How do I make a T1/E1 Crossover cable

Required equipment:

• RJ45 crimping tool

• An RJ-45 plug

• Suitable twisted pair cabling such as CAT5
   

A T1/E1 crossover cable has pin 1 routed to pin 4 and pin 2 routed to pin 5. 

 
Pin 1 will be the far left pin when holding the plug with the lock-tab facing away from you. Pin 8 will then be the far right pin.

1 <-> 4
2 <-> 5

The other pairs of the cable should all be routed straight through (the T568A standard may be used as an example for this).

 
This is not compatible with an Ethernet cross-over cable which swaps 1<->3 and 2<-> 6 (and optionally 4 <->7 and 5 <-> 8).