On collecting printers...

Tom Watson tsw-cc at johana.com
Sun Jan 27 16:29:14 CST 2008


On a previous message, dwight elvey <dkelvey at hotmail.com> said:

> Hi
>  Does anyone know which Centronix ( sp?) printer the 36 pin connector
> for parallel printers became standard?
> Dwight

It seems that they started using it in the mid 70's.  The connector was an
Amphenol 36 pin "micro-ribbon" type, one of the various sizes available.  As a
point of reference IEEE-488 (HPIB) standardized on a 24 pin version of the
connector, and the phone company (It was called the Bell System in those days)
used a 50 pin version for their cabling of telephones (25 pair cables as well).
 The connectors were pretty common, and worked VERY well, as the wiping
contacts were ultra reliable.  In the lab where I was working at the time had
standardized on the 50 pin version for connecting things together (this was in
the mid 60's).  So, the connector has been around for quite a while.

Of course, I could comment on their choice of pinouts, being as how they
switched the ground return from one side of the connector to the other about
1/2 way down (what were they thinking!).  The problem is that this is now
standard, and nobody wants to change it.  (*SIGH*).

In that era of computing (electronics) many connector styles were used.  Some
stayed on, and others died.  The "D-sub" is another style (DA-15, DB-25, DC-37,
DD-50 (three row!), and DE-9).  People fail to understand that the "D" is the
connector style, and the letter following (A-E) is the size of the connector. 
When IBM went to the DE-15 connector for VGA, they might have shown some
people, but it still amazes me that the 9-pin connector (properly called a
DE-9) is referred to by an incorrect name (not mentioned here!).

-- 
Sorry,
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