It may be a bit confusing, I used the colors that come in a CAT5 cable, so I had to double up a couple of colors, the dotted lines are the white striped wires. The center A is internally connected to 1-3, depending on the switch position. B goes to 4-6, C to 7-9 and D to 10-12. So the first position activates 1,4,7 & 10. The 2nd activates 2,5,8 & 11 and the 3rd 3,6,9 & 12. (The way I hooked up + & - to A-D isn't the same as BH used, but It worked for me)