Functionality Intercom function, Monitoring an entrance Calling with neighboring houses Door lock release Intercom with guide station OSD function Volume & Brightness / Contrast control isitor photo save(option) Specifications Display : 4.3 inch Color TFT-LCD Power : AC90V~240V, 50Hz/60Hz SIZE : 272(W)*158(H)*30(D) Installation : Surface well mount type Conversation time : Waiting time(about 30 seonds), Operating(about 60 seconds) Wiring : Front door 4 Cable(polar), Guard-room 2 cable(nonpolar) Switch 2 cable(polar)