RTS BP-4000-A4M Single-Channel Portable Beltpack Headset Station - 4-Pin XLR, MaleWith the Telex BP4000A4M Single Channel Portable Beltpack Headset Station, you can stay in communication on an RTS, Audiocom, or Clear Com intercom system. This wired beltpack station features auto wiring scheme detection, which automatically recognizes the system you plug it into, and configures itself to be used with it. The beltpack also features intelligent power management, so you can daisy chain up to 40 beltpacks by using a single (optional) PS