Establishing encoder inputs w/o Manual?

I have a drive with no diagram for encoder inputs.
After powering it up I found the following on the encoder connector:

2 pins 2.3v
2 pins 2.4v
2 pins -5v
2 pins Rising Mv
1 pin Rising - Mv

There are also the +5v and 0v pins.
This drive can use absolute encoder or incremental.

I am using the incremental A/A-, B/B-, C/C-.
Anyone have a guess what pins to try for the ABC?

This is a/c drive with encoder input and output. This is for the input.

I checked my working dc servo mill and all the encoder inputs were generating 2v. Looks like the 2.3 & 2.4v are the ABC however I am 2 short.
Not sure what the -5v means. Anyone have a clue?