How to Download CPAP Data from Your SD Card (ResMed, Philips, Löwenstein)

Your CPAP machine quietly records far more than the cheerful "hours used" number that shows up in the manufacturer app. The detailed therapy data — your apnea events, leak rate, pressure, and even breath-by-breath flow — lives on the SD card tucked inside the device. Getting that card out, reading it, and understanding what's on it is the first step to actually seeing how your therapy is going. This guide walks through the process for the three brands SomniCharts supports — ResMed, Philips Respironics, and Löwenstein — and points you to where you can read the files without installing desktop software.

This is part of our CPAP Machines & Devices hub. If you've ever wondered why the polished app on your phone feels thin, that's because it is: the full picture is on the card.

Finding your SD card slot (by brand)

Every modern CPAP records to a removable SD card, but manufacturers hide the slot in different places. Here's where to look.

ResMed (AirSense, AirCurve)

ResMed is the most common brand in the U.S., and the slot location depends on your model:

• AirSense 11 — the SD card slot is on the side of the machine, behind a small flap. (More detail in our AirSense 11 SD card guide.)
• AirSense 10 — the slot is on the back of the machine, near the power and humidifier connections. (See the AirSense 10 data guide.)
• AirCurve 10 and 11 (BiPAP/ASV bilevel models) — these mirror their AirSense siblings, with the card on the back (10) or side (11). Bilevel machines record additional pressure channels; our AirCurve bilevel data guide covers what's unique.

Philips Respironics (DreamStation 1 & 2)

On both the DreamStation 1 and DreamStation 2, the SD card slot is on the side of the device. On the DreamStation 1 you'll usually find a card pre-installed under a small door; on the DreamStation 2 the slot is similarly accessible from the side. (One major catch with the DS2 — covered below — is that the data is encrypted.)

Löwenstein (prisma series)

Löwenstein's prisma machines (prisma SMART, prisma 20A, prisma 30ST, and others) use an SD card along with other data interfaces. The card slot is typically on the side or rear of the unit, depending on the model. Löwenstein is an under-served brand when it comes to consumer software, which is exactly why being able to read its card matters — our Löwenstein prisma data guide goes deeper.

Tip: If you can't locate the slot, check your machine's manual or look for a small rubberized flap. Never force a card door open — they're spring-loaded or hinged, not glued.

Safely removing and reading the card

The data on the card is being written every night, so a little care prevents corruption.

1. Power down or pause therapy first. Make sure the machine isn't mid-write. The safest moment is when it's off and not actively recording.
2. Push to release. Most CPAP SD slots are "push-push" — press the card in gently and it pops out. Don't pull it out by force.
3. Insert it into a card reader. You'll need: - A laptop with a built-in full-size SD slot, or - A USB SD card reader (a few dollars online), or - A microSD-to-SD adapter if your machine uses a microSD card (some do).
4. Open the card like any USB drive. It will mount as a removable drive on Windows, macOS, Chromebook, or Linux. You'll see folders — don't rename, move, or delete anything if you ever plan to put the card back.
5. Copy the whole card. The simplest, safest approach is to copy the entire contents to a folder on your computer (or straight into an upload). That way you don't have to guess which subfolder holds the data.
6. Re-insert the card afterward. Your machine needs the card back to keep logging. Putting it back in the same machine is fine; the device picks up where it left off.

If your machine offers a manufacturer cloud (ResMed's AirView/myAir, for example) that doesn't replace reading the card — those services show a summarized view. The card holds the granular data those apps leave out.

What files to expect (EDF and vendor formats)

Open the card and you'll see folders and files that look cryptic. Here's what they actually are.

ResMed: EDF files

ResMed stores its detailed data as EDF files — the European Data Format, an open medical standard for time-series biosignals. You'll typically find a DATALOG folder organized by date, plus an Identification file and STR.edf (the summary stream). Each night produces several EDF files covering different channels (events, pressure, leak, flow). Because EDF is an open format, ResMed data is the most widely readable across third-party tools.

Philips DreamStation 1: readable proprietary format

The DreamStation 1 (and the older System One) writes data in a Philips-specific format that is unencrypted and readable by analysis tools. You'll see folders with .001, .002-style numbered files and per-session data. It isn't EDF, but it can be parsed. Our DreamStation 1 data guide explains the layout.

Löwenstein prisma: vendor format

Löwenstein prisma cards use a proprietary layout (you may see a DCM folder and configuration files such as config.pcfg). It's vendor-specific rather than EDF, so you need software that specifically understands the prisma format to make sense of it.

A quick word on what these files contain: your reported AHI (Apnea-Hypopnea Index — events per hour of sleep), leak rate, pressure, and event types all come from this data. Keep in mind that a device-reported AHI is an estimate — the machine has no EEG to detect arousals the way a sleep lab does, so it can differ from a lab-scored number. And one trust-building point worth knowing early: a large mask leak can invalidate or under-report your AHI, because the machine can't reliably detect events through a flood of escaping air. (More on that in CPAP leak rate.)

The DreamStation 2 encryption exception

Here's the one that trips people up. The Philips DreamStation 2 encrypts the data on its SD card. Unlike the DreamStation 1 — whose card you can read freely — the DS2's files cannot be opened by OSCAR or most third-party CPAP tools. If you pop a DS2 card into a reader, you'll see files, but they won't parse in the usual software.

This became a bigger deal because DreamMapper, Philips' companion app, shut down in January 2026, leaving DS2 users with even fewer ways to see their own data. (Philips signaled migration intent for users at the time.)

So DS2 owners face a real gap: encrypted card, retired app, and standard tools that can't help. SomniCharts is one of the tools that does support the DreamStation 2, so you're not stuck. For the full background on why the encryption exists and what your options are, read our DreamStation 2 encrypted data guide. And if you're following the broader Philips story, our neutral explainer on the Philips recall covers the device-replacement context — including that an FDA inspection report and independent lab tests (the latter commissioned by Philips) raised concerns the silicone-based replacement foam could emit volatile organic compounds, including formaldehyde. The FDA did not issue its own finding that the foam releases these chemicals; it requested additional independent testing and, while that testing was pending, advised patients to keep using their repaired or replacement devices. Philips says detected levels stayed below applicable thresholds, which some independent experts dispute.

Where to upload and read your data

You've got the files — now you need somewhere to actually read them. You have a few paths:

• OSCAR — free, open-source desktop software. It's powerful but has a learning curve, does no automatic scoring, won't run on a Chromebook, and can't read the encrypted DreamStation 2. See our OSCAR software guide.
• Cloud analyzers — browser-based tools that read your card without a desktop install. They vary widely in which machines they support. Our OSCAR vs SleepHQ vs SomniCharts support matrix compares who reads what.
• Manufacturer apps (myAir, AirView) — convenient but limited. ResMed's myAir, for instance, shows a 0–100 score weighted heavily toward usage hours, with no event-type, leak, or flow-limitation detail; the formula has never been published, and you can score 100 even at an AHI near 5. See what myAir hides.

If you'd rather skip the desktop install entirely, upload your card straight to SomniCharts and get a plain-language read. SomniCharts imports ResMed, Philips Respironics (including the encrypted DreamStation 2), and Löwenstein prisma data and explains it automatically — your AHI, leak rate, pressure, event types, and flow-rate trends in language you can actually act on, all in the cloud with nothing to install. Its built-in SomniDoc assistant turns the raw numbers into a clear summary you can bring to your provider.

One habit to build from the start: don't fixate on a single night. One bad reading is usually noise — a restless night, a slipped mask, a head cold. What matters is the trend over weeks, and that's exactly what cloud reporting makes easy to see. When you're ready to interpret the numbers, our plain-English guide to reading CPAP data and what counts as a good AHI are the natural next stops.

A note on therapy goals while you read: the widely used benchmark for effective CPAP is a residual AHI below 5 events per hour — the AASM defines an "optimal" titration as reducing AHI below 5, which is also the normal range. Some clinicians aim lower (e.g., under 1–2) when it's comfortably achievable, but targets are individualized and set with your provider. Use your data to have an informed conversation with your sleep clinician — not to make changes on your own.

FAQ

Do I need a special SD card reader for CPAP cards? No. A standard SD card reader (built into many laptops, or a cheap USB one) works for all three brands. CPAP machines use ordinary SD/microSD cards; nothing about the hardware is proprietary — only the file format on some cards is.

Can I read my DreamStation 2 SD card in OSCAR? No. The DreamStation 2 encrypts its card data, and OSCAR cannot decrypt it. You'll need a tool that specifically supports the DS2 — SomniCharts does.

Will removing the SD card delete my data or break my machine? No, as long as you remove it when the machine isn't actively writing (power it off or pause therapy first). Copy the contents, then re-insert the card so the machine keeps logging.

My CPAP uses the cloud — do I still need the card? Often, yes. Manufacturer cloud services show summarized data and hide detail like event types, flow limitation, and the flow-rate waveform. The SD card holds the granular record those apps leave out.

Is the data on my card the same as what my doctor sees? Your provider typically pulls a compliance report and summary metrics. The raw card data is richer — and you're entitled to see it. Our guide on getting a compliance report explains the document side.