OT: <was springfield> <is data transfer via parallel port off old systems>

[Roy J. Tellason]

On Wednesday 02 August 2006 05:44 pm, Don Y wrote:
> Roy J. Tellason wrote:
> > On Wednesday 02 August 2006 05:02 pm, Don Y wrote:
> >> I have an *8* headed "laplink" (lowercase L) cable but, IIRC,
> >> they are just various combinations of connectors/genders and
> >> pinouts (but still a serial cable).
> >
> > That's a bit much.
> >
> > I have a couple of 9-to-25 pin size adapters that I need to check the
> > connections on,  and am not sure I have them in both genders.  And some
> > connector shells that'll take a 25-pin connector at each end,  which I
> > got seeing them as being handy to make adapters with.  But the need for
> > such stuff never arrived,  so I never got around to building them, 
> > except for a couple of gender changers.  If I ever do it'll be easy
> > enough to have one test cable that's wired straight through and then make
> > up any adapters I might need.
>
> I have a box of 25 pin M-F DB25 cables wired 1<->1.

I could probably use some more than the couple I have,  but there's been no 
real need lately.

> And, a small box of "widgets" -- little 2x2" clamshells
> with a pair of DB25's on each end.  Sex varies -- some are
> M-M, some F-F, some M-F.

Just the things I was referring to.

> I wire each of these widgets for a specific purpose:
> - gender changers (M->F, F->M)
> - "null modem", "null terminal"  :-/
> - PLIP
> - Sun "port A/port B" swap
> - device specific requirements (some devices use unusual
>    pins for handshaking, etc.)
> - etc.

If you have that info in a file I sure wouldn't mind taking a look at it.  
Could come in handy some time.  I know I've run across the odd bit now and 
then.

Like the DEC printer that was the exact same mechanism as several others I'd 
seen around that time (Apple imagewriter?  Some others I can't recall) but 
which required one of the handshake lines to be pin 10,  or maybe it was 11.  
Nothing special about that printer,  and it was really pretty slow compared 
to a lot of others out there (though not as noisy either),  with one 
exception -- when you fed it a "*" it printed an actual 5-pointed star.  Only 
printer I've ever seen that did that.  :-)

> This greatly cuts down on the typical "tangled box of assorted cables" you
> find in most places.  And, the hassles involved in trying to find THE right
> cable for the job.

Yeah,  I can see where it would.  And this is exactly the sort of thing I had 
in mind when I wrote that.

> Instead, I dynamically fabricate the cable that I need by patching lengths
> of straight through M-F cables together.  Then, apply whatever combination
> of "widgets" are needed on each end (in theory, you only need to do this on
> one end but sometimes you need a 25->9 pin adapter and other times its
> easier to do some of the "widgeting" on each end instead of having 2 or
> three cascaded widgets hanging off one end of the cable)

Just so.  Those things stretching out horizontally behind an item of equipment 
sometimes doesn't work real well either,  so a short cable at that end to let 
'em hang might be another option.

> The only downside is making the widgets -- since they are so compact,
> getting 25 conductors in the clamshells is a bit challenging (unless you
> resort to really fine wire).

I did make a couple of gender changers that way,  and it didn't seem too bad.  
Though that was a bunch of years ago and my eyes aren't what they used to be.  
The shells I have are two separate plastic bits,  so I can leave them out of 
the way until fairly late in the process.

Is there a standard about which parts of that stuff are supposed to get the 
screws and which are supposed to get the little threaded posts and such?  I 
bumped into hassles with that already,  too.

-- 
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin