Part of the following content comes from relevant columns of Baidu Encyclopedia and Zhihu @ Beijing Kelan, and the rest is my own understanding and summary.
We know that the maximum transmission distance of general network cables is generally about 100 meters. In the network construction of campus networks or medium and large enterprises, if only network cables are used for information transmission, network hardware such as relay equipment needs to be configured, which has caused a certain degree of trouble to the installation, configuration and debugging of the network. The use of optical fiber to connect medium and long-distance network transmission can solve the problem more easily and efficiently.
Optical fiber, short for optical fiber, is a fiber made of glass or plastic that acts as a light-transmitting tool. The transmission principle is 'total reflection of light'.
Compared with traditional network cables, optical fiber communication has the following advantages:
1. Compared with metal network cables, optical fibers made of materials such as glass fibers are lighter in weight and are easy to transport and store.
2. Compared with the network cable that uses electrical signals to transmit data, the optical fiber uses the total reflection of light to propagate the optical signal, and the signal attenuation is small. Therefore, the relay distance of the optical fiber propagation is long, and the long-distance network can be set up.
3. Because the network cable and the optical fiber are made of different materials, the optical fiber uses the reflection of light for information transmission, so it will not be subject to electromagnetic interference from nearby electronic equipment.
4. The transmission bandwidth of the optical fiber is large, and it has the transmission capacity of more communication capacity.
Optical fiber transmission modes can be divided into:
1. Single-mode fiber, whose central glass core is thinner than multi-mode fiber, can only transmit one mode of light. The properties of this fiber mean that it can transmit over long distances.
2. Multi-mode fiber, whose center glass is thick, can transmit multiple modes of light, so this fiber has high transmission efficiency, but it also means that it is not suitable for ultra-long distance transmission.
Commonly used fiber optic connectors
1. SC connector, standard square connector, in-line design, easy to plug.
2. LC connector, similar to SC connector, but smaller than SC
3. FC connector, circular metal connector, the connection method is to rotate and tighten.
Optical module
It is made of optoelectronic devices, functional circuits and optical interfaces. Its function is to convert optical signals and electrical signals to each other, so that the data transmitted by optical fibers can be recognized by general network equipment.
Light delivery cabinet
Outdoor equipment, the optical fiber connects the central computer room and the outdoor network equipment, and the interior is generally a fiber jumper interface without electrical equipment.
Distribution box
Used to store electrical equipment. Generally stored outdoors, used to connect related equipment. The weak current box is used for communication, intelligent control and other equipment. The voltage in the weak current box is a safe voltage not exceeding 36V. The strong electric box is generally connected to electrical equipment with higher voltage.
POE switch
While providing data exchange, it also supports switches powered by network cables. When some devices such as wireless APs need to be installed in high places or other places that are difficult to access power and also need data transmission, POE switches can solve this problem very well.
Fiber Terminal Box
The optical fiber terminal box is the terminal joint of an optical cable, one end of which is an optical cable and the other end is a pigtail, which is equivalent to a device that splits an optical cable into a single optical fiber. It is a user optical cable terminal box installed on the wall. Its function is to provide Fusion splicing of optical fibers and optical fibers, fusion splicing of optical fibers and pigtails , and handover of optical connectors. And provide mechanical protection and environmental protection for the optical fiber and its components.
pigtail
Also known as a pigtail, only one end has a connector, and the other end is a broken end of a fiber optic cable core, which is connected to other fiber optic cable cores by fusion splicing.
jumper
The fiber jumper generally refers to the abbreviation of the fiber jumper. Fiber jumpers are usually optical fibers between fiber distribution frames. The optical fiber from the equipment to the ODF rack is usually called the equipment fiber. Sometimes the communication industry calls optical fibers with connectors at both ends as fiber jumpers.
Fiber Transceiver
A device that converts short-distance network cable electrical signals and long-distance optical signals. When installing, pay attention to the corresponding brand and model, otherwise it may not work properly.