Re: ParPort output low - hi-Z or ground?

> If you need opto inputs to the parallel port then you have a
> different configuration where the opto input is driven from the
> signal (limit switches, table sensors, etc) with an isolated

voltage

> source and the opto transistor is used to pull the parallel port

line

> low through a collector resistor.

Assuming a seperate external power supply and running the opto at 10-
15mA, the LED section of the opto will drive the parallel port side.

The parallel port side would either sink or source depending on which
way you have it connected.

So, assuming you are only referring to the 5 inputs, parallel port
pins 10,11,12, 13 and 15 see
http://www.doc.ic.ac.uk/~ih/doc/par/

I too would be interested in how you decide to connect them.

Dave