Base Station (BS) for repeating.
• Tier III: DMR trunking systems under individual licences operating with a controller function that automatically regulates the communications.

NOTE: Tier II and Tier III products encompass both simulcast and non-simulcast systems.

The DMR air interface complies with either ETSI EN 300 113-1 [1], ETSI EN 300 113-2 [2] or ETSI EN 300 390-1 [3], ETSI EN 300 390-2 [4], that has been specifically developed with the intention of being suitable for all identified product tiers.

The DMR protocol is intended to be applicable to the land mobile service frequency bands, physical channel offset, duplex spacing, range assumptions and all other spectrum parameters without need for any change.