When the phone converts the acoustic signal into an electric signal and then transmits it to the switch via the line, the switch then sends the electric signal directly to the other phone to answer. The line transmitted during this call is a cable. Inside the cable are mainly copper core wires. The diameter of the core wire is divided into 0.32mm, 0.4mm and 0.5mm, the larger the diameter, the stronger the communication ability; there are also divided according to the number of core wires: 5 pairs, 10 pairs, 20 pairs, 50 pairs, 100 pairs, 200 Wait, the logarithm mentioned here refers to the number of large users that the cable can accommodate; there are also by package, which I don't know much about. Cable: Its volume, weight and communication ability are poor, and it can only be used for short-distance communication.
When the phone converts the acoustic signal into an electrical signal and transmits it to the switch via the line, the switch then transmits this electrical signal to the photoelectric conversion device (converts the electrical signal into an optical signal) and transmits it to another photoelectric conversion device (the optical The signal is converted into an electrical signal), and then to the switching equipment, to the other phone to answer. The line between the two photoelectric conversion devices is an optical cable. It is said that it only has the number of core wires. The number of core wires is: 4, 6, 8, 12, and so on. Optical cable: its volume, small weight, low cost, large communication capacity, strong communication capabilities, etc. Due to many factors, it is currently only used for long-distance and point-to-point (ie, two exchange rooms) communication transmission.
The difference is that the inside of the cable is copper core wire; the inside of optical cable is glass fiber.
A communication optical cable is a type of communication line in which a certain number of optical fibers form a cable core in a certain way, and is sheathed with an outer sheath, and some are also covered with an outer sheath for optical signal transmission. In 1976, the Bell Institute in the United States built an optical fiber communication experimental system in Atlanta, which used 144 optical fiber cables manufactured by Western Electric Company. In 1980, commercial fiber-optic cables made of multimode fiber began to be used on inter-office trunks and a few long-distance lines in the city. Commercial fiber optic cables made of single-mode fiber were used on long-distance lines in 1983. In 1988, a trans-Atlantic submarine cable was successfully installed between the United States and Britain and France, and a trans-Pacific submarine cable was soon completed. China developed its own communication optical cable in 1978, using multi-mode fiber, and the core structure of the cable was layer twisted. Field tests have been carried out in Shanghai, Beijing, Wuhan and other places. Soon after, it was tried out in the city's telephone network as an inter-office trunk line. After 1984, it was gradually used for long-distance lines and began to use single-mode fiber. Communication optical cable has larger transmission capacity than copper cable, long trunk distance, small size, light weight, and no electromagnetic interference. Since 1976, it has developed into trunk roads, city trunks, offshore and transoceanic subsea communications. , And the backbone of wired transmission lines such as local area networks and private networks, and began to develop into the field of user loop distribution networks in the city, providing transmission lines for fiber-to-the-home and wide-generation integrated service digital networks.
Communication cables are usually rope-like cables twisted by several or several groups of wires [at least two in each group]. Each group of wires is insulated from each other and is often twisted around a center. The whole outer bread has Highly insulating covering; especially submarine cables
: Material is different. The cable is made of metal (mostly copper, aluminum) as the conductor; the optical cable is made of glass fiber as the conductor.
Second: there is a difference in the transmitted signal. The cable transmits electrical signals. Optical cables transmit optical signals.
Third: there are differences in the scope of application. Cables are now mostly used for energy transmission and low-end data information transmission (such as telephones). Optical cables are mostly used for data transmission.