Encoder help?

Hello everyone,

I am extremely new to the CNC world. I have obtained a Techno Isel Davinci 3-Axis CNC router from a local High School auction. Upon taking it all home, reading through the documentation and inspecting everything, the main control board has been fried somehow. The servo motors and everything else looks very good, with little usage.
I have been learning and reading tons of data on the whole thing and have come to the conclusion that my best bet is to rebuild the controls.

I have decided to use Gecko G320X drives and the power supply from the original system. Due to my occupation, most all of this stuff makes perfect scenes… for the most part. My biggest issue is regarding the encoders.

I have a basic understanding of the encoders, the basics of how they
work, and what they are used for, but my question is regarding wiring and a few functions of the encoders.
After carefully disassembling the servo and covers to get part numbers, it looks like I have Renco Encoders, P/N 77822-033, D/C 9845. After looking online (a lot), I think that they are RM15's. Looking at the Techno Isel's manuals that came with the unit, the following pin-out was used in their configuration:

1 & 15 are jumped together as the E-stop loop.
2, is the yellow wire on the encoder and is used as the A encoder channel.
3, is the blue wire and is used as the B encoder channel.
4, is the brown wire and is used as the "I" Index encoder channel.
5, is the red wire and is used as the 5v+.
6, is tied to a limit switch.
7, 8, 9, are not used
10, is the encoders white wire and is used as the "not" A (or A with a line over it).
11, is the green wire and is used as the "not" B.
12, is the orange wire and is used and the "not" I.
13, is black and is used as the encoder ground.
14, is tied to the other side of the limit switch.

Can someone please help me understand what 10, 11, and 12 are used for and also what is the Index used for. I THINK that it is used for/as the home position, but I am not sure. Reading the documentation for the Gecko drive, I don't see a place to terminate them. Do they need to be used?

I am also using a Breakout combo board from sound logic, which is
supposed to be a good fit with Mach 3 and the Gecko drives.
The breakout board doesn't say anything about the Index function either.

Also, are these encoders going to work for my project? I think I am going to have to have an external power supply too.

Thanks

Eric