D-shell sizes [was Re: Slightly rare Mac 512k with D(?) -25 connector]
Roy J. Tellason
rtellason at verizon.net
Thu Sep 6 00:13:20 CDT 2007
On Wednesday 05 September 2007 11:47, der Mouse wrote:
> > [...] a 25-pin D connector reminscent of the Mac "SCSI" connectors on
> > Mac Plus and other machines. [...]
> > Forgotten what the correct designation for those D-connectors is, and
> > wanted to get this out fast in case anyone wants it.
> The 25-pin size - the one used for the MAC SCSI you refer to, the one
> called for by the mechanical portion of the RS-232 spec, the one used
> for peecee parallel ports - is DB.
> Using pin count for that same pin spacing, the table is DA=15, DB=25,
> DC=39 (I think),
I'm thinking 37...
> DD=50 (three rows), DE=9. The DE shell is also used
> in a 15-pin variant ("VGA"), but the pins are spaced substantially
> closer than in the DE-9. DA is probably best known for peecee joystick
> connectors, but it also got used for AUI Ethernet back in the 10base5
> days, before even 10base2, much less 10baseT. DC doesn't get used much
> in my experience; I think I have a few SBus cards that use it for the
> fat end of their octopus cables.
Didn't the original peecee's floppy adapter card have one of those on the
metal bracket to connect external floppy drives with? I had an external IBM
floppy drive a while back, pulled the drive out of the box to use for
something, and now I have this box with a little bitty switching power
supply in it and a short cable with one of those connectors on the end of
> DD was used by Sun for SCSI back in the Sun-2 and Sun-3 era, and also got
> used for IPI disks. DE is probably best known for peecee serial ports
> and "VGA" video (a lot of people don't realize the shell size is the same
> for those two), but I've seen it used for other things, such as Sun-3
> monochrome video. I'm sure each size has plenty of other uses I know nothing
> about, too.
Joystick ports on lots and lots of things, the c64, vic-20, Yamaha CX5,
Atari 2600 (?) game consoles, etc.
> I don't know why they are out of order. I speculate that someone
> designed DA through DD, never expecting D-shell to get used for
> anything under 15 pins, then had to tack on the 9-pin size later.
> (Arguably they should have called it D@, but that would probably have
> been too geeky. :)
> There exist D-shell connectors of other sizes, like the NeXT "black"
> hardware video connector (which held something like 19 pins). I don't
> know whether they have names in the DA..DE series; I suspect they have
> no standard names because they're not standard sizes.
Didn't the Atari ST machines use something odd of the sort? I'm thinking it
had 23 pins but I've never actually seen one of those or worked with one.
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