Need help with Rotary position switch

Good morning everyone.
I have a Fry ET18 lathe I am in the process of updating. I am using a Mesa 7i77 and 6i25 board. The lathe has rotary switches for both feed and speed overrides, which I would like to use. The problem is that I cannot find any documentation on the switches, and therefore dont know how to wire them into the Mesa
I attached the factory wiring diagram, and a few pictures of the switches. They are 15 position switches, have 5 wires coming out of them, and appear to be '4 deck' switches from what I can tell. The numbers on the back of the switches are C4D0115N-4471 and I think they are made by Electroswitch. The only documentation I was able to find is from Mouser (here is the link:  www.mouser.com/datasheet/2/128/c4-2309149.pdf ) but I still could make sense of how the wiring would work...with only 5 wires, how is it possible to make 15 different unique positions??? I am assuming at least one of the wires must be DC power?

Thanks folks!


EDIT:
I now believe it is possible to have 15 combinations with one pole and 4 outputs. I have attached that image as well. 

The switch is possibly binary encoded so there may be one common
connection and 4 outputs. Unless you have further details on the
switch, you will likely need to determine its operation with an
ohmmeter.

 

The switches seem to be generic wafer switches, so as PCW says, you might need to figure out the wiring/encoding with a multimeter.

15 positions and 5 wires hints at binary encoding but it could be straight binary or gray-coded.

One wire will be common, and then others will be connected to that (probably through diodes) . If this is the case then you would need to set your multimeter to diode-check mode as the ususal voltage used to measure continuity is too low to overcome the forward voltage drop in diodes.

All you really need to do is figure out whether the common wire is a ground or a voltage. With the multimeter in voltage mode look for a wire that stays at a constant voltage WRT ground regardless of the position of the knob.

andypugh wrote:

All you really need to do is figure out whether the common wire is a ground or a voltage. With the multimeter in voltage mode look for a wire that stays at a constant voltage WRT ground regardless of the position of the knob.

I meant to go on to say that, once the inputs are connected to inputs in LinuxCNC we can work out the encoding then. 
 

Sounds good. Ill start poking around with a multimeter this evening.

This may help
forum.linuxcnc.org/show-your-stuff/32029...build?start=20#85279