Jim Weir wrote:

They didn't by some wild chance include a schematic with it, did they?

No, sorry. Really what it turned out to be was rewiring the
helmet. I replaced the earphones (just the...uh...'speaker'
part, not the heavy plastic cups) and bought microphone.
I also got a prewired harness to hook it all together.
I probably could've gutted a headset and gotten the same
stuff, but a) it was cheaper than a decent headset, and
b) the mic has a bayonet mount that plugs into an oxygen
mask receiver - I'd've had to get that anyway.
I've still got the old parts if I ever need to convert it
back, but that's not likely.

Dave 'up chit' Hyde