This document explains the basic concepts related to interfacing AT&T Enhanced Push-To- Talk over Cellular (EPTT) with Land Mobile Radio (LMR). On the EPTT side, the capability allows radio channels or talkgroups to appear just like any other EPTT member, with the ability to be included in Push-to-Talk conversations in the same manner as any EPTT user. On the radio side, whenever a radio user begins a transmission on a radio that has been configured in a EPTT talkgroup, that user’s audio is sent to not only the other radios on that channel, but also to any EPTT users in the associated EPTT talkgroup. Likewise, all radio users on that radio channel will hear any audio from associated EPTT talkgroup members.