Tools

Before starting this lab you need the following: · Two to three foot length of Cat 5 cabling (one per person or one per team) · Four RJ-45 connectors (two extra for spares) · RJ-45 crimping tools to attach the RJ-45 connectors to the cable ends · Ethernet cabling continuity tester that can test straight-through or crossover type cables (T568-A or T568-B). · Wire cutters

Cabling Information

Instructions are provided here for building a T568-A or T568-B cable. Either can be used as long as all connections from the workstation to the wiring closet and terminating electronics (hubs or switches) are consistent. If cables are to be built for an existing network it is important to keep the same standard as already exists. A patch cable that is wired "straight through" will have the same colour of wire on the same pin (1 -- 8) at both ends. A straight through patch cable (T568-A or B) can be used to connect a PC workstation to a wall plate in a work area or it can be used to connect from a patch panel in a wiring closet to a hub or a switch. A PC can also be connected directly to a port on a hub or switch with this cable. If a cable will be used to connect from an "uplink" port on one hub to a "crossover" front port on another hub then a straight through cable should be used

Diagram + Connections

T568-A Cabling

Pin#	Pair#	Function	Wire Colour
1	3	Transmit	White/Orange
2	3	Transmit	Orange/White
3	2	Receive	White/Green
4	1	Not used	Blue/White
5	1	Not used	White/Blue
6	2	Receive	Green/White
7	4	Not used	White/Brown
8	4	Not used	Brown/White

 

T568-B Cabling

Pin#	Pair#	Function	Wire Colour
1	2	Transmit	White/Orange
2	2	Transmit	Orange/White
3	3	Receive	White/Green
4	1	Not used	Blue/White
5	1	Not used	White/Blue
6	3	Receive	Green/White
7	4	Not used	White/Brown
8	4	Not used	Brown/White

Step by Step Instructions

1. Determine the distance between devices, or device and plug, then add at least 12" to it. The maximum length for this cord is 3 m; standard lengths are 6' and 10'.
2. Cut a piece of stranded Cat 5 unshielded twisted-pair cable to the determined length. You will use stranded cable for patch cables because it is more durable when bent repeatedly. Solid wire is fine for cable runs that are punched down into jacks.
3. Strip 2" of jacket off of one end of the cable.
4. Hold the four pairs of twisted cables tightly where jacket was cut away, and then reorganize the cable pairs into the order of the 568-B wiring standard. Take care to maintain the twists since this provides noise cancellation. (Orange pair, green pair, blue pair, brown pair).
5. Hold the jacket and cable in one hand, untwist a short length of the green and blue pairs, and reorder them to reflect the 568-B wiring colour scheme. Untwist and order the rest of the wire pairs according to the colour scheme.
6. Flatten, straighten, and line up the wires, then trim them in a straight line to within 1/2" - 3/4" from the edge of the jacket. Be sure not to let go of the jacket and the wires, which are now in order. You should minimize the length of untwisted wires because overly long sections that are near connectors are a primary source of electrical noise.
7. Place an RJ-45 plug on the end of the cable, with the prong on the underside and the orange pair to the left side of the connector.
8. Gently push the plug onto wires until you can see the copper ends of the wires through the end of the plug. Make sure the end of the jacket is inside the plug and all wires are in the correct order. If the jacket is not inside the plug, it will not be properly strain relieved and will eventually cause problems. If everything is correct, crimp the plug hard enough to force the contacts through the insulation on the wires, thus completing the conducting path.
9. Repeat steps 3 through 8 to terminate the other end of the cable, using the same scheme to finish the straight through cable.
10. Test the finished cable.