Standard and visual talkback phone.

Features:
1. Standard and visual talkback phone. Once the indoor phone receives the calling from the door station, the indoor phone will ring and display the visitor image automatically.
2. After talking, the host press the unlock button to open the door.
3. The door phone could call the management unit and communicate with it.
4. Image adjustment: The host could adjust the contrast and luminance potentiometer to get the best image effect.

5. Volume adjustment: The host could press the switch to get the sound effect.
6. Hang up the phone and the screen is off automatically. It could reduce the waste of electricity.
7. Could install the secondary confirmation door phone additionally.
8. Color display with 4 inch or 5. 5 inch LCD screen.