RJ-48C CAT5 Wiring Pinout

Posted on August 9th, 2007 by Dennis Little

This is largely a note to myself, but I thought others might find a color code / pinout for the T1 RJ-48C wiring spec handy. This is a crossover cable for a T1 connection, based on the T568A specification (you can use T568B, just make sure you swap colors accordingly):

Pin 1 White/Green – Pin 4 Blue
Pin 2 Green – Pin 5 White Blue
Pin 3 White/Orange – Pin 3 White/Orange
Pin 4 Blue – Pin 1 White/Green
Pin 5 White/Blue – Pin 2 Green
Pin 6 Orange – Pin 6 Orange
Pin 7 White/Brown – Pin 7 White/Brown
Pin 8 Brown – Pin 8 Brown

If you are note sure how an RJ45 connector is numbered, you can reference the wikipedia.org article here.

Filed under: Technology

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3 Responses to “RJ-48C CAT5 Wiring Pinout”

  1. Doug, on August 12th, 2007 at 8:02 am Said:

    For straight-through T1 cables and connectors (*never* wire a jack in the wall as crossover) I always used the T568A/B standards. Only in the case I needed to crossover a T1 cable did I have to worry; and like you said, you only need to remember “1/4, 2/5″.
    That said, there was this one person who could talk for /ever/ about how evil it was to use ethernet standards for T1 cables.. but we never had problems ;)

  2. Dennis Little, on August 12th, 2007 at 9:25 am Said:

    LOL Wiring in-wall as a crossover would certainly baffle the next person to work on that circuit!

  3. Ulises, on August 18th, 2007 at 7:26 pm Said:

    hi nice post, i enjoyed it

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