... and multi-appartment; 3, PBX system for multi-appartment; 4, Wireless system;7435 CX/NCX descriptionFuction:1, Audio/video communication ... , inspection and Remote unlock;3, Support extended phone set;4, Inter-call with extended phone set;5, Support two ... distributor;Working Current: B/W<600 mA, Color< 400mAWiring: 4 Wires;Communication Duration: 45~90 secAmbient Humidity: 45%~95%Ambient Temperature ...