[rescue] cheap external scsi cables?

r.stricklin bear at typewritten.org
Tue Oct 11 19:49:53 CDT 2005

On Oct 11, 2005, at 4:33 PM, Bill Bradford wrote:

> On Tue, Oct 11, 2005 at 04:52:05PM -0600, Arthur Wouk wrote:
>> i think these are called DB50s.
> I've always heard of and referred to them as "HD50"s.

Not to  bring over a perennial flamewar from another list I'm on, but  
it's a "DD50".

The first "D" refers to the general series of "D-sub" shells. The  
second "D" refers to the size of the shell. The number refers to the  
number of conductors (maximum, traditionally).

DA = 15 conductor: PC Joystick, Ethernet AUI
DB = 25 conductor: old-school PC serial port, parallel port,  
Macintosh SCSI
DC = 37 conductor: old-school PC external floppy
DD = 50 conductor: old-school Sun SCSI
DE = 9 conductor: new-school PC serial port, TTL video (MDA, CGA, EGA)
DF = 19 conductor: NeXT video, Macintosh external floppy
DG = 23 conductor: Amiga video, Amiga floppy

High-density versions can include the DA26, the DB44, the DC62, the  
DD78, and the DE15. I've also seen DD100 connectors on some IBM  
communications equipment, like the 8-port RS-232 Microchannel ARTIC  
PortMaster Adapter/A.

The conductor number can be annotated in several ways, most  
recognizably with a "W" to indicate how many of the conductors are  
coaxial. For example, the DA3W3 that was used as a color framebuffer  
connector on IBM, Apollo, and DEC workstations. Or the DB13W3 that  
Sun popularized. Or even the DC7W7 that was on my old Miranda  
DigiLinx ISA SDI 4:2:2 video I/O card.

Also, the normal VGA connector is, most correctly, a DE15.


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