Digital 3-Channel FM Wireless Intercom System for Home and Office, 2-Station CALL button to call/page all stations at once, one to one or one to all stations communication No installation required, FM 462 MHz wireless operation To set up designated station - Press and Hold the Channel Button until you hear a beep tone sounds and Button LED lights Direct CHANNEL buttons, with A/B/C channel group switch to avoid unwanted signals AC Adapter included