Coaxial cables and twisted pairs are commonly used transmission cables in monitoring systems. They have their own advantages in transmission. Customers can choose according to the wiring environment and needs based on understanding the characteristics and differences of the following two types of cables. Then, Let’s learn about the application differences between coaxial lines and twisted pairs in monitoring systems!

coaxial line

It is one of the common transmission media in local area networks. It has strong anti-interference ability, stable transmission, reasonable price and wide application range. According to the characteristics of the coaxial line itself, the higher the frequency of the signal transmitted within the coaxial line, the greater the attenuation, and the attenuation is limited. Coaxial lines can only be used for short-distance image signal transmission, and when the transmission distance is about 200 meters, the signal quality is significantly reduced, the tone resolution is reduced, and the distortion becomes larger.

Actual monitoring requires extending the transmission distance through a coaxial amplifier. The coaxial amplifier has the function of amplifying video signals and reducing the distortion rate of remote output video signals. However, amplifiers are not infinitely cascadable. In a point-to-point system, only 2 to 3 coaxial amplifiers can be cascaded. If more than one are cascaded, the quality of the video signal cannot be guaranteed, so even through the amplifier, the transmission range is only 400 -500m.

twisted pair

Twisted pair wire is indispensable in integrated wiring projects. By twisting mutually insulated copper core wires, it has the effect of preventing some electromagnetic wave interference from the outside. In monitoring systems, by densely twisting their conductors, interference can also be reduced and signal transmission and quality stabilized. The twisted pairs used in monitoring projects are generally Category 5e or Category 6 lines. For video signal transmission, direct transmission through twisted pairs often inevitably experiences attenuation. In order to achieve long-distance transmission of video signals on twisted pairs, Distance transmission, amplification and compensation are essential.

By adding a twisted pair signal amplification unit, images can be transmitted to places 1~2km away. In addition, twisted pair and twisted pair amplifiers have low cost and convenient wiring. Not only does it not increase the overall cost, but the cost of long-distance transmission is lower than that of coaxial cable. This is also an important reason why many current analog monitoring systems often transmit through twisted pairs.

The advantage of coaxial line is that it can support high-bandwidth communications in relatively long lines without repeaters, but its shortcomings are also obvious. One situation is that if the size is larger, the diameter of the thin cable becomes 3/8 inch thicker, taking up a lot of space in the cable duct. The second is that it cannot stand entanglement, pressure and severe bending. These will damage the cable structure and prevent signal transmission; the cost is very high, and all these shortcomings can be overcome by twisted pair, so in the current LAN environment, the Ethernet physical layer specification based on twisted pair has basically been replaced.

In cable TV transmission, coaxial lines are widely used in medium and small transmission systems due to their low cost and convenient construction. Especially in the "one kilometer" transmission of the HFC network, it cannot be replaced by other cables. Many passive devices, active devices, and users require cabling and impedance matching between all devices connected via coaxial lines. If they are not consistent, signals will reflect between components and cables, and the impact of noise and ghosting on the transmitted image will increase.

The above introduction is the application difference between coaxial cable and twisted pair cable in the monitoring system. If you need to know more, you can contact us at any time!