Networking

UTP implementation

EIA/TIA specifies an RJ-45 conector for UTP cble. The letters RJ stand for registered jack and the number 45 refers to a specific wiring sequence. The RJ-45 transparant and connector show eight colored wires. Four of the wires, T1 through T4, carry the voltage and are called tip. The other four wires, R1 through R4 are grounded and are called rinf. Tip and ring are terms that originated in the early day of the telephone. Today, these terms refer to the positive and the negative wirein a pair. The wires in the first pair in the cable or a connector aredesignated as T1 and R1. The second pair is T2 and R2, the third is T3 and T3, and the fourth is T4 and T4.

The RJ-45 connector is the male component, which is crimped on the end of the cable. When a male connector is viewedfrom the front, the pin location are numbered on the left to 1 on the right as seen in figure.

The jack is the female component in a network device, wall outlet, or patch panel as seen in figure follow :

Figure follow show the punch-down connection at the back of the jack where the Ethernet UTP cable connects.

For electricity to run between the connector and the jack, the order of the wires Must follow T 568A or T 568B color code found in the EIA/TIA-568-B.1 stadard..

To determine the EIA/TIA category of cable that should be used to connect a device, refer to the documentation for that device or look for a label on the device near the jack. If there are no labels or documentation available, use category 5E or greater as higher categories can be used in place of lower ones. Then determine whether to use straight-through cable or a crossover cable.

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Networking Terminology

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Businesses needed a solution that would successfully address the following three problem :

How to avoid duplication of equipment anf resources
How to communicate efficiently
How to set upand manage a network.

One early solution was creation of local-area network (LAN) standard. LAN standard provided an open set of guidelines that companies used to create network hardware and software. As a result, the equipment from different companies besame compatible. Thie allowed for stability in LAN implementations.

In a LAN system, each departement of the company is a kind of electronic island. As the use of computer in bussinesses grew, LANs become insufficient.

A new tecnology was necessary to share information efficiently and quickly within a company and between businesses. The solution was the creation of metropolitan-area networks (MANs) and Wide-area Networks (WANs).

Figure summarizes the relative size of LANs and WANs.