This converts pre-modern keyboard protocols into modern USB using TMK Keyboard Firmware Collection.
You can buy assembled converter here. https://geekhack.org/index.php?topic=72052.0
2016/07/03 Rev 2.4 Changed foot print of USB microB and Xtal 2015/09/29 Rev 2.2 Changed LED footprint
See this for supported protocols.
MiniDIN 6P
MiniDIN 4P
MiniDIN 7P
MiniDIN 8P
MiniDIN 8P
MiniDIN 5P
Rev1 has lands for MiniDIN and IO pads for other interface than MiniDIN. With wire jumpers it can support many protocols. It uses Atmel AVR ATmega32U4.
Rev2 is smaller and supports only protocols which uses MiniDIN connector and can be configured with solder jumpers on bottom of the board. It uses Atmel AVR ATmega32U2.
Fixed misaligned pins of Mini DIN connector, clearance of solder mask and silk prints.
