Door Controller Operation
Question: What is a door controller?
Answer:

The A-DC800 door controller provides the capability to remotely control the "action" of up to four devices, such as door strikes or lamps. The A-DC800 is shipped with one wall mount A-AB800 action box. The A-DC800 and A-AB800 are installed "in-line" with the observation monitor and camera. Connecting cables from the observation monitor to the A-DC800 (4 ft) and from the A-AB800 to the camera (16 ft) are included. Existing camera cables are used to connect the output of the A-DC800 to the input side of the A-AB800. Connection to the "action" device is made using the relay output screw terminals located inside the A-AB800. The relay output interfaces to the action device using N.C., N.O. and COM connections.