Aixton multi-telephone cable

The transmission distance has nothing to do with the number of logarithms. The telephone cable with a wire diameter of 0.4mm has a loss of 1.64dB per kilometer and a loop resistance of 296Ω: if the maximum attenuation of the user line is 7.0dB, the length of the telephone cable with a wire diameter of 0.4mm can reach 4.26 when the attenuation is 7.0dB. Km; if the loop resistance of the subscriber line (voice) is not greater than 1700Ω, the maximum communication distance of a telephone cable with a wire diameter of 0.4mm is 5.74Km, but the attenuation is 9.42dB at this time. If it is less than 900 ohms, the maximum transmission distance is not more than 3Km. Large logarithmic cables are generally divided into 3 types of large pairs and 5 types of large pairs, which are further divided into: 5 pairs, 10 pairs, 20 pairs, 25 pairs, 30 pairs, 50 pairs, and 100 pairs. 200 pairs 300 pairs
Generally speaking, large logarithmic cables are used more in weak current projects, and are mostly used for voice trunks.
1.1 Communication cable concept:
The cable core is composed of a plurality of mutually insulated wires or conductors, and the communication line is provided with a sealing sheath on the outside. Some are also equipped with an outer sheath outside the sheath. There are various laying methods such as overhead, direct burial, pipeline and underwater. According to the structure, it is divided into symmetrical, coaxial and integrated cables; according to functions, it is divided into field and permanent cables (underground and submarine cables). The communication cable has a wider transmission frequency band, a larger communication capacity, and less external interference, but it is not easy to repair. It can transmit telephone calls, telegrams, data and images, etc.
2.1 Overview of Communication Cable Chromatography:
The chromatographic composition of communication cables is always composed of 10 colors, consisting of 5 primary colors and 5 secondary colors; 5 primary colors and 5 secondary colors form 25 colors, no matter how large the number of pairs of communication cables, usually the largest pair Digital communication cables are composed of 25 pairs of colors as a small number of signs.
Usually communication cables are divided into: 10 pairs, 20 pairs, 30 pairs, 50 pairs, 100 pairs, 200 pairs, 300 pairs... 3000 pairs.