Re: multiple parallel ports through one connector?

Chris,

I wouldn't recommend "combining" grounds...

It was already done by IBM when they "converted" the centronics 36p
connector to the db25. This is partly why printer cables are so short
compared to serial cables. The loss of the individual signal grounds
reduces noise handling/rejecting cpabilities. So the reliability
over "long" distances is reduced. Certainly not something you want in
a cnc machine...

There are enough problems with the noise of "workshop" environment,
spindle motors, etc. that you shouldn't add to the possible problems,
IMO...

One more thing we REALLY miss from the old centronics standard is the
5V supply pin! Yep, right there on the connector for the optos, where
it "should" be...

Hope this helps.

Ballendo

--- In CAD_CAM_EDM_DRO@y..., CL <datac@l...> wrote:
> Carlos,
> Thanks for the private update on Indexer.
> I may as well comment on your quest here so others can contribute
too.
>
> You are not alone in thinking the 3 port connection is a little
hassle. But,
> really, if you try to "convert" 3 ports installed in their slots to
yet
> another type of connector, you still end up with the extra effort of
> soldering the same amount of Pins, and some "tangle" or mid box
behind the
> computer.
>
> Additionally, today a Parallel port is found pretty cheap. So I
would just
> buy them and use them. If you want to make a little cleaner
Install, do what
> I had done in the past. ALL of the necessary signals CAN be carried
in a
> single 25 wire printer cable for a 3 axis machine WITH the Jog as I
recall
> because you can combine all of the "Grounds".
<snip>