Typical Single Head Mast                                     Typical Dual Head Mast
                                                                                                      Mainline route head over
                                                                                                        Diverging route head

                   Typical multi-head signal bridge                                  Typical single head signal bridge

For those plants with signal heads, there will also be a 10 wire multicolored cable which will connect the 4ASD-4 to a Signal Head board (SHB).

The Signal Head Board (SHB) will have four ports which connect to signals via a RJ-12 cable and a RJ-12 plug.

The color order from left to right with the clip UP is: Blue, Red,Yellow, Green, White and Black. The White and Black are reserved for future use.

The Blue wire of the RJ-12 connects to the white wire of the signal heads and there order is White, Green, Yellow, and Red.