The main traditional medium used to transfer video signals have coaxial cable, twisted-pair cable and optical fiber, the corresponding transmission equipment are coaxial video amplifier, video transmission equipment twisted-pair and optical transceiver. 1. Coaxial cable transmission Coaxial cable is used earlier, also be used the longest time,which has advantages of cheaper price , laiding more convenient. But the transmission distance is limited, in the use of monitor and control system, in order to ensure a better camera video quality (hidden camera spy), the transmission distance limited in 4 or 5 hundred meters. 2. Twisted-pair cable transmission Twisted-pair cable transmission apply more extensive in IP network monitoring, as long as the IP network exist where there is a twisted-pair cable transmission to use, the access method is simple, laiding cost is low. But the same transmission distance is limited, better twisted-pair cable networks can only achieve 200 metres. 3. The fiber optic transmission--Optical fiber transmission have many advantages such as bandwidth high, with great capacity, not by the electromagnetic interference, by external environment impact small and so on , a single fiber can transmit all the signals of supervisory system needs , the transmission distance can achieve hundreds of kilometers. In recent years due to the rapid development of optical fiber communication technology, optical fiber monitoring system costs are also greatly reduced, so fiber and light transceiver's application in monitoring system is becoming more and more popular. In fact, different transmission way also means that different video camera monitoring access method (spy pen camera), coaxial cable transmission still is the main way of simulated monitoring transmission. While the twisted-pair cable,optical fiber transmission of digital monitoring , and that means front-end equipment support Ethernet access or fiber-optic access.from: wireless spy camera
