audio intercom system 1. very cheap price 2, easy installation 3, very clear voice and long ... , villas, hotels, offices, public buildings etc. two-way call and intercom.convenient for double rooms .Directions for use • Plug into 220V ... level >70dB ( AT 0.5m ) 5. quiescent current <5uA 6. intercom working current <100mAWire connection Picture show Industry audio intercom system with doorbell