How to connect the line 4 of the building intercom system (I measured the voltage)

There are identification letters from the branch circuit board to the socket of each extension. Generally, it is power supply+12V, GND (negative pole), A/B or R/T (data transmission line), AU (audio positive pole), AG (audio negative pole), VI (video positive pole) and VG (video negative pole).

If it is not visible, there is no video group. Find and check the color of the line, then align the interface and connect the corresponding line on the new extension. Generally red 12V, yellow GND, blue s and black p. ..

Extended data:

Working principle:

Visitors can easily call residents and talk to them through the host in front of the downstairs unit. Residents control the switch of the unit door indoors, and the host in the community can receive the alarm signal of residents at any time and send it to the host on duty to inform the community security personnel. The system not only strengthens the safety precautions of high-rise residential buildings, but also greatly facilitates residents and reduces many unnecessary troubles of going upstairs and downstairs.

Working mode:

The door of the building is always locked at ordinary times to prevent people who are not in the building from entering the building without permission, and residents in the building can freely enter and leave the building with their keys. When guests visit, they need to press the room number of the visited household on the intercom keyboard outside the building door and call the intercom extension of the visited household.

The owner of the visited household makes a two-way call or visual call with the visitor through the intercom equipment, and confirms the identity of the visitor through the voice or image of the visitor. After confirming that visitors can enter, the owner of the household uses the unlock button on the intercom extension to control the electric door lock on the entrance door of the building to open, and the visiting guests can enter the building. After the visiting guests enter the building, the door of the building locks automatically.

Building intercom system-Baidu Encyclopedia