I've been reading a lot about this macro, and I am really confused, was hoping someone can shed some light on this topic.... What exactly is the purpose of using a macro for a tool change? In all my yrs of cnc machining, I have never run across this. A simple T command with an M06 is all I ever needed to change tools. The ATC on this Funuc O-M will not work. There is a 9020 macro program in the memory. Do I need to call it up as a subprogram in order to change tools? That just doesn't make sense to me to use a separate program for a tool change... Can someone post an example of how the progrom should look to change tools? Any help is appreciated.