This is a decoder circuit that monitors the rotation of the encoders and communicates the encoder angles to a computer as seen here
http://eksfiles.net/digital-setting-circles/
I have never used it but was told its in working order from the previous owner .
Includes the encoder leads one with a wire that needs resoldering ( the green one in the pic )
Selling AS IS for $45 posted in Oz
PM if interested
Thanks
Zane