3 ms·

I vaguely remember there being some proprietary connectors that were the same as the standard with a single pin missing.

• dfox 1y ago
  IBM did that pretty often. And well, the original VGA connector had pin 9 missing and used as a key.
• dlcarrier 1y ago
  You might be thinking of VGA connectors, which were a DE-15 connector, similar to a DE-9 serial cable, but with an extra row of pins and often pin 9 missing.