Jim,
Yes
Rather than repeat what already has been posted I would suggest you take a look at the thread
"Problems Threading On The Lathe". You need an index input in order to have the G32 cycle work.
In the last few pages of that thread you will find explainations of how the threading cycle works. Take a look at some of my recent postings on what tests i have done and how they were done. That includes both the threading cycle and testing of the lathe and computer.
RICH