Recording the pinouts for Cat5 RJ-45 connectors, for straight thru and crossover. They are different than I expected. The two links have colored sketches which may be easier to understand.

I wasn't getting a decent blue in the 5th and 6th lines of this table (at NCACC using IE) — it looked green, even though I was using the same color code as elsewhere. Perhaps related to this, on Mozilla, the second cell in the 5th line is blank (should say "Blue" in white text on a blue background). At home, on konqueror, the blue looked OK, but I had changed to a different blue (while still at NCACC, IIRC) Hmm, maybe I accidentally pasted an extra # in front of the color (which I did a few moments ago when pasting a brown code, the color appeared blue — I guess sometime I'll have to go back and try that blue. (And I may want a lighter blue while I'm at it, the blue looks almost black.)

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Notes

Note that the pinout according to the standard is not what I expected. Note the splitting of pair 3 (568B pinout) or pair 2 (568A pinout). What I was doing works, but I've only used it in 10 MBPS networks, I had better switch to the standard for my 100 MBPS links.

To make a standard (straight thru) cable, use the 568B pinout on each end.

To make a crossover cable, use the 568A on one end and the 568B on the other end.

Because the 568B pinout is used on both ends of a straight thru connection, I show the 568B pinout first.

Looking from the top (the surface opposite the plastic latch), with the connection (open end of the connector) pointed to your right, you can read from top (pin 1) to bottom (pin 8), just the way the tables are laid out.

If you only have four conductor cable, pins 1 (Rc+), 2 (Rc-), 3 (Tx+), and 6 (Tx-) are the essential pins. The Tx+ and similar designations are misleading, clearly what is transmit on one end is receive on the other end.

568B Pinout

568B Pinout (below): For both ends of a straight thru cable — View with latch down

Cable End	Color	Pair	Pin
	White-Orange	Pair 2	1
C	Orange	Pair 2	2
A	White-Green	Pair 3	3
B	Blue	Pair 1	4
L	White-Blue	Pair 1	5
E	Green	Pair 3	6
	White-Brown	Pair 4	7
	Brown	Pair 4	8

568A Pinout

568A Pinout (below): For one end of a crossover cable — View with latch down

Cable End	Color	Pair	Pin
	White-Green	Pair 3	1
C	Green	Pair 3	2
A	White-Orange	Pair 2	3
B	Blue	Pair 1	4
L	White-Blue	Pair 1	5
E	Orange	Pair 2	6
	White-Brown	Pair 4	7
	Brown	Pair 4	8

Resources

See Resource Recommendations. Feel free to add additional resources to these lists, but please follow the guidelines on ResourceRecommendations including Guidelines_for_Rating_Resources.

Recommended

• (rhk) EIA/TIA 568A & 568B Standard; ; —
• (rhk) the 5-in-1 network admin's cable; — "ethernet / crossover / modem / null modem / Cisco console"
• (rhk) [[][]]; ; —

Contributors

• () RandyKramer - 13 May 2003
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