Birds and Bees (Plugs vs. Jacks)


     The EIA/TIA specifies an RJ-45 (ISO 8877) connector for Unshielded
     Twisted Pair (UTP) cable.  The plug is the male component crimped
     on the end of the cable while the jack is the female component in
     a wall plate or patch panel, etc.  Here is the pin numbering to
     answer the question, where is pin one?

  Plug                          Jack
  (Looking at connector          (Looking at cavity
   end with the cable             in the wall)
   running away from you)

      ---------- /                   ----------
     | 87654321 |                   | 12345678 |
     |__      __|/                  |/_      /_|
        |____|                         |/___|

Ethernet 10Base-T Cabling

2.1 Ethernet 10Base-T Straight Thru patch cord (T568B colors);

         RJ45 Plug        RJ45 Plug
         =========        =========
         /--T2  1  ... White/Orange .... 1  TxData +
   pair2 \--R2  2  ... Orange .......... 2  TxData -
        /----------T3  3  ... White/Green ..... 3  RecvData +
       /           R1  4      Blue              4
       \  pair3    T1  5      White/Blue        5
        \----------R3  6  ... Green ........... 6  RecvData -
     T4  7      White/Brown       7
     R4  8      Brown             8

     12.2 Ethernet 10Base-T Crossover patch cord;
    This cable can be used to cascade hubs, or for connecting
    two Ethernet stations back-to-back without a hub (ideal for
    two station Doom!)  Note pin numbering in item 10.0 above.

     RJ45 Plug  1 Tx+ -------------- Rx+ 3  RJ45 Plug
         2 Tx- -------------- Rx- 6
         3 Rx+ -------------- Tx+ 1
         6 Rx- -------------- Tx- 2

     12.3 Ethernet 10Base-T to USOC Crossover patch cord;

      RJ45 8-pin Plug  1 ---White/Orange--- 2  USOC 6-pin Plug
    ^           2 ------Orange------ 5       ^
         3 ---White/Green---- 1
         6 ------Green------- 6

Crossover Implementation

   A simple way to make a crossover patch cable is to take a 
   dual-jack surface mount box and make the crossover between 
   the two jacks. This allows using standard patch cables, and 
   avoids the nuisance of having a crossover cable find its way 
   into use in place of a regular patch cable.

     12.5 Stranded Patch Cables
   The color code used in stranded patch cables is different from 
   solid-conductor cables. For NorTel Digital Patch Cable (DPC), 
   the coding is;
   Pair 1: Green & Red
   Pair 2: Yellow & Black
   Pair 3: Blue & Orange
   Pair 4: Brown & Gray

Category Specifications

     EIA/TIA Category Specification provide for the following cable
     transmission speeds with specifications (Note prior to Jan94
     UL and Anixter developed a LEVEL system which has been dropped
     or harmonized with the CATEGORY system);

 Category 1 = No performance criteria
 Category 2 = Rated to 1 MHz (used for telephone wiring)
 Category 3 = Rated to 16 MHz (used for Ethernet 10Base-T)
 Category 4 = Rated to 20 MHz (used for Token-Ring, 10Base-T)
 Category 5 = Rated to 100 MHz (used for 100Base-T, 10Base-T)

     UL LAN Cable Certification Program - Underwriters Laboratories
     publication 200-120 30M/3/92, 1992 [characteristics of Cat 3-5 UTP]