Views: 141 Author: Site Editor Publish Time: 2020-05-25 Origin: Site
In network transmission, the media used for network transmission can not be ignored. We usually call it network cable. At present, the common network cable is thin twisted pair cable, fiber optical cable and optical cable. The following describes the differences between twisted pair cable and fiber optical cable.
Fiber optical is a new generation of transmission medium. Compared with copper twisted pair, the fiber optical has greatly improved in security, reliability and network performance. In addition, the bandwidth of fiber optical transmission is much larger than that of copper twisted pair, and its maximum connection distance is more than two kilometers, which is the inevitable choice to build a large-scale network. Due to the advantages of good anti electromagnetic interference, strong confidentiality, high speed and large transmission capacity, optical cable is also more expensive and rarely used in domestic occasions.
At present, there are two common types of fiber optical, single-mode fiber optical and multi-mode fiber optical (the so-called "mode" refers to a beam of light entering the fiber optical at a certain angle). The multi-mode fiber optical is generally used for network connection in the same office building or relatively close area. The single-mode fiber optical is usually used to connect office buildings or geographically dispersed networks because of its higher data quality and longer transmission distance. If the fiber optical is used as the transmission medium of the network, the optical transceiver and other equipment need to be added, so the cost investment is larger and less used in general applications.
The twisted pair is a kind of flexible communication cable, which contains pairs of insulated copper wires. It is characterized by low price, so it is widely used, such as common telephone lines. According to the difference of the maximum transmission rate, the twisted pair can be divided into CAT3, CAT5 and super CAT5e.
The transmission frequency of the CAT3 is 16mhz, and the maximum transmission rate is 10Mbps. It is mainly used in voice, 10mbit/s Ethernet and 4Mbit/s token ring.
The highest frequency bandwidth of CAT5 is 100MHz, and the highest transmission rate is 100Mbps. It is used for voice transmission and data transmission with the highest transmission rate of 100Mbps. It is mainly used for 100BASE-T and 1000BASE-T networks, which is the most commonly used Ethernet cable.
The CAT5e has the characteristics of small attenuation and less crosstalk, and has higher ACR and SNR, smaller delay error, and greatly improved performance. It is mainly used for Gigabit Ethernet (1000Mbps).
The twisted pair can also be divided into shielded twisted pair (STP) and unshielded twisted pair (UTP). There is a metal shield between the twisted pair inside the STP and the outer insulating envelope. Although STP has a low speed (only 4MB/s), it has better anti-interference than UTP, so the price is much higher than UTP.
UTP is a kind of data transmission line, which is composed of four pairs of transmission lines with different colors. It is widely used in Ethernet and telephone lines. UTP has the following advantages: 1. No shielding jacket, small diameter, low cost. 2. Light weight, easy to bend and install. 3. Little or no crosstalk. 4. It is flame retardant. Therefore, UTP is widely used in PDS.