Audio Intercom Specifications Bidirectional communication and intercommunication with 2 additional intercoms. Power supply 12VDC @ 1A. Connection: 4 wires (positive, negative, audio and data). SKU Description 0010974 Intercom 110V 60Hz 0010979 Intercom 220V 50Hz Related Products: Audio Intercom KitsAudio intercoms with outdoor station Outdoor StationOutdoor station for Yale intercoms Intercom + Electric Lock KitsKits with Audio Intercoms and Electrical Rim Locks