50 pin SCSI to 50 pin centronics

From: Don Maslin <donm_at_cts.com>
Date: Thu Apr 12 01:02:08 2001

On Wed, 11 Apr 2001, Richard Erlacher wrote:

> I had a Radio Shack Quick Printer II, which, IIRC, was a narrow, roll-fed
> electrostatic erosion printer that used aluminum-foil coated roll paper about 5"
> wide. I used it to label my parts cabinets. Being a repackaged Centronics
> printer, it had the usual 36-pin Centronics connector.

Just to muddy the waters a tad, do not forget that Xerox used a 50-pin
Ribbon connector on some version of the Diablo 630 (IIRC) in what they
called their (A)ll (P)urpose (I)nterface - API - which included
parallel, serial, and I forget what all else.

                                                 - don

 
> Centronics was using that 36-pin connector before Radio Shack ever contemplated
> getting into the compuer business. It was on the Printronix P100 we had on our
> Wang 2200 MVP back in '75. The very first time I ever saw a real parallel
> printer cable that didn't use the Centronics standard 36-position connector at
> both ends was on a PC, in 1981. Prior to that, the "toy" interface used by the
> Apple II was the only non-homemade one I saw in use on a commercial system.
> That was understandable in view of the package size constraints, however.
>
> Dick
> ----- Original Message -----
> From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
> To: <classiccmp_at_classiccmp.org>
> Sent: Wednesday, April 11, 2001 5:51 PM
> Subject: Re: 50 pin SCSI to 50 pin centronics
>
>
> > >
> > > The 50-position type was around for a long time, i.e. I remember them back
> in
> > > the early '70's and they weren't new then, in use with telecom gear. I've
> no
> > > idea whether the 36-position variety was made_for_Centronics, but it's the
> only
> > > connector that I've ever seen used on a genuine Centronics parallel
> interface,
> >
> > At the printer end, probably (although there were a _few_ pre-PC printers
> > that used a card edge or a header plug for a Centronics-like interface --
> > the Radio Shack Quick Printer 2 was one such IIRC).
> >
> > At the computer end, there were many connectors used. Some companies used
> > the 36 pin Blue Ribbon (I believe that _is_ the correct name). Others
> > used a header plug or a card edge, normally pinned out so that an IDC
> > ribbon cable with no twists could be used to link it to the 36 pin
> > connector at the printer end. Things like the 34 pin card edge on the old
> > TRS-80s, for example.
> >
> > > be it on a Centronics, Printronix, Okidata, (not the toys found attached to
> a
> > > PC, but the real "line-printers" ) or whatever sort of printer. The
> interface
> > > used on the PC parallel port does not precisely conform to the Centronics
> >
> > The PC printer port was designed to link to the 5152 printer which was a
> > badge Epson IIRC. That's why the interface is not _exactly_ Centronics.
> >
> > > standard, and was the first one I saw using a different connector. The
> point is
> > > that while the connector isn't exclusive to that interface, the interface is
> > > exclusively dedicated to that connector, to wit, it's still what's used on
> > > printers, even though everybody knows it's only going to be attached via a
> DB25
> > > at the computer end.
> >
> > Round here it might be _anything_ at the computer end :-)
> >
> > > there
> > > > > even existed any notion of a standard for SCSI. The old SCSI-1 uses a
> > > > > 50-position connector that looks like the Centronics type. Prior to
> SCSI
> > > fame,
> > > >
> > > > Sometimes. Sometimes (and this is in the standard IIRC), SCSI-1 used a
> > > > DD50 connector.
> > > >
> > > That's the one widely used by SUN. It's a better connector, but since they
> >
> > And others. The Ill-fated PERQ AGW3300 (aka PERQ3a) has a DD50 SCSI
> > connector on it.
> >
> > > didn't make a crimp-onto-ribbon-cable version until very late in the game,
> it
> >
> > For SCSI, I've neve seen anything bu the crimp-on IDC type. The pinout of
> > SCSI-1 using that connector was chosen so you could crimp a DD50 onto a
> > normal SCSI ribbon cable and get the right connections.
> >
> > Of course this doens't mean the connector didn't come out relatively late
> > -- I have no idea when the IDC version of the DD50 was first produced.
> >
> > -tony
> >
> >
>
>
Received on Thu Apr 12 2001 - 01:02:08 BST