This document specifies the MAC layer protocol data units and messages for logical channels on the U_m2 interface.

The information necessary to enable an interoperable MAC layer protocol for a two-slot TDMA logical channels is provided in this document or referenced in other documents as appropriate. This document assumes the reader has a good working knowledge of the two-slot TDMA document suite identified in [8] and of trunked LMR systems as described in [7].