Look at this beauty. It's an LPFK by IBM. A "lightable programmable function keyboard" normally attached to a 5080 IBM graphics card for CAD purposes on RS/6000 machines running AIX. The IT-department of the University of Karlsruhe threw it away. i found the protocol in ancient ibm aix sources.

Just cut off the 8-pin AIX connector, and solder a USB-to-serial convertor to it that talks rs232-levels (±16V). the power consumption with all leds lit is around 700mA.

orange    +5V
black     +5V
green     gnd
white     gnd
red       tx
grey      rx
Serial communication is easy: 9600 8O1 and the following commands:

pc -> lpfk
01	   reset
08         enable
09	   disable
94aabbccdd set leds

lpfk -> pc
00..1f     keypress
80         94 command received failed, retry
81         94 command received ok
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