Twisted pair cable
Twisted Pair cable is used in telecommunications for a variety of purposes. It has also evolved a great deal to improve performance. Twisted pair wiring standards are specified by the ANSI/EIA standard 568. This kind of cabling is probably best recognized for its role in modern Ethernet networks.
Contents
Purpose
Any unprotected wire will tend to pick up electronic interference. This interference comes from radio transmitters, but also from everyday electronic devices such as electric motors and fluorescent lights. Even worse, communications traveling along other nearby wires (which to some extent act as transmitters) can be picked up on separate, insulated lines resulting in crosstalk. This interference is picked up by single strand of wire, and can be disruptive to the device it is connected to. In order to mitigate this problem, this twisted-pair wire was created so that interference is countered by the second line when the first receives it, and vice versa. Then several of these pairs are bundled together (typically four pairs) and covered with a PVC sheath to form standard, Unshielded Twisted Pair wire. To further protect from interference, this twisted pair bundle is sometimes wrapped in an aluminum foil or copper mesh sleeve before it is covered with plastic. This forms what is known as Shielded Twisted Pair.[1] In most cases, unshielded twisted pair is sufficient, and can be used to carry communications over 300 feet.[2][3]
Categories
| Category[4] | Max Date Rate[4] | Purpose[4] |
|---|---|---|
| 1 | 1 Mbit/s | Voice communication |
| 2 | 4 Mbit/s | 4 Mbit/s token ring |
| 3 | 16 Mbit/s | 10BaseT Ethernet |
| 4 | 20 Mbit/s | 16 Mbit/s token ring |
| 5 | 100 Mbit/s (two pairs) | 100BaseT Ethernet |
| 5 | 1,000 Mbit/s (four pairs) | Gigabit Ethernet |
| 5e | 1,000 Mbit/s(two pairs) | Gigabit Ethernet |
| 6 | 1,000 Mbit/s (two pairs) | Gigabit Ethernet |
| 6a | 10,000 Mbit/s | 10 gigabit |
| 7 | 10,000 Mbit/s | 10 gigabit |
Networking
Modern networks typically use at least category 5e or above. Category 5 is also sometimes used, but offers slower service. To offer better service with upgrade capabilities, many networks are now composed of categories 6 or 6a.
When data is moving from one point to another through a network, the transfer can only be performed as quickly as the slowest choke point. For this reason, it is important to maintain consistent cabling throughout a network for optimal efficiency. A single category 5 cable in the wrong place will slow an entire 10,000 Mbit/s network's communication to the Internet or other vital resources to the maximum rate of 100 Mbit/s.
