> I have a CNC mill with a RS232 port. If I leave the cable connected to the > pendant, any spike in the workshop upsets the CNC control. Turing some things Weren't there RS232 opto-isolators around back in those days? Or what were they called exactly? Volker -- Volker Kuhlmann http://volker.top.geek.nz/ Please do not CC list postings to me.