On Thursday 02 February 2006 08:48 am, Richard wrote: Oh, yes, the 44 pin cards. There were quite a few connectors that used the .156 spacing for contacts (before everyone went to .1 centers). They still are around in lots of places. The "numbering" of the contacts was USUALLY one side with numbers, and the other side with letters (missing G, I, O, Q). This means that the 44 pin connector had letters from A to Z! I designed a 6800 system using these cards (the prototyping cards were available where I worked at VERY low cost!), and it worked quite well. 8 data lines, 16 address lines, and 7 controls. I used 21 & Y for +5 volts and 22 & Z for ground. Look, it was 1975, and only 1MHz!. It actually worked out quite well, and I get a company going for around 4 years (it died of bad management!). Yes, there were LOTS of prototyping boards around for this from factor, and I was thankful for that. One of the goodies that I did was a Centronics interface using only a single 6821 (PIA) on the board. It worked quite well (a slot select line was wired into the board which made it pretty simple!). Those were the days. Simple interfaces and all the source you could see. (*SIGH*) Yes, STD bus is 56 pins at .150 spacing, but same form factor! __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com