Re: [CAD_CAM_EDM_DRO] multiple parallel ports through one connector?

> Does anyone know if it is possible to take the PC's signals from
> three "parallel ports" and output them via one PCI card with a
> 50-pin SCSI or Centronics connector? Is such a thing available?
> I am trying to get IndexerLPT set up to talk to my controller box,
> and I'd like to find a cleaner way than using three separate
> parallel cables, and the associated breakout boards. Each port
> uses 14 pins plus ground. I know that 3 ports sounds excessive,
> but to drive 4 axes and use the joystick feature with the G-code
> frontend, I need 3 ports. The benefit is a lot of extra I/O.

I don't know any details of indexer LPT, but many motion programs
are unable to talk to PCI card 'parallel ports' as these work
in a very different manner from true parallel ports as found
on the motherboard or an ISA card.

There is an alternative to multiple parallel ports, and that is a
digital I/O board. These typically put something like 24 signals
(maybe more) into a single cable. Talking to them is easy, but
slightly different from talking to a parallel port, so it would have
to be specifically supported by the software. Therefore you should
probably contact ability systems with your question to see if they
provide (or would be willing to add) support for something like the
8255 digital I/O chip used on many boards. If you are not strongly
attached to indexer, any of the open source motion control packages
could easily be made to talk to such a board (provided that it is ISA
and not PCI).

One source of digital I/O boards is www.jdr.com

You can of course bundle the cables from three parallel ports
together, too.

Chris Stratton

-------------------------------------------------
Christopher C. Stratton
Engineer, Instrument Maker, and Horn Player
ccs@... 617 628 1062
http://web.mit.edu/~stratton/www/brassbuild.html