18 Aug
2006
18 Aug
'06
3:18 p.m.
On Friday 18 August 2006 04:19 pm, der Mouse wrote:
37 pins, and it's found on the metal bracket of original PC/XT floppy
controller cards.
> BTW the B
in DB refers to the size shell. The 25 pin connectors
> used on the original IBM are B size. Other sizes use a different
> letter ie DE, etc. But a lot of people call every size "DB"
Until relatively recently I was one of them. :-(
So what letters are used for other sizes?
DA is the 15-pin size, the one used by AUI Ethernet back in the heyday
of 10base5.
DB is the 25-pin size, the one that's standard for serial ports
(de-jure standard, not the 9-pin de-facto standard). Also used for
peecee parallel ports and older Macintosh SCSI, and doubtless a bunch
of other things too.
DC is a size I almost never see, and I don't remember the exact pin
count. 37? 39? Something like that. DD is a much larger size, supporting 50 pins. Some of
the older Sun
equipment uses this for SCSI, which is the only use I know it from.
I did run across those on the boards I was recently wondering about in here.
They're the only ones I know of (excepting "VGA" sockets) that use three
rows
of pins.
DE is the small size, used with 9 pins for the serial
connectors I
mentioned above and with 15 pins for peecee video ("VGA").
I don't know why the order makes so much sense for DA through DD and
then goes wonky for DE. I conjecture that when it was originally
planned, nobody expected it to be used for anything that small, so the
DE was tacked on as an afterthought. (I suppose they could have used
D@, but that would make sense only to geeks who know their ASCII. :)
Works for me. :-)
I also don't know whether there are any other
sizes with names. Other
sizes, though rare, do exist; for example, NeXT used a D-shell
connector of an odd size, with something like 19 pins, to drive their
greyscale video displays.
It's also my understanding that the Atari ST (?) used an oddball of that sort,
maybe 23 pins?
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin