On Wed, Jun 28, 2023 at 1:19 PM Paul Koning via cctalk <cctalk@classiccmp.org> wrote: > > > > > On Jun 28, 2023, at 1:13 AM, Fred Cisin via cctalk <cctalk@classiccmp.org> > > wrote: > > > > DA, DC, DE connectors are a different size D shell than the DB, which is > > the one commonly used for a 25 pin cable. > > There is also DD, though I've never seen one in the wild. DA is the shell > for AUI connectors, DC is used for RS-422 (37 pins) I think.
The DD50 (standard density) has been used for SCSI-1 (maybe old Sun machines?) amongst other places. I've certainly used them. I did once fit an ST412 interface onto a DD50 socket. There's a total of 54 wires on the 34 pin control and 20 pin data cables of course but enough wires unused on the latter than you can get away with 50 pins. I've seen a DD78 on some HP device but I forget what. DC37 was used for RS449, PC external floppy drives,etc. DC62 was the connector for the IBM5161 expansion unit. There are DA26 and DB44 connectors but I don't think I've ever used them. FWIW I have seen Centronics parallel interfaces on DA15 connectors (there are enough pins for 8 data lines, strobe, busy, ground and a few other signals). There is NO standardisation, I've got a Tandata videotext terminal, a Philips videotext terminal and an HP2225P printer here and they don't even agree on the ground and data lines. -tony
