wheres the noise

i have got some strip b with a udn2982 on there to step up the 5 volt step and dir signals to 24volt for the servo drive i have im having a problem of stray voltage on the parra port side of the chip and thus on the drive side also if i take off the para port cable then no voltage and no output

is there usaually stray voltage on the para port without a brakeout board ? what would be a subible resistor to kill it when i can get the interface right then ill be ordering my mesa hardware will that be the same ? or will that solve it anyway ?

Not clear what you mean by stray voltage.
The parallel port pins are TTL compatible
(minimum 2.4V out for a high and maximum 0.4V out for a low)

The pin states may be unpredictable until linuxCNC has control of them however so they are not suitable for use for things like drive or spindle enables without additional logic (like a charge pump)

What voltages do you read from the parallel port output pins in the high and low states? (you should be able to unlink them from the driving net in HAL and setp them 'true' or 'false' to check )

Thanks pcw you made me relook thing just as I was leaving the shop

I was having a constant 2.2 volt (me thinking the para port was 5volt)

So I changed to pin 3 and I thought I had changed the config to match but thinking harder about this I may have even been in the dir pin (was only jogging one way) this was high all the time so having changed pin I have had some steps out of the drive

Progress is afoot

One more thing what value would you recommend for a pull down pcw ?

The steps I had was only every so often not a constant move so the output of the chip is staying high for awhile maybe ?