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,
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
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.
The 24-position type is used on HPIB, though I doubt there aren't other
applications. I've seen others as well, but nobody who's been around refers to
the 50-pin, 24-pin, or anything else other than the 36-pin version of this
particular connector series as a Centronics connector without risk of ridicule.
I think one U.S. manufacturer (Amphenol ???) made these under the "Blue Ribbon"
moniker, though I can't find any old enough connector catalogs to prove it.
more below ...
Dick
----- Original Message -----
From: "Tony Duell" <ard_at_p850ug1.demon.co.uk>
To: <classiccmp_at_classiccmp.org>
Sent: Wednesday, April 11, 2001 12:52 PM
Subject: Re: 50 pin SCSI to 50 pin centronics
> >
> > What's causing all the confusion here is the nomenclature. First of all,
> > there's only one Centronics connector I've ever seen and that's a
36-conductor
> > type. It was made for Centronics, which was at one time, a pretty good
printer
>
> Are you sure the 36 pin one was _made_ for Centronics? I've seen the 14,
> 24 and 50 pin ones on equipment a lot older than Centronics printers, and
> I wouldn't be suprised if the 36 pin one wasn't used somewhere else as
> well. Back then, it wasn't that common to have a custom connector made up
> if there was a standard part that would do the job.
>
> After all, 36 pins is not an ideal fit for the Centronics interface.
> IIRC, there are some unassigned pins. If they were going to have it
> custom-made, they could have had a 30 or 32 pin one made instead.
>
> > maker, though the Centronics line was pretty much killed off by the much
better
> > and less costly substitutes imported for the PC market some years before
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
didn't make a crimp-onto-ribbon-cable version until very late in the game, it
was not adopted as the standard. I do believe it's in the standard by now,
though, and that some firms other than SUN are using it.
>
> > it was, and still is, widely used in the telecom business. Not being a
telecom
> > type, I'm not aware of a generic name for that type of connector.
>
> Nor am I. HP called the 50 pin one a '50 pin Telco connector' at one
> point. But I've never heard that name used for any of the smaller ones.
>
> Over here the catalogues are split between 3 'generic' names for this
> series of connectors :
> 'Centronics' (after the most popular use for the 36 pin one)
> 'IEEE-488' (after the most popular use for the 24 pin one)
> 'Amphenol' (after the company that IIRC first made them, even though they
> make many other types of connector).
>
> I tend to buy them by stock number :-)
>
> > SCSI, however, in its various versions, uses connectors ranging from the
> > well-known and popular DB25 ( and a special smaller variant for APPLEs ) to
the
>
My mistake ... I was thinking about their FD connector, (?) or whatever it was,
some sort of almost-B-shell with only room for 19 pins.
>
> Well, the Mac+ used a normal DB25 for the SCSI port, just with a
> different pinout to that which some other companies used at about the
> same time...
>
> -tony
>
>
Received on Wed Apr 11 2001 - 18:37:08 BST