Monday, 23 February 2015

Twisted Pair Cabling


In its simplest form, the twisted pair cable contains two copper strands intertwined twisted and covered with insulator.

There are generally two types of twisted pair:

Shielded pairs (STP: Shielded Twisted Pair)
Unshielded pair (UTP: Unshielded Twisted-Pair).

A cable is often made from several twisted pairs grouped and placed inside of the protective sheath. Striping helps to remove noise due to contiguous pairs or another source (motors, relays, transformers).
Twisted pair is therefore suitable for local networking a small park with a limited budget and simple connections. However, over long distances with high data rates it does not guarantee data integrity (that is to say, the transmission without data loss).

Unshielded twisted pair (UTP)

UTP obeys the 10BaseT specification. This is the twisted pair type most used and most widespread for local networks. Here are some features:

Most telephone installations use UTP cable. Many buildings are pre-wired for this type of installation (often in sufficient numbers to meet the future needs). We must be careful, however, to the number of twists and other electrical characteristics required for quality data transmission.

The major problem is that the UTP cable is particularly subject to interference (a signal line mixing with those of another line). The only solution lies in the armor.

The shielded twisted pair (STP)

The STP (Shielded Twisted Pair) uses a higher quality copper sheath and more protective than the jacket used by UTP cable. It contains a shroud between the pairs and around pairs. In the STP cable, copper son of a pair are themselves twisted, which provides STP cable excellent shielding, that is to say, better protection against interference). On the other hand it allows faster transmission and a longer distance.