Gregory's Serverthis basically means i'm buried in IBM schematics that use a totally weird representation of logic gates.
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 i want to build a breakout system to make it easier to test these cards. they use a 16-pin connector with 0.125" spacing between contacts. at the local electronics store, i could only find this 44-pin connector. the final product. you can barely see the glue seam. bonus points to anyone who knows why the connector pin alphabet is missing a few letters. further bonus points to anyone who knows why each contact has two wires connected to it.  @tubetime the obvious answer with the letters is they're gonna leave out the ones that can be confused with numbers. i'd imagine one of S or Z or both is left out as well. oh -- or they're the symmetric ones that don't tell you if you're reading it upside down :-)  @tubetime I and O too easy to confuse with 1 and 0? I feel like I've seen this before in e.g. Game Genie codes.  I != 1 Two wires? Because you wanted to be able to insert boards either way? But why?  @tubetime I have a front panel from some old electronic device that has the same letters removed  @tubetime I don’t see any traces on top of this card but my entry is: to get continuity on the top and bottom of the card at the same time. The leads go to teeth on one each of the top/bottom?  @tubetime For the same reason they're omitted in MIL connectors, I guess, ambiguity.  @tubetime     @tubetime Totally weird but unless I’m misinterpreting what I see there, capable of being printed on a line printer? @tubetime All the logic pages were printed on a line printer (1403 etc). There was a special character set for the job. |
this particular version of the 729 has a whole bank of SMS cards -- IBM's Standard Modular System which uses germanium transistors. these came out before their (equally odd) SLT cards and modules.