Twisted Pair Cable:
In 2004 the most common cable is Twisted Pair cable. Twisted pair cable will contain 8 Pieces of wires colored Green, Orange, Blue and Brown and 4 pieces are white. Each white color is twisted with other 4 colors to make 4 pairs at a slightly different ratio than the other pairs. This is done to reduce the effects of cross talk. Cross talk is when the signal in one pair of wires has an unwanted effect on other wires within the same cable.
Twisted Pair are two types
a) UTP (Unshielded Twisted Pair)
b) STP (Shielded Twisted Pair)
IBM produced STP for its use.
What we have learnt is UTP and in STP there is an Aluminum or Polyester coating over this 4 pairs cable to save cable from Electromagnetic Interference.
But UTP is most used cable in LAN networks. Day by day developing its category.
The categories are:
* CAT 1: Used for voice or alarm signal in Analog telephone. Data Rate less than 0.1 Mbps.
* CAT 2: Originally used in T-lines (We will learn later about T-lines). Data Rate 2 Mbps.
* CAT 3: Bandwidth 10 Mbps
* CAT 4: Bandwidth 20 Mbps
* CAT 5: Bandwidth 100 Mbps. Range-100 meters
* CAT 5e: It improves the transmission speed and twist ratio of the pairs. Designed for less cross-talk between pairs. Data Rate 125 Mbps. Cat 5e cable ranges are still limited. That is maximum of 100 meters in length (normal practice is to limit fixed ("horizontal") cables to 90 m to allow for up to 5 m of patch cable at each end, this comes to a total of the previous mentioned 100m maximum).
* CAT 6: The cable must be tested at a 200-Mbps Data Rate.The other major difference. In this cable, internally it has a ‘plus’ type plastic so each pair can remains in a barrier.
* CAT 7: Sometimes called SSTP (Shielded screen twisted-pair). Each pair is individually wrapped in a helical metallic foil followed by a metallic foil shield in addition to the outside sheath. The shield decreases the effect of cross-talk and increases the data rate. Data rate is 600 Mbps.
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