The whole thing is converting the proprietary Line6 protocol into a standard MIDI one. For this task you need a micro controller with some software to interface between the Line6 and Midi. As a micro controller an Arduino 1280 EVM is used (about 25 EUR).
The controller board from mDan is interfacing between the Line6 Shortboard, MIDI and the Arduino micro controller (opto-coupler, signal levels etc.). Also the software for the micro controller is from mDan.
So the set up is as follows (ignore dots):
Line 6 Shortboard ---(RJ45)---> mDan's Interface Board ---(MIDI)---> Kemper KPA
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......................................................Arduino 1280 uC EVM
So you need:
- Shortboard
- mDan's Interface Board
- Arduino 1280 uC
- power supply, 9V
- RJ45 and MIDI cable
- some kind of housing or case to put in the uC and the interface board.
Alternatively, you can directly include the Arduino and the Interface Board into the Shortboard.
So I think some basic handicraft skills in electronics are necessary to fulfill the job, but then you will be rewarded with an inexpensive controller with lot's of functionality and nice stomp pushbuttons.