The present document contains technical requirements for Digital Mobile Radio (DMR) operating in the existing licensed land mobile service frequency bands@ as identified in CEPT/ERC T/R 25-08 [3]. The present document describes the packet data protocol (PDP) 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 (communication without infrastructure) under a general authorization with no individual rights operation. Tier II: DMR systems operating under individual licences working in direct mode 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 1: Tier II and Tier III products encompass both simulcast and non-simulcast systems. NOTE 2: The three tiers of possible products will work only independently and not interoperable. The present document specifies the Packet Data Protocol (PDP) of DMR 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 frequency bands@ physical channel offset@ duplex spacing@ range assumptions and all other spectrum parameters without need for any change.