Wires for Data Networking

Before adding the wires, make sure you plans fit into an overall Network Architecture.

Ethernet

There are  three types of cable defined by EIA/TIA for Ethernet. They are Cat 5, Cat 5E, and Cat 6 (there is also a Cat 7 specification under development). All three cables are capable of running Ethernet at speeds from 10 Mbps to 1 Gbps (a.k.a., gigabit Ethernet). Everything else being equal, the likelihood of obtaining higher speed data throughput: goes up as you go from Cat 5 to Cat 5E to Cat 6.

However, there are a number of other factors that affect the likelihood of obtaining higher data rates:

• The longer the run, the less the likelihood. Even though the specification calls for 100 meters, the likelihood of getting gigabit Ethernet over a given wire goes down as the length increases. In fact, some homeowners prefer to limit their cable runs to 100 feet by creating a second wiring closet to connect to those rooms whose runs are over 100 feet and then run either Cat 5E or fiber Ethernet to that wiring closet. This not only improves their chances of obtaining higher throughput to all rooms, but also saves them money on cabling in that the runs to those far away rooms are now shorter.

• Wires that are bent will have degraded performance. You will want to make sure the person pulling the wire knows what he or she is doing.

• Wires that have been stretched will have degraded performance. This can even happen after the house is build as the house settles. Therefore, it is important to have a little slack in the cable.

Of course the other major factor in choosing the wire is the cost. The cost of Cat 5E is only about one third more than the cost of Cat 5. After adding the cost of installation, this cost difference should be relatively insignificant. However, Cat 6 costs 3 times as much as Cat 5E and can increase your overall cost significantly.

Taking these factors into account, homeowners often choose Cat 5E cable for their data networks because it offers the best cost/performance trade off. Then, they pay the additional amount to have the wires tested. The tests you will want to have performed are listed in Run an Ethernet Cable.

The other choice to make is how to terminate the cable. There are two standards The EIA/TIA-568 standard defines two ways the cables can be terminated. The two ways are called the T568A wiring scheme and the T568B wiring scheme (note that the EIA/TIA-568 “standard” should not be confused with the T568A or T568B  “wiring scheme”). It is unfortunate that the EIA/TIA-568 standard defines the two different wiring schemes (T568A and T568B) because it causes a good bit of confusion among installers and the two schemes are not compatible on the same cable. From a performance perspective, the T568A and T568B wiring schemes behave exactly the same. However, the T568A wiring scheme is much more common in homes and we recommend you run all Cat 5E wire according to the T568A wiring scheme.. We recommend the T568A wiring scheme as it is the most common in buildings today.

WiFi

Wireless Fidelity (WiFi) is a set of specifications for networking via radio waves through the air. WiFi has become so popular that it is sometimes referred to as "wireless Ethernet". There are two key standards today: 802.11b and 802.11g. The former, 802.11b, was the first WiFi introduced and it has become widely popular with some PC interface cards now priced at under $50. The latter, 802.11g, was introduced more recently. It uses a better encoding algorithm to provide better throughput. The latter, 802.11g, is backward compatible with the former, 802.11b. Therefore, you can have both the "b" version interfaces and the "g" version interfaces in the same home.