50 pin SCSI to 50 pin centronics

From: Richard Erlacher <edick_at_idcomm.com>
Date: Wed Apr 11 18:46:38 2001

see below, plz.

Dick

----- Original Message -----
From: "Russ Blakeman" <rhblake_at_bigfoot.com>
To: <classiccmp_at_classiccmp.org>
Sent: Wednesday, April 11, 2001 2:16 PM
Subject: RE: 50 pin SCSI to 50 pin centronics


> The 50 pin with the hooks on the side is actually referred to as a
> Centronics 50 pin, or SCSI-I (external SCSI as well on older machines before
> SCSI-2 came along)
>
I've seen that too, but the folks making the reference don't know their butt
from a hot rock. Centronics never (at least as far as I have seen) used that
common 50-pin version that looks like the 36-pin version they had named after
their popular application. 20 years ago things were much clearer in this regard
because you didn't have idiots selling and advertising things they didn't
understand at all. Sadly, that's no longer the case.
>
> Most companies in the way back used either what was cheap or had specials
> made up just to keep you coming to them for cables, connectors, etc. Why
> does Apple had a different AUI port than anyone else? Why are there 9 pin
> and 25 pin RS-232's.....Why is Apple's on an 8pin mini-din?
>
In the "way back" an apple was something you had in your lunch sack, not on
your desktop. The evolution of the "Apple computer" coincides more or less with
the beginning of the end of intelligible conversation about such matters. The
justification for such things was probably cost and size, but "real" AUI still
lives on a DA-15 connector. Back in those days, RS232C spelled out the signal
levels and the signal names, and their functions, though quite inadequately, and
it wasn't the EIA that authorized the use of the DE9 for RS232-compatible
communcation, thoguh I don't know why, in view of the fact that only DB25-pins
2,3, and 7 were required to get the job done. Even today, lots of people talk
about RS232 when they're really talking about asynchronous serial communciation.
>
> > -----Original Message-----
> > From: owner-classiccmp_at_classiccmp.org
> > [mailto:owner-classiccmp_at_classiccmp.org]On Behalf Of Tony Duell
> > Sent: Wednesday, April 11, 2001 1:53 PM
> > To: classiccmp_at_classiccmp.org
> > 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.
> >
> > > 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
> >
> > 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 - 18:46:38 BST