This is just a short tutorial showing the layout of how standard cable and crossover(null-modem cable) cables are made and the differences between them.

These cables can be purchased at any computer store but why spend the money to buy premade cables while you can make or repair the cables at home or where ever you may be at the time.

Cross over cable
This used when you need to connect two computers together, if a hub is not available at the time, other uses for this cable are connecting two hubs or switches together.
To make this cable one end has to be setup as shown in the crossover layout and the other end has to be the standard layout

Standard cable
This is used for connecting to routers, hubs and switches, cable modem Etc.
To make this cable both ends are the same as shown in the standard layout

List of tools and items you will need
A box of RJ45 connectors( these can be picked up at pretty much any computer store)

A RJ45 crimper (same as above I highly recomend using a crimper instead of using a pair of plyers and a flat screw driver less chance of messing up the connector and having to start over again.)

Cat5 cable (same as above)

What you need to do to get started
Strip about 1" inch of the outter jacket off of the cable being careful not to nick the wires on the inside

Next untwist all the wires so it will be easier to arrange them in the proper order.



Wire standard 568B
top of the RJ45 connector with copper/brass conductors facing you
Code:
    |    Insert    |
    |  Cat 5 cable |
  __|______________|__
  |                   |
  ||¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯||
  ||     wedge       ||
  ||_________________|| 
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  ¯¯¯|¯|¯|¯|¯|¯|¯|¯|¯........Orange with white stripe     
     | | | | | | |...........solid orange
     | | | | | |.............green with a white stripe
     | | | | |...............Solid blue
     | | | |.................blue with white stripe
     | | |...................solid green
     | |.....................brown with a white stripe
     |.......................solid brown
Cross over cable 658A
top of the RJ45 connector with brass/ copper conductors facing you
Code:
    |   Insert     |
    | Cat 5 cable  |
  __|______________|___
  |                   |
  ||¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯||
  ||      wedge       ||
  ||_________________|| 
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  || * * * * * * * * ||
  ¯¯¯|¯|¯|¯|¯|¯|¯|¯|¯........White with a Green stripe     
     | | | | | | |...........Solid Green 
     | | | | | |.............White with a orange stripe
     | | | | |...............Solid Blue 
     | | | |.................White with a blue stripe
     | | |...................Solid Orange 
     | |.....................White with a brown stripe
     |.......................Solid brown
(A good habbit to get into doing, is to double check to make sure that the wires reach the copper or brass connectors at the end and that order of the wires are in the proper order before you crimp the connector.
Happy crimping