Prices to pay for old computers...

From: Russ/Alice Blakeman <>
Date: Sun May 24 20:43:00 1998

Tony Duell wrote:

> > > > Any time that you saw a piece of
> > > > equipment with a DB-25 connector on it, it was almost certainly a RS-232
> > > > connection.
> >
> > Not entirely true - in fact, probably a dangerous assumption! The D style
> > connectors date WAY back, when computers used tubes!
> Agreed. The maximum voltage for a D connector (at least a decent one) is
> something like 500V. A lot higher than most people expect.
> > > Main problem is that the Amphenol connector is too wide to properly fit
> > > on a standard IBM card bracket (yes, OK, they should have made the
> > > bracket wider...)
> >
> > Can you fit two DB connectors on a card bracket? That may be one reason
> > they moved the RS-232 to the DE style.
> Exactly. The serial/parallel adapter came out with the AT - and that was
> the first use of the DE-9 serial connector. And no, you couldn't fit 2
> DBs on a bracket. You can _just_ fit a DA and a DB on the same bracket -
> I've seen multifunction cards that do that. Problem is, the IBM case has
> a lip (so you don't scratch your hand on the board fixing screws) that's
> not in most clones. Getting the plugs into one of those cards on a real
> XT is interesting...

The older 500v capable D connectors had solid pins though of a heavier guage. Has
anyone noticed that many of them are lightweight guage and in some cases hollow?
This drops the voltage and current capacity way down. I just repinned the
connector on a VT 130 terminal for a local business and noticed the difference in
the old pins and the new ones. You bend a new one and it breaks, and old one can
sometimes be straightened unless it's kinked (and then cracks).

 Russ Blakeman
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Received on Sun May 24 1998 - 20:43:00 BST

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