Ideal for replacing and repairing existing analogue systems. Compatible with most door intercom systems. Can be used for installation in 4+n systems (5 audio wire) and in systems 1+n (2 wires). Features a traditional call for buzzing or electronic call on the speaker of the microphone. Door opener button and additional button for additional services. Volume control for input and output., Weight: 0.110231131 pounds, Manufacturer: URMET