At the BTR-200 operator’s command, the remotes may communicate with each other, with a wired intercom system or with an auxil- iary system. The BTR-200 Base Station with its one transmit and four receive channels was designed to operate in full duplex (simulta- neous two-way communications) with up to four TR-200 Belt Pack transceivers (one trans- mit and one receive channel) See block dia- gram in figure 1.