Wiring standard / Internet and Networking

Wiring standard :- It is important to understand the order of the wires within the RJ-45 connector for both the network +exam and in the real world if you intend on creating (also known as crimping) your own cables. Let's start with some basics of comparing a straight-throughbcable with a crossover cable.            Straight-through cables:- CAT 5 UTP cabling usually uses only four wires when sending and receiving information on the network. The four wires of the eight that are used wires 1,2,3 and 6.figure 1-18 shows 6 meaning of the pins on a computer and the pins on a hob(or switch),which is what you typically will be connected the computers to. When you configure the wire for the same pin at either end of the cable, this is known as a straight- through cable.
Table 1-2
Different UTP category cabling 

You will notice in the figure that wires 1and 2 are used to transmit data (TX) from the computer, while wires 3 and 6 are uesd to the receive information (RX) on the hob via wires 1 and 2.This is important because we want to make sure that data that is sent from the computer is received at the network hub.  We also want to make sure that data sent from the hub is received at the computer,  so you will notice that the transmit pins (TX)  on the hub are connected to receive pins (RX)  on the computer through wires 3 and 6.  This will allow the computer to receive information from the hub.  The fast thing to note that pin 1 on the computer is connected to pin 1 on the hub by the same wire,  this the term straight - through.