Re: Help needed with Apple IIgs monitor

[mjmahon@aol.com (Michael J. Mahon)]

David Empson wrote:

>The letter after the "D"
>refers to the physical size of the connector.
>
>Assuming two rows of pins with the usual spacing and staggered
>arrangement, the common connectors defined by the relevant DIN standard
>are:
>
>DA15 (Mac/IIgs/IIc video connector, AUI port for Ethernet, PC joystick)
>DB25 (serial or parallel port, Mac/A2 SCSI port)
>DE9 (IIe/IIc/IIgs joystick, IIc/IIe/Mac mouse, PC serial port)
>
>There are also DC and DD prefixes, which are for larger connectors which
>I haven't come across in the realm of personal computers.  I forget the
>exact number of pins, but one of them is about 37 pins in two rows, and
>the other is about 50 pins in three rows (with the same pin spacing as
>the others, so the connector is taller).
>
>The 19 pin connector used for the floppy drive on the IIe/IIc/IIgs/Mac
>is one which falls outside the originally designated types, so it
>doesn't have an official second letter.  I use "D-19".

David, what you have written is absolutely correct (as usual!), but I
think that the nomenclature of "D" series connectors has now become
a matter of common usage rather than original intent.  Sometimes
the inventor loses control of the invention!

High-density D connectors are now universally tagged as "high density"
eliminating any possible confusion with the older variety.  And the older
D connectors are uniquely specified by the number of pins.  The result
is that the suffix after the "D" has become redundant and all such
connectors are now commonly denominated as "DBxx", after the most
common one, the DB25.

This is somewhat analogous to the use of the "Centronix" designation
for a 34-pin Blue Ribbon connector, or, by extension "x-pin Centronix"
for any Blue Ribbon connector at all!  (Particularly strange, since they
are Amphenol designs, and Centronix only popularized them on their
printers.)

I think it will be harder to change this than to get people to stop
calling all facial tissues Kleenex.  ;-)  And, since there is no chance
of confusion, why bother?  (Though the original "intended" nomenclature
of D-series connectors makes a great trivia question!  ;-)

-michael

 Email:  mjmahon@aol.com
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