Thanks for that link Zonk.
Based on the info at the Resmed site.
30 days of detailed data (graphs)* on the SD card - so what do you guys do if you wish to hold more than 30 days worth of graphs etc if  using SleepyHead or  using Rescan?
I'm presuming the solution is simple but ----- I'm not sure.
SD card saves most recent 30 days of detailed data and 7 days of waveform graphs
So it helps to download at least once a week and have the card inserted in the machine otherwise detailed is lost as detailed data written directly on the card and not saved by the machine
When you import/download data to Sleepy Head/ResScan the data is saved on your computer.