B/W Video Door Phone

Features
1. Converse with visitors and unlock the door in remote distance
2. Visitors are visible during communication and ringing
3. Able to monitor entranceway actively
4. Able to extend for one more wired camera 
5. Adjustable contrast of the monitor 
6. Adjustable volume of the ringing, call signal sound with electronic Chime (Dingdong)  
7. 4 inch B/W Flat CRT screen, 4 wires 
8. Argent Cover
9. Auto shut down time: 45 seconds 
10. Installation method: Placed Flat or Wall-Hung Type
B/W Video Door Phone