Control line, a security industry term, refers to the line of the control circuit in the security industry, which is relative to the main circuit. [1-2]
Control line In the security industry, it refers to the line of the control circuit, which is relative to the main circuit. In general production equipment, there are always main circuits and control circuits. [1-2]
In the analog security monitoring system, if a camera equipped with a pan tilt zoom lens is installed and controlled by a pan tilt lens controller, the selection of control line shall be determined according to the distance between the camera and the cloud tilt lens controller. When the distance is less than 100m, the control line of PTZ can use rvv6 × 0.5 sheathed line,; When the distance is more than 100 meters, the control line of PTZ shall adopt rvv6 × 0.75 sheath line, and the control line of lens shall adopt rvv4 × 0.5 sheath line. If the analog monitoring system controls the pan tilt and lens through the matrix control host, a decoder is generally required. For the laying of control lines, refer to the technical requirements of the matrix control host.
In the digital monitoring system, if a camera equipped with a pan tilt zoom lens is installed, the pan tilt and lens need to be controlled by a decoder. The decoder is generally installed next to the camera, and the decoder communicates with the digital video recorder using the rs485 bus. Wiring shall adopt rvvp2 × 1 Shielded twisted pair From the digital video recorder to the nearest decoder 1, and then from decoder 1 to decoder 2... The current 16 channel digital video recorder can be connected to 16 decoders at most, and the total length of the rs485 communication line can be up to 1200 meters. The wiring diagram is as follows: see the relevant posts in Basic Knowledge. The decoder has two power supply types: ac 220v and ac 24v. If the ac 24v decoder is selected, it is generally powered by the ac 24v transformer. In particular, it should be noted that some decoders output dc 12v power supply with interference, which will have a certain impact on the image when used for camera power supply, so it is necessary to uniformly power the camera (12v). [1-2] 
