What is this external cct? Sometimes acronyms are not understood by everyone. If you wish to use the parallel port as a poor man's digital I/O port you should be aware that you cannot control individual bits. You must update a port (8 bits) with a new value. Examples ship with LabVIEW on how to do this. You can search the Example Finder (Help->Find Examples and search for "parallel"). Also, do a search on these boards and you'll find plenty of examples.
