Home Area Networks and IPTV

Chapter 4

Home Area Network Technologies

4.1. Copper pair cables

Copper pair cables are used for short distances, notably for constructing home networks, and are mainly dependant on crosstalk in its different forms.

Table 4.1. Crosstalk in copper pair cables

Type of crosstalk	Denomination	Physical phenomena
Local crosstalk or near end crosstalk	NEXTNear End Cross Talk	Interference from another conductor at the same extremity
Far end crosstalk	FEXTFar End Cross Talk	Interference from another conductor at the opposite end
Total local crosstalk	PSNEXTPower Sum Near EndCross Talk	Sum of crosstalk affecting a conductor
Exogeneous crosstalk	Alien NEXT	Interferences betweencables from the samestrand

Table 4.2. Different types of pair cables

The technology used to combat crosstalk rests on the use of several pairs, which are twisted in a way calculated to reduce or to eliminate undesirable emission and reception.

As the binary bit rate increases, the more the pair behaves like an antenna susceptible to emission or reception of electromagnetic waves.

In addition, the connectors become a source of defect when the bit rate increases, under the effect of several phenomena related to too small a distance between terminals. This is why 10 GbE category cables cannot use RJ45 connectors.

In the United States, home area networks cabled with multi-pairs are most often limited to category ...