Thx for inquiring...
Midi Solutions told me to connect MIDI OUT to MIDI IN and test if Send SX sends the SysEx data. It dumped data... and never stopped!
I was worried it might erase the SB-Live! soundcard's soundbank and so, I stopped it. Albeit I reported the result to MIDI Solutions, they didn't respond and I couldn't get any help. They don't have a programmer for it I wouldn't have a clue how to program the correct parameter with SysEx.
So, I might sell off this complicated Breath Controller at eBay and solder myself a simple stereo attenuator, based on the Morley foot-pedal circuit.
I wasted my money on "MIDI (no) Solutions"!
Besides, since you know a lot about MIDI...
I bought a cheap RollUp Piano with MIDI OUT, which works 6VDC.
I ripped the silicon/vinyl Kbd apart to trace the circuit and contacts. It has the usual 8x8 matrix circuit without visible diodes (i.e. they must be within the chip). I would like to connect an old 120-button accordion bass box onto it. Each button has only one contact.
There I would need to bundle lots of 3 to 4 note chords.
It would be far easier to wire one accordion button per piano key, and write a small MIDI filter program that converted the single notes to chords, assuming one doesn't exist somewhere already. To me, that's "simpler" than messing around with hundreds of wires and diodes, and you can change it any time. I googled for it, but couldn't find anything.
Would you know how, where to find it?
My latest idea/ tick is to "uniformate" the ordinary zebra piano layout!
Because its present irregularity (the sticking out, narrow black keys) is a pain in the proverbial; costing us years of scales and chords practice!!
I want to create a Kbd with very little key (contact) travel. That way the black keys can be almost level with the white ones, making it far easier for my "two left hands" dexterity to maintain the fingering distances. On my Synth Kbd the black keys are about 10mm above the whites, causing my fingers to run against them... while trying to judge the distances in a different scale. I haven't got the problem playing in C-major, because all keys of the scale are white (have no walls!).