The authentication service described in this document is applicable to FDMA and TDMA trunking systems using an FDMA trunking control channel. Authentication is a standard option for trunked radio systems. This document describes two forms of authentication: unit authentication and mutual authentication. If the authentication standard is implemented in a SU, then unit authentication is mandatory and mutual authentication is optional. When the mutual authentication option is chosen, it must be implemented as specified herein. If the authentication standard is implemented in the FNE, both unit and mutual authentication are mandatory and must be implemented as specified herein.

This document defines the full standard across the U_m interface.