The audio door telephone system is mainly composed of host, extension, UPS power supply, electric control lock and door closer. According to the type, it can be divided into direct press type, digital type, digital household communication, direct press type visual intercom, digital visual intercom, digital household communication visual intercom, etc.

The internal structure of the electronic control lock of the audio door telephone is mainly composed of the electromagnetic mechanism. As long as the user presses the electric lock key on the extension, the electromagnetic coil can be energized, so that the electromagnetic mechanism drives the linkage to move, and the door can be controlled to open. The door closer is a special automatic door closing linkage. It has an adjuster, which can adjust the acceleration and action force, and is convenient and flexible to use.