6 Oct
2007
6 Oct
'07
11:42 a.m.
Date: Sat, 6 Oct 2007 03:42:34 -0400> From:
rtellason at verizon.net> To: cctalk at classiccmp.org> Subject: Re: Setting up a
VAXstation> > On Friday 05 October 2007 18:42, Tony Duell wrote:> > > >
I'm not so sure about that. Very often in setting up a vintage computer> > >
> you'll need a special cable (RS232 serial cables being an obvious> > >
> example, there are all sorts of odd pin-swaps you need for some> > > >
machines...), and it makes a lot of sense to be abe to make it up. You> > > >
can't always buy the right cable off-the-shelf, particularly not for> > >
> obscure classics.> > >> > > I'd *still* like to someday get my
hands on one of the fancier breakout> > > boxes I used to see in catalogs...
:-)> >> > How fancy is fancy?> > Not too terribly, considering I
can't in any way justify spending much if any > money on such a thing. The ability
to interrupt any of the pins, maybe do > cross-connecting, and LED indicators would be
nice.>
If you can't find one of these at someplace, you can always
make one. LED's that are rated for 20ma will still give out
noticable light at as low as 1 ma. Just design them for
about 2 ma at 5 volts and they should work fine over the
full range of RS232. Resistor limiting values of about 1500 ohms
should be fine.
Using two screw terminal blocks is a lot easier than locating
28 ga. wire for jumpers. Just put it on some vector board.
Even a piece of plywood and some hot glue would be fine.
Nothing hi tech about it.
If you really wanted to be fancy, you could add two 9V
batteries to drive static values for some of those hard to
figure out control line problems. You just need to add
some current limiting resistors to these.
Dwight
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