Cellular Network Infrastructure » Radio Access Network » OsmoBSC

== 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.

[[Image(IMG_0960-1.JPG, 15%)]] [[Image(IMG_0960-2.JPG, 15%)]]

'''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).

[[Image(IMG_0960-4.JPG, 15%)]] [[Image(IMG_0960-5.JPG, 15%)]] [[Image(IMG_0960-7.JPG, 15%)]]

'''Three:'''

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

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

[[Image(IMG_0960-9.JPG, 15%)]] [[Image(IMG_0960-11.JPG, 15%)]] 

[[Image(IMG_0960-12.JPG, 15%)]] [[Image(IMG_0960-17.JPG, 15%)]]

'''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.

[[Image(IMG_0960-19.JPG, 15%)]]

'''Five:'''

Repeat step '''three''' and '''four''' to build the second plug.

'''Done.'''

[[Image(IMG_6379-1.JPG, 15%)]]

== 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:

  ~~~~~~~_________~~~~~~

 /        oo   oo       \

 \        12            /

  ~~~~~~~|_______|~~~~~~ 

	1 = RX (connect E1 Transmitter to that port)

	2 = TX (connect E1 Receiver to that port)

}}}