Re: Alternative IO cards

["Peter L. Ashford" <ashford-at-SDSC.EDU>]

Hi,

I'm fairly new to this list, so I don't understand everything that goes
past, but I'm learning.  On the other hand, I understand computer
technology quite well.

ISA is dying fast.  New motherboards supporting ISA are getting harder and
harder to find.

Parallel ports are dying slowly.  They will probably be available on
motherboards for the next 5 years or so.

What's left?  Custom boards, USB interfaces and Network interfaces.
Custom boards tend to be expensive, by their very nature.  USB interfaces
tend to have latency issues (protocol not designed with 'real-time'
applications in mind).  Network interfaces may be what is needed.

Has anyone tried any of the network devices for sharing parallel printers?
These are available with 1-3 parallel ports, from HP and Intel, among
others.  They are fairly inexpensive (about $100-$250), quite small, and
VERY reliable.  You plug in a 10Base-T network, power, and the parallel
device.  What I don't know is if they will work with stepper motor
controllers.  I do know that some of them have speed settings for the
parallel ports, so that they don't outrun the printer.  This would be
quite helpful for CNC controllers.  Will it work?

The other thing that is needed is a 'parallel protector' that protects the
parallel interface from shorts, overvoltage and undervoltage, in the
controlled device.  Under normal conditions, it wouldn't do much, but
controller boards fail, and we don't need a voltage spike taking out
hard-to-find (in a few years) parallel interfaces.  Has anyone seen or
tried this?

				Peter Ashford