Instead,
IBM used the
female one for the parallel printer connection!!
Using a DB25 of either gender for a parallel printer connector was
brain-damaged.
Why? I have many things here that use DB25 conenctors for other than
RS232 interfaces, so I don't see the problem with using it for a parallel
printer port.
My complaint about the IBM PC in this context is that none of the
conenctors are labelled. Yes, the connector plates do look differnet if
you know what to look for, so you can tell MDa from CGA from EGA monitor
sockets (all DE9 sockets), but most users woulnd't know waht to look for.
They should have been labelled..
The really brain-dead use of DB25s on a machine of that period is the
HP150. That thing has a couple of DTE RS232 ports on DB25 _socket_. Yes,
the wrong gender. That's bad enough, but there's an optional
parallel+HPIL (not HP-HIL, I do know the differnce) board for that
machine. The parallel port is on a DB25 _plug_, I guess to make sure you
can't plug an HP serial cable in by accident. And would you believe the
pins are a mirror image of the IBM parallel port. In other words, if
they'd fitted a socket to the board, the IBM printer cable would plug
straight in and work... I would bet they originally intended that and
changed the conenctor gender at the last minute to prvvent lusers
plugging serial cables into parallel ports or vice versa
-tony
