D-shell sizes [was Re: Slightly rare Mac 512k with D(?)-25 connector]

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 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. 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. 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. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B