Nowadays, no matter we are working or studying, we can’t live without the Internet. Can you imagine what the world would be like if the Internet were to suddenly go offline one day?
LAN (Local Area Network) is the most common type of network. To connect to a LAN, network cable is essential. There are three kinds of cable in LAN: twisted pair cable, coaxial cable and fiber optical cable. Here we will only introduce twisted pair cable.
What is a twisted pair cable?
Twisting two insulated copper wires with each other at a certain density can reduce the degree of signal interference. The radio waves radiated by each wire during transmission will be canceled by the radio waves emitted by the other wire. The name “twisted pair” also comes from this.
Twisted pair is generally made of two 22AWG-26AWG insulated copper wires intertwined with each other. Different pairs have different twisting lengths. Generally speaking, the twisting length is within 38.1cm to 14cm, twisting in the counterclockwise direction.
How to distinguish different types of twisted pair?
Twisted pair can be divided into STP (Shielded Twisted Pair) and UTP (Unshielded Twisted Pair). STP has a layer of metal isolation film inside the twisted pair, which can reduce electromagnetic interference during data transmission, so its stability is higher than UTP. Meanwhile, STP cost will be higher than UTP.
Shielded twisted pair is further subdivided into U/FTP, F/UTP, F/FTP, S/FTP, etc. according to cable shielding and pair shielding.
Common types of twisted-pair cables are category 3 (Cat.3), category 5 (Cat.5) and enhanced category 5 (Cat.5e), category 6 (Cat.6) and augmented category 6 (Cat.6a), and category 7 (Cat.7). The former has a thin wire diameter and the latter has a thick wire diameter.
Cat.3 cable is used for voice transmission and data transmission with a maximum transmission rate of 10Mbps and a transmission frequency of 16MHz.
Cat.5 cable increases the winding density, coats a high-quality insulating material, and has a transmission rate of 100MHz. It is used for voice transmission and data transmission with a maximum transmission rate of 100Mbps.
Cat.5E cable has less attenuation, less crosstalk, and has a higher ratio of attenuation to crosstalk (ACR) and signal to noise ratio (Structural Return Loss), smaller delay errors, and performance has been greatly improved. The maximum transmission rate is 150~155Mbps.
Cat.6 cable transmission frequency is 1MHz~250MHz, and the total attenuation crosstalk ratio (PS-ACR) of the Cat.6 wiring system at 200MHz should have a large margin. It provides twice the bandwidth of Cat.5e. The transmission performance of Cat.6 cabling is much higher than the Cat.5 standard, and it is most suitable for applications with transmission rates higher than 1Gbps.
Cat.6A cable is an improved version of Cat.6 cable, which is mainly used in Gigabit networks. In terms of transmission frequency, it is also 200~250 MHz, which is the same as the Cat.6 cable. The maximum transmission speed can also reach 1 000 Mbps, but there is a big improvement in crosstalk, attenuation, and signal-to-noise ratio.
Cat.7 cable is a shielded twisted pair, so its transmission frequency can reach at least 500 MHz, which is more than twice that of Cat.6 and Cat.6A, and the transmission rate can reach 10Gbps. It is mainly to adapt to the application and development of 10 Gigabit Ethernet.
In addition, the twisted pair cables can be divided into Indoor cable and Outdoor cable according to the different apllication range. The biggest difference between them is the outer jacket material: PVC for indoor cable, PVC+PE for outdoor cable. Normally, the indoor cable outer jacket can be grey, blue, yellow etc. colors, but outdoor cable is black.
