Dual channel 4 wire audio interface - The PS260(T) is designed to interface an ASL intercom system to external audio equipment or to a 4-wire intercom system. This allows fixed 4-wire systems to be temporarily extended with ASL intercom stations, or a 4-wire TV camera intercom can be connected directly onto an ASL network. Other applications for the PS 260 might be the injection of external audio signals into ASL intercom lines or monitoring of the intercom signals by recorders or paging systems.