Hi There, I posted before looking for a inexpensive intercom for a job and saw a contractor with a good idea. I went to a 10 stop job today that had some Radio Shack 4 Channel wireless catalog # 43-3102 intercoms taped on each landing wall with blue tape and the elevator operator maintained them. They used 4 AA batteries and had no limit to units to connect and were programable with rocker dip sw for application and had 200 ft range and sounded good. They were $59.00 each. No wires and no power supply. Jim

-- Jim (elevator555@hotmail.com), October 12, 2004