Gentlemen, I have a Smiths Industries encoding altimeter, part # 01-200-103. And I have a ARC RT-859A transponder. I'd like to interface them in the Challenger I'm building. I've googled myself silly and can't find much of anything about how to hook them together. I've also checked the Essco site but they show nothing at all for Smiths instruments. Furthermore, the altimeter has a 26 pin male fitting on the back for which I need the matching female plug to go on my wiring harness. Can't find anything on that either. Does anyone have any idea at all where I should look or where I should start with this? Anything would be appreciated at this point. Thanks in advance!