Function:                  Audio/video communication    4'' flat B/W CRT(3.5'' /4.0''color digital TFT LCD)       Watch door entrance    Remote lock release    Inter-call with extended phone set    Optional for extended camera or extended monitors.    Optional extended panel for apartments more than 24 in a building.
Data of technology  working voltage: AC11V~220V                                                           working  current: <400mA    wiring:  4 wires    Ambient Humidity: 45%~95%     Resolution: 420(W)*380(H)    Video Output: 15625Hz 1Vp-p 75Ω, PAL or NTSC    installation method: surface  mounting type