*** Rests ***
For rests, use the G04 dwell code along with the P code to specify a dwell time in seconds. A 0.25 second rest is represented in this example:
G04 P.25
Note: I found that Mach 2 doesn't go in and out of dwell fast enough, so I had to use P.0625 instead of P.25 for the rests in the Star Wars Imperial March. It still wasn't short enough in my opinion, but I think there might be a minimum dwell time you can do since lowering it more doesn't seam to do much.