In videosurveillance,coaxial cable,twisted paircable and network cable are used a lot for signaltransmission.The engineerschoosedifferenttransmission modes according to the actual situation.transmission parts and transmission lines used bydifferent cables vary greatly.For example,a coaxialcable is a solid copper core,surrounded by a layer ofinsulation material surrounded by a densely wovennetwork of conductors,and a layer of protectivematerial is covered outside the network. Thefrequency loss,image distortion,image attenuationrange is small,mainly used in small range monitoringsystem,because the transmission distance is veryclose,the use of coaxial cable direct transmission on theimage quality is not much damage,can meetactualrequirements. Generally,special SYV 75 ohmseries coaxial cable is used as video signaltransmission.