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.
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 Wed Apr 11 2001 - 19:16:37 BST