I own a remstar mseries CPAP machine and here is how to get into the menu where you can change the settings:

1. Unplug the CPAP power supply.
2. Open the top plastic flip cover
3. Hold down BOTH arrow buttons
4. Plug the AC power back in while continuing to hold down the arrow buttons
5. Release the arrow buttons after you hear two quick beeps

Now you can get into the setup menu by pressing the + button. You will see:

1. Therapy Mode (not adjustable on my machine)
2. CPAP Pressure (This is the normal Pressure-put in what your doctor has prescribed for you)
3. Altitude (1, 2, or 3-I believe 2 and 3 are for higher altitudes; I just leave mine at 1 since I’m at sea level)
4. Fine Pressure Adjustment (I haven’t ever changed this)
5. Ramp Time (This is great for fine tuning how long you want the Ramp time to be. I started out with the longest ramp time of 45 minutes and now after CPAPing for a while I’m down to 30 minutes. You shouldn’t have to go to the doctor to adjust this!)
6. Ramp Start Pressure (My prescription is 7.0 cmH20 and I have my Ramp Start Pressure at 6.0. If you’re just starting out it may be easier to use a lower Pressure initially, maybe even the lowest setting then work your way higher if needed.)
7. Mask Alert (This will send out some beeps if your mask comes during the night. I leave mine OFF since sometimes it’s hard for me to get back to sleep after waking up in the middle of the night.)
8. Auto OFF (This doesn’t work as well as I want since it takes maybe 30 to 60 seconds for the machine to turn off, and it’s really loud. I usually reach over and just turn it off myself even though I have this feature on.)
9. Patient Reminder (I don’t use this feature)

You can adjust the C-Flex feature without unlocking it, but it is also available in this unlocked menu.