1.For CX E1 cables, use X2 connector and cut off the other side
2.For the connector X2, Pin 1,2 and 4,5 are used. 1, 2 is white and green, they are twisted as 1 pair, this is the RX of the CX E1. The 4,5 are white and blue, they are twisted as another pair, this is the TX of CX E1.
3.There are 4 pairs in one cable, but the other two pair are not used.