Clear-Com TW adaptor module: A 2-channel/3-pin XLR adapter module. Combines two intercom channels onto a single 3-pin cable for use with the RS-603 beltpacks.
Model 45A Two-Wire to Four-Wire Interface: Designed to interface a 2-wire full-duplex party-line( PL) intercom circuit with a 4-wire audio circuit associated with a matrix intercom system.