5 Sep
2007
5 Sep
'07
11:18 p.m.
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), DD=50 (three rows), DE=9. The DE shell is also used
DC37, actually
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
In the high-density range, the standard sizes seem to be (in increasing
shell size) :
DE15
DA26
DB44
DC62
DD78
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
The common uses (on various machines) are :
DE9 : MDA, CGA monitors, PC/AT serial ports, some DEC printer (serial)
ports, Commodore/Atari Joysticks
DA15 : PC joystick, BBC micro analogue port (joystick :-)), AUI ethernet
DB25 : Real RS232 ports, PC parallel ports, Mac SCSI port, IEC625
interface (IEEE-488 on a DB25 connector!)
DC37 : PC external floppy interface. Some QIC tape interfaces. Canon 'VDO'
direct laser printer engine interface.
DD50 : Sun (and PERQ 3A) SCSI interface
DE15 : PC VGA (and higher) video
DA26 : Not seen it
DB44 : Not seen that either
DC62 : PC expansion unit
DD78 : Some HP multple seiral ports
Of course all these connectors were used for many other things besides
(my ACW has a DB25 keyboard socket, a DB25 user port and a DC37 '1MHz
bus'. I've wired all my HP 8-bit parallel interfaces for the 98x0 and
9815 to DC37 sockets, and so on). and they're used on things other than
computers.
[...]
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. :)
I bleieve that's correct. Also '@' is 'letter 0' only in ascii :-)
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.
I've heard them called the 'DF19' and 'DG23' (Amiga video connector?)
but
I don't know how official that is. Probsbly not at all!
I've heard that HP used 3 pin and 5 pin D-shaped seiral connectors on
some of their older machines. Were these DE-size shells or something else?
-tony