There is a foil or braid shield inside the jacket covering all wires (as a group).

Each pair of wires is individually shielded with foil.

Shielded twisted pair cable is available in three different configurations:

Shielded cables can also help to extend the maximum distance of the cables. If you must place cable in environments with lots of potential interference, or if you must place cable in extremely sensitive environments that may be susceptible to the electrical current in the UTP, shielded twisted pair may be the solution. This standard designates which wire goes with each pin inside the connector.ДЄlthough UTP cable is the least expensive cable, it may be susceptible to radio and electrical frequency interference (it should not be too close to electric motors, fluorescent lights, etc.). RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. A slot allows the RJ-45 to be inserted only one way. This is a plastic connector that looks like a large telephone-style connector (See fig. The standard connector for unshielded twisted pair cabling is an RJ-45 connector. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated six categories of wire (additional categories are emerging). The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The cable has four pairs of wires inside the jacket. The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks (See fig. Twisted pair cabling comes in two varieties: shielded and unshielded.

The following sections discuss the types of cables used in networks and other related topics. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network. The type of cable chosen for a network is related to the network's topology, protocol, and size. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. There are several types of cable which are commonly used with LANs. Cable is the medium through which information usually moves from one network device to another.

Cable basics