pin number RJ 11 function RJ 12 function colour code (old) **
colour code (new UTP)
1 none line 3 , tip white * white/green *
2 line 2,  tip line 2, tip black white/orange
3 line 1,  ring line 1, ring red blue/white
4 line 1,  tip line 1, tip green white/blue
5 line 2 , ring line 2, ring yellow orange/white
6 none line 3, ring blue * green/white
* Not present in 4-wire cables
** Second colour is the strip colour