Twisted-pair are generally made of copper, and a pair of wires are twisted together to decrease interference by adjacent wires. A twisted pair includes two conductors (copper), each with its plastic insulation, twisted together. One of the wires can transfer signals to the receiver, and the difference is used just as a ground reference. The receiver helps the difference between the two.
This means, if two wires are correlated to each other, the noise or crosstalk can affect one wire, and the difference between the two levels would vary. When these wires are twisted, both wires have a similar effect of noise. This way, the receiver receives the correct signal. The number of a twist on the cable defines the quality of signals carried by them.
Therefore, more twisted means better quality signals.
Following are the two types of Twisted-Pair Cables.
A twisted pair includes two insulated conductors twisted together in the spiral form, as shown in the figure. It can be shielded with a plastic cover. The UTP cables are very low-cost and simple to install.
There are the following categories of the unshielded twisted pair cable −
Category1 − Its bandwidth is very low & the data transmission rate 100 kbps. It is used for carrying Analog Signals. It is used in Telephone.
Category2 − Its bandwidth is less than 2 MHz and carries signals at the rate of 2 Mbps. It can take Analog as well as Digital Signals. It is used in LANs as a T1 carrier.
Category3 − Its bandwidth is 2 to 10 MHz. It carries data at the rate of 10 Mbps. It can take digital lines. It is used in LANs.
Category4 − Its bandwidth is 10 MHz to 20 MHz. It transmits data at a rate of 20 Mbps. It can carry digital signals. It is used in LANs.
Category5 − Its bandwidth is 100 MHz. It can carry information at a rate of 100 Mbps. It can carry digital signals used for LANs.
Category6 − Its bandwidth is 200 MHz. It can carry information at a rate of 200 Mbps. It is used for digital signal propagation in LANs.
Category7 − Its bandwidth is 600 MHz. It can carry information at a rate of 600 Mbps. It is used for carrying digital signals is LANs.
In this, each insulated twisted pair are shielded by a metal foil or braided mesh. This mesh is also known as a metal shield. It decreases the interference of the disturbance caused by the surrounding. This property makes the cable bulky and expensive.