2 Feb
2025
2 Feb
'25
9:57 a.m.
On 02/02/2025 07:29, Tony Duell via cctalk wrote:
On Sat, Feb 1, 2025 at 10:54 PM Fred Cisin via cctalk
<cctalk(a)classiccmp.org> wrote:
> IBM used a DB25 socket for their printer port at the computer end,
> (male on the card for serial, female on the card for parallel
"Centronics")
> THAT, of course caused some idiots to attempt to use the parallel port for
> serial and vice versa. "I just need a 'gender changer'!" :-)
Once saw an IBM Quietwriter damaged by that very action. It was not
happy with 12v on its Centronics port..
The worst screw-up there (IMHO) came from HP in the
HP150 series. This
machine had 2 RS232 serial ports as standard on DB25 sockets, wired
for some inexplicable reason as DTEs. There was an add-on board that
included a parallel printer port. To avoid confusion, this was a DB25
plug. But the board had been laid out for a DB25 socket using the IBM
PC pinout. The result was that stb/ ended up on pin 13, D0 on pin 12,
and so on.
-tony
Dave
G4UGM