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Howto build your E1<>RJ45 cable

We used a Cat-7 Ethernet cable to build our E1<>RJ45 cable to connect the BTS with the BSC.

Things you need:
  • one Cat-7 Ethernet cable
  • two twinax plugs (BR2)
  • some heat shrink tube
  • soldering-iron
  • multimeter (optional)
  • a sharp knife :)

Step-by-step guide

One

Take your cable and cut off one of the RJ45 connectors. Now use a ruler and make a slice so you can strip around 15 cm from your cable.

Two

Split the wires from your cable. We need pin 1 and 2 for RX and pin 4 and 5 for TX, Use a Multimeter to determine the correct pairs. Cut off the other wires we do not need them (yet).

Three

Sort your twinax plugs to make sure you build them in the right order. ;)

We used heat shrink tube to stabilize our cable around the plugs.


Four

Now you can put everything on the first part of the cable and assemble it. Use a soldering-iron to fixate each of the two pins of the plug with your wires. You do not have to worry about the polarity inside the twinax plug.

Five

Repeat step three and four to build the second plug.

Done

Detailed pinout

A detailed pinout for your reference:


Signals on the RJ45 plug:
             ++++++++++ 
            / /               / /|
           / /               / / |
          / /+++++++_/ /  |
         / ++++++++  /   |
        / / / / / / / / / / /    |
       / / / / / / / / / / /    / 
      / /_/_/_/_/_/_/_/_/ /    / 
      | | | | | | | | | | |   /
      | |8|7|6|5|4|3|2|1| |  /
      | |_|_|_|_|_|_|_|_| | /
      |+++++++++_|/
            |      |/
            \+++/

    1 = RX1
    2 = RX2
    3 = NC
    4 = TX1
    5 = TX2
    6 = NC
    7 = NC
    8 = NC

Signals on the twinax plugs:

     E1 Transmitter:
           +_            
       .-_   '@-.  
     .'           @. 
    /     1      2  \
   :    ##     ##    ;
   |    ##     ##    |
   :                 ;
    \ ############# /
     @. ######### .'
       @-.++_.-'

    1 = TX1
    2 = TX2

     E1 Receiver:
           +_            
       .-_   '@-.  
     .'           @. 
    /     1      2  \
   :    ##     ##    ;
   |    ##     ##    |
   :                 ;
    \ ############# /
     @. ######### .'
       @-.++_.-'

    1 = RX1
    2 = RX2

      Note: The drawings are showing the plugs point of view. 
      Note: This is a differential connection with symetric signals
            so you do not have to care about the polarity.

Cable connection on the BS11:

  ---~++++_---
 /        12            \
 \        oo   oo       /
  ---~|+++_|--- 

    1 = RX (connect E1 Transmitter to that port)
    2 = TX (connect E1 Receiver to that port)

IMG_0960-1.JPG (620 KB) kenny, 04/08/2009 06:29 PM

IMG_0960-2.JPG (619 KB) kenny, 04/08/2009 06:31 PM

IMG_0960-4.JPG (659 KB) kenny, 04/08/2009 06:31 PM

IMG_0960-5.JPG (586 KB) kenny, 04/08/2009 06:32 PM

IMG_0960-7.JPG (468 KB) kenny, 04/08/2009 06:32 PM

IMG_0960-9.JPG (580 KB) kenny, 04/08/2009 06:33 PM

IMG_0960-11.JPG (663 KB) kenny, 04/08/2009 06:34 PM

IMG_0960-12.JPG (401 KB) kenny, 04/08/2009 06:34 PM

IMG_0960-17.JPG (692 KB) kenny, 04/08/2009 06:35 PM

IMG_0960-19.JPG (368 KB) kenny, 04/08/2009 06:35 PM

IMG_6379-1.JPG (519 KB) kenny, 04/08/2009 07:24 PM