I had the Respironics Remstar M series model 510, which was supposed to be the newest Autopap out. I hated the noise and got me DME to exchange it for the ResMed AutoSet II w/EPR. It is as silent as a mouse and no big blue lights! I can't tell you about the ResMed cpap models exactly, but mine is in CPAP mode, not Auto mode and I have pushed the on button multiple times because I couldn't tell for sure it was working! This one's a keeper.
ResMed Auto Set II w/hi4 Pressure 9 - 20 EPR at 3 Mirage Softgel or , FitLlife
Orig AHI 30.4 RDI 36 & RLS/PLMB