Reverse wiring is generally used for voice application.

* 28AWG (CCA), silver satin jacket
* Terminated with RJ12 (6P6C) plug on both end
* 6 conductor reverse wiring
pin1 -- pin6 (white)
pin2 -- pin5 (black)
pin3 -- pin4 (red)
pin4 -- pin3 (green)
pin5 -- pin2 (yellow)
pin6 -- pin1 (blue)