4-Channel 3- or 4-Wire Camera Interface Rack Mount (1RU), provides 4 discrete Clear-Com to 3- or 4-wire interface circuits Four channel interface connects Clear-Com to TV cameras, two-way radios, satellite links, and other communications devices through either their headset jacks or 4-wire circuits. IF4W4 has selective partyline capability. Features individual transmit, receive, and null controls, as well as transmit level indicators. Switchable mic or line-level output for compatibility. The built-in test jack and test tone provide quick nulling.