DESC: Talk from any remote to all other remotes/stations. Hands-free answering at all remotes/stations. One button talk/listen: Push to speak, release to hear reply. Private mode prevents unwanted monitoring. Answer door from any remote/station. Control radio and CD player from remote; on/off, select radio memory channels/CD tracks. Control music and intercom volume using built-in control. Use with ISA-77 and IS-79 speakers, one speaker only per remote control. Surface mounts. Includes mounting frame.