In theory, DB is 25 pin, DA is 15 pin. In practice anything "D sized" is called DB: DB9 (serial), DB15 (VGA, three rows), etc.
---- Original message ---- >Date: Wed, 2 Nov 2011 09:37:22 -0700 (PDT) >From: [email protected] (on behalf of Dan Kressin ><[email protected]>) >Subject: Re: [Discuss] OT: what is this cable for? >To: "Ricker, William" <[email protected]>,BLU Discuss <[email protected]> > >Ferrites, that's it! The ones on this cable actually appear very plastic and >light weight, and are not snap-on. > >In any case, I have to apologize for the unintentional misinformation. The >Centronics end is actually 36-pin, and I had a vivid "picture memory" of its >purpose this morning. It connected the printer to My First Computer, a Laser >128 (Apple IIe/IIc clone). Funny how memory works.. I can totally picture the >cable running through the old computer desk, etc.. > >So does anyone want to explain the difference between DB and DA? > > > > >>________________________________ >>From: "Ricker, William" <[email protected]> >>To: Dan Kressin <[email protected]>; BLU Discuss <[email protected]> >>Sent: Wednesday, November 2, 2011 11:23 AM >>Subject: RE: [Discuss] OT: what is this cable for? >> >>> Ribbon cable w/ two (the name escapes me ..) "ring things" to usually used >>>to fight inductance.. >> >>Snap-on Ferrite donuts actually *add* inductance, which rounds the corners of >>square wave digital signals, to prevent interference (both by and to) and/or >>induced spikes from lightning EMP. They come in a variety of specs which >>attenuate into progressively lower frequencies. Use the wrong one and you'll >>attenuate the desired signal too ! >> >>(One more pedantic than I might object that fighting interference is fighting >>*mutual* inductance, but that's not a measurable inductance outside of >>cross-talk range.) >> >>Yes the DA-15 was used as Game/MIDI port on early IBM PC ISA sound cards. But >>the normal MIDI adapter cable would have been DA-15 to pair DIN-5 (or XLR3). >>Since the game port was re-used to drive all sorts of things, that's a >>possible origin, as are any custom frobistats. The C-50 / CN-50 was abused as >>an easy expansion interface for lots of pre-miniaturization devices -- it was >>originally a family or range of telco analog connectors for twisted pair >>snakes, eg multi-line phones & PBX to punchblock cabling, that was adopted >>for printers, re-adopted for SCSI-1, because it was available relatively >>cheap due to volume of telco use. As the RJ series has been adopted more >>recently. The C-36 had obscure computer uses, not sure if larger sizes were >>ever digitally 'appropriated'. >> >>Bill @ $DayJob >> >> >_______________________________________________ >Discuss mailing list >[email protected] >http://lists.blu.org/mailman/listinfo/discuss _______________________________________________ Discuss mailing list [email protected] http://lists.blu.org/mailman/listinfo/discuss
