Cable: When the phone converts the acoustic signal into an electrical signal and transmits it to the switch via the line, the switch transmits the electrical signal directly to the other telephone through the line. The line transmitted during this call is the cable. The cable is mainly copper core wire. The diameter of the core wire is 0.32mm, 0.4mm and 0.5mm. The larger the diameter, the stronger the communication capability.
There are also 5 pairs, 10 pairs, 20 pairs, 50 pairs, 100 pairs, 200 according to the number of core wires. To wait, the logarithm mentioned here refers to the maximum number of users that the cable accommodates; there is also a package, which I don't quite understand. Cable: It is bulky, heavy, and has poor communication capability and can only be used for short-range communication. Optical cable: When the phone converts the acoustic signal into an electrical signal and transmits it to the switch via the line, the switch transmits the electrical signal to the photoelectric conversion device (converts the electrical signal into an optical signal) and transmits it to another photoelectric conversion device via the line ( Convert the optical signal into an electrical signal), and then to the switching device, to the other phone to answer.
The line between the two photoelectric conversion devices is the optical cable. It is said that it only has the number of cores, and the number of cores is: 4, 6, 8, 12, and so on. Optical cable: its advantages of small size, low weight, low cost, large communication capacity and strong communication capability. Due to a number of factors, it is currently only used for communication between long distances and points and points (ie, two switch rooms). The difference between them: The inside of the cable is a copper core wire; the inside of the cable is glass fiber. Optical cable The communication optical cable is a communication line in which a certain number of optical fibers are formed into a cable core in a certain manner, and a sheath is sheathed, and some are also covered with an outer sheath to realize optical signal transmission. Field trials have been carried out in Shanghai, Beijing, Wuhan and other places.
Soon after, it was used as an inter-office trunk in the city's telephone network. 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 distance, small volume, light weight, no electromagnetic interference.
Since 1976, it has developed a growth trunk line, urban relay, offshore and transoceanic submarine communication. And the backbone of wired transmission lines such as local area networks and private networks, and began to develop into the field of urban subscriber loop distribution networks, providing transmission lines for fiber-to-the-home and wide-generation integrated service digital networks. A cable is usually a cable-like cable made up of several or several sets of wires [at least two in each group]. Each set of wires is insulated from each other and often twisted around a center. The entire outer bread has a height. Insulating covering layer; especially submarine cable first: there is a difference in material. The cable is made of metal (mostly copper, aluminum) as a conductor; the cable is made of glass fiber. Second: There is a difference in the transmission signal. The cable transmits electrical signals. The optical cable transmits an optical signal. Third: There are differences in the scope of application. Cables are now used for energy transmission and low-end data transmission (such as telephone). Optical cables are mostly used for data transmission.