MS-704, Base station 4-ch. 4-channel base station with built-in speaker for rack mounting that can drive up to 60 beltpacks with associated headsets or 20 speaker stations. Built-in power supply with separate short-circuit protection with automatic reset for each channel. Separate volume controls and program audio inputs for each channel. 3 breakable return channels (IFB) switch for linking channels etc. Intended for rack mounting 19" / 2U.