What is the number of lines that a surveillance camera needs to use?
3, the control line (it is the PTZ, the spherical camera control line, with a two-core dvvr line)
2, video cable (transmission video signal, syv75-3, syv75-5, syv-75-7 these three are the most commonly used)
1, the power cord (12v power supply and 220V power supply, dvvr2 * x, is to the camera power supply)
