Here's what I have to work with...
http://imgur.com/a/uIj9bI think that the unit was originally intended as a wall-mount timecard entry system or something.
I'm pretty excited because the actual keypad has everything I wished my last project (Goldtouch lobotomy) had. This keypad has 35 plate-mounted Cherry MX black switches, red LEDs, and per-key backlighting thanks to a set of I2C I/O extenders.
I plan on removing the bottom MCU board and replacing it with a Teensy 2.0++ and TMK.
In case anyone finds another one of these, here's what I've done to reverse engineer it.
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The I2C extenders need to be mapped, still, but they have sequential I2C addresses (0b000 to 0b100).
Keypad-to-MCU Cable Pinout:
01 - VCC (+5V)
02 - VCC (+5V)
03 - SCL (U8p14)
04 - SDA (U8p15)
05 - Col #1 (U8p21)
06 - Col #2 (U8p22)
07 - Col #3 (U8p23)
08 - Col #4 (U8p24)
09 - Col #5 (U8p25)
10 - Row #1 (U8p39)
11 - Row #2 (U8p38)
12 - Row #3 (U8p37)
13 - Row #4 (U8p36)
14 - Row #5 (U8p35)
15 - Row #6 (U8p34)
16 - Row #7 (U8p33)
17 - Row #8 (U8p32) * Keypad does not have Row #8, but MCU supports it
18 - GND
19 - GND
20 - Shield
RJ-45 Pinout:
01 - RS-422 A
02 - RS-422 B
03 - VCC (+5V)
04 - VCC (+5V)
05 - VCC (+5V)
06 - GND
07 - GND
08 - GND