50 pin SCSI to 50 pin centronics

From: Iggy Drougge <optimus_at_canit.se>
Date: Fri Apr 13 08:49:17 2001

On Thu, 12 Apr 2001, Tony Duell wrote:

> > > 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 suppose that might be the case, but I don't really think the
Commodore/Amiga engineers were stupid enough to place those outputs at
volatile positions.
According to HWB, they're at pins 11 and 18.

> 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.

What about those two-in-one DB 25 serial ports seen on SUNs and big-name
PCs?

> > > 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).

It's bad enough that there aren't any "shoes" for the cables, but the
density gives it a striking resemblance to a jungle.
Received on Fri Apr 13 2001 - 08:49:17 BST