Cycle Computer Corporation Sun clone board...

Scott Stevens chenmel at earthlink.net
Fri May 27 21:05:32 CDT 2005


On Fri, 27 May 2005 01:52:54 +0100 (BST)
ard at p850ug1.demon.co.uk (Tony Duell) wrote:

> > On the parallel port side of things, I suppose it might have toasted
> > something. No great loss there though. Grr to Cycle for not
> > providing labels to stick over the back of the case to warn that
> > what's labelled as a serial port actually isn't on their boards! (I
> > suppose this is one time where the PC standard of using male sockets
> > for serial ports would have made things obvious too)
> 
> The _correct_ standard is to use a male DB25 for a DTE (terminal) and
> a female one for a DCE (modem). The old way to rememebr that (and I am
> 
> showing my age now) is that Ma Bell is female, and that's where you 
> rented the modem from. The practical reason was you bought the
> terminal but rented the modem, so any bent pins were on the bit you
> owned and were thus not free repairs :-)
> 
> You can moan at IBM for using a DB25 for the parallel port rather than
> a 36 pin Blue Ribbon connector....
> 

Yes, but a 36 pin connector never would have fit on the 'olde standard'
for the IBM-PC, which was an MDA card with a 9 pin connector for video,
and a 25 pin connector for the printer.  Many, many first-generation PCs
never had any 'I/O' beyond this (except the 37 pin connector on back of
the floppy controller for the external third and fourth floppy drives,
of course, which nobody ever used).  Moving data around was a sneakernet
thing.  Or you printed it on paper.



> -tony


More information about the cctalk mailing list