CAT 5 cables

Short for Category 5, network cabling that consists of four twisted pairs of copper wire terminated by RJ45 connectors. Cat-5 cabling supports frequencies up to 100 MHz and speeds up to 1000 Mbps. It can be used for ATM, token ring, 1000Base-T, 100Base-T, and 10Base-T networking.

Computers hooked up to LAN s are connected using Cat-5 cables, so if you're on a LAN, most likely the cable running out of the back of your PC is Category 5.

Cat-5 is based on the EIA/TIA 568 Commercial Building Telecommunications Wiring Standard developed by the Electronics Industries Association as requested by the Computer Communications Industry Association in 1985.

568-B Wiring (RJ-45) .

568-A Wiring (RJ-45)

<RJ-45 Pins 1-8 Facing Up>
1 2 3 4 5 6 7 8
. . . . . . . .
. . . .
. . . .
. . . .
. . . .
Orange pair 2 . Blue pair 1 Brown pair 4
<Green Pair 3>

568B Wiring
Pair # Wire Pin #
1 - White/Blue White/Blue 5
Blue/White 4
2 - White/Orange White/Orange 1
Orange White 2
3 - White/Green White/Green 3
Green/White 6
4 - White/Brown White/Brown 7
Brown/White 8

568 B Diagram

<RJ-45 Pins 1-8 Facing Up>
1 2 3 4 5 6 7 8
. . . . . . . .
. . . .
. . . .
. . . .
. . . .
Green pair 2 . Blue pair 1 Brown pair 4
<Orange Pair 3>

568A Wiring
Pair # Wire Pin #
1 - White/Blue White/Blue 5
Blue/White 4
2 - White/Green White/Green 1
Green/White 2
3 - White/Orange White/Orange 3
Orange/White 6
4 - White/Brown White/Brown 7
Brown/White 8

568 A Diagram

Notes for wiring diagrams above:

1. For patch cables, 568-B wiring is by far, the most common method.
2. There is no difference in connectivity between 568B and 568A cables. Either wiring should work fine on any system*. (*see notes below)
3. For a straight through cable, wire both ends identical.
4. For a crossover cable, wire one end 568A and the other end 568B.
5. Do not confuse pair numbers with pin numbers. A pair number is used for reference only (eg: 10BaseT Ethernet uses pairs 2 & 3). The pin numbers indicate actual physical locations on the plug and jack.

See Also: