What this really says is that in order to connect two devices, you have to know
precisely what you're doing. That's hard, nowadays, when the mfg's documents
are printed in large type on a business card. Things have gone downhill.
Manufacturers don't provide documentation because nobody reads it.
Dick
----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
To: <classiccmp_at_classiccmp.org>
Sent: Thursday, April 12, 2001 12:50 PM
Subject: Re: 50 pin SCSI to 50 pin centronics
> > > IIRC, the RS232 standard specifies a 25 pin connector. So strictly there
> > > are no 9 pin RS232 ports. If you mean why do PC/AT machines have a DE9P
> > > for the serial port, it was because (a) 9 pins is enough for the active
> > > signals on said port and (b) you can fit a DE and a DB on a single PC
> > > bracket, so you could have a combined parallel/serial adapter card. Which
> > > IBM introduced with the PC/AT IIRC.
> >
> > Oh, but then you lose a lot of fun. The Amiga DB25 serial port features
> > among others audio output on some pins. =)
>
> So presumably using an all-pins-wired cable to link it to some true RS232
> device that happens to implement all the pins is a good way to let magic
> smoke out...
>
> I've actually seen a device that has a single DB25 with the stnadard set
> of RS232 signals on the stnadard pins (1-8 and 20 I think), and a
> TTL-level Centronics-like parallel port on the other pins. Now that is a
> device that you certainly don't connect to just any RS232 port.
>
> >
> > > And Apple used the 8 pin mini-DIN on the Mac+ and later because there
> > > wasn't room for the DE9 connector used on the earler Macs. Hardware
> > > hackers have been complaining ever since -- those mini-DINs are about the
> > > worst connectors in the world to wire!
> >
> > Try a DIN-13 for size.
>
> I have done (and a DIN14, which is actually easier to wire than the
> DIN13). I still think the mini DIN 9 is the worst to do (it was used on the
> mouse port of the Archimedes, for instance), and the mini DIN 8 is only
> slightly better than the 9 (and a lot worse than the DIN 13 and DIN 14).
>
> -tony
>
>
Received on Thu Apr 12 2001 - 19:28:14 BST