Philips DreamStation 1 & System One: SD Card Data and How to Read It

If you use one of Philips Respironics' older machines — the DreamStation 1 or the earlier PR System One — you are in a fortunate position when it comes to your data. Unlike the newer DreamStation 2, these machines write detailed therapy data to the SD card in a format that third-party tools can actually read. This guide explains what's on that card, where to find it, and how to turn it into a clear picture of your night.

DreamStation 1 and the legacy PR System One

Philips Respironics has shipped two generations of consumer-friendly home machines that share a similar data philosophy: the System One family (the squat, rounded units from the early-to-mid 2010s) and the DreamStation 1 (the flatter, modern-looking unit that replaced it). Both come in CPAP, Auto (APAP), and BiPAP variants.

For data purposes, the important thing they have in common is the SD card. Each night, the machine records:

• Summary data — usage hours, your reported AHI (apnea-hypopnea index, the number of breathing events per hour), and pressure averages.
• Detailed event data — obstructive apneas, clear-airway (central) apneas, hypopneas, RERAs (respiratory effort-related arousals), and periodic breathing, each time-stamped.
• High-resolution waveforms — flow rate, pressure, and leak over the course of the night (when the card has captured them).

That third category is what separates a real analysis from a usage tracker. If you want a refresher on what these numbers actually mean before you dig in, start with How to Read Your CPAP Data.

The key fact — DS1 data is NOT encrypted

Here is the single most useful thing to know about the original DreamStation and the System One: their SD-card data is not encrypted. The files are written in Philips' own binary format, but that format is documented well enough that free and commercial tools can decode it. Your therapy history belongs to you, and on these machines you can read it without asking anyone's permission.

This is a meaningful contrast with the newer hardware (more on that below), and it's the reason the DreamStation 1 remains a favorite among people who like to understand their own therapy. You can:

• Read it in free desktop software like OSCAR.
• Upload it to a cloud analyzer.
• Keep your own long-term archive independent of any manufacturer app.

SomniCharts reads DreamStation 1 SD-card data and explains your night in plain language automatically — and it keeps that history even if you later switch to a different brand of machine. SomniCharts imports ResMed, Philips Respironics (including the encrypted DreamStation 2), and Löwenstein prisma data, so your record doesn't reset every time your equipment does.

Where the SD card lives (behind the water tank)

On the DreamStation 1 and System One, the SD card is not in an obvious slot on the back. It sits behind the water tank (the humidifier chamber). This trips up a lot of people, so here is the sequence:

1. Turn the machine off and unplug it. Let it cool if it's been running.
2. Remove the humidifier water tank. It slides or lifts out from the side of the unit; empty any water first.
3. Look into the now-exposed bay. With the tank out, you'll see the SD card slot on the side of the device housing.
4. Push the card in gently to release it (it's a push-push slot), then pull it out.
5. Read the card in your computer's SD reader (or a USB adapter).
6. Eject the card properly in your operating system before removing it, and slide it back into the machine the same way when you're done.

A few practical notes:

• Leave the card in the machine almost all the time — it needs the card present to log data. Only remove it when you want to read it.
• If your laptop has no SD slot, an inexpensive USB SD-card reader works fine.
• Don't format or "clean up" the card. Just copy the files off or point your software at the card directly.

For a brand-agnostic walkthrough of pulling and reading cards across machines, see How to Download CPAP Data from Your SD Card.

DreamMapper vs detailed data

The DreamStation 1 also pairs with DreamMapper, Philips' consumer companion app. It's helpful to understand exactly what DreamMapper does and does not give you.

DreamMapper is built to encourage adherence — it tells you whether you used the machine and gives an at-a-glance impression of how things are going. What it doesn't do is show you the texture of your night: which kinds of events you're having, whether leak is undermining your numbers, or what your airflow actually looked like. Those answers live on the SD card.

One important development to plan around: Philips shut down DreamMapper in January 2026. If you'd been relying on the app to keep your history, the SD card is now your durable source of truth — another reason to read the card directly and archive it somewhere lasting. (Consumer scorecard apps in general are thin on detail; myAir & DreamMapper Limitations covers why.)

When you do look at the detailed data, a couple of trust-building points are worth keeping in mind:

• Device-reported AHI is an estimate. Your machine flags events from airflow and pressure signals alone — it has no EEG, so it can't see arousals the way a sleep lab can. A lab-scored AHI and your machine's AHI won't match exactly, and that's normal. The widely used benchmark for effective therapy is a residual AHI below 5 events per hour; some clinicians aim lower when it's comfortably achievable, but goals are individualized with your provider. See What Is a Good AHI on CPAP? for the full picture.
• Large leak makes the AHI untrustworthy. When mask leak is high, the machine can miss events and under-report your AHI — so a "good" number on a leaky night isn't reassuring. Philips reports total leak (intentional vent flow plus any unintended leak), which reads differently from ResMed's excess leak figure, so don't compare the raw numbers across brands. CPAP Leak Rate explains acceptable ranges and fixes.

If you ever notice clear-airway (central) events climbing on these reports, that pattern deserves a conversation with your clinician rather than a do-it-yourself fix — Central Apneas Showing Up on CPAP explains why.

DS1 vs DS2 data access (the crucial contrast)

This is where the original DreamStation and the DreamStation 2 part ways, and it's the contrast most people are searching for.

The DreamStation 2 writes its SD-card data in an encrypted format. That means OSCAR and other community desktop tools cannot open it — a real change for anyone who upgraded expecting the same open access they had on the DS1.

SomniCharts supports the DreamStation 2 anyway, because it decodes the DS2 format directly, so DS2 owners aren't locked out of plain-language analysis. But if you're choosing between machines or wondering why your new unit "stopped working" with OSCAR, the format change — not your hardware — is the reason. The full explanation, and the options DS2 owners have, is in Philips DreamStation 2: Why Its Data Is Encrypted and Your Options.

This difference is also why keeping your own archive matters. If you move from a DS1 to a DS2 — or to a different brand entirely — your DS1 history shouldn't vanish. Switching CPAP Brands? Keep Your Data History Across Vendors walks through preserving a continuous record.

A note on the 2021 foam recall

Many DreamStation 1 and System One units were caught up in the 2021 Philips Respironics recall, which centered on the polyester-based polyurethane (PE-PUR) sound-abatement foam used inside the devices. The foam could degrade and shed particles or release certain gases, and Philips recalled the affected machines for repair or replacement. If your machine was part of the recall, you've likely already gone through registration and a remediation step.

There was also a follow-on question about the silicone-based replacement foam used in repaired and new devices. To state it accurately: an FDA inspection report and independent laboratory tests (the latter commissioned by Philips itself) raised concerns that the silicone foam could emit volatile organic compounds, including formaldehyde. The FDA did not itself conclude that the foam releases those chemicals; rather, after a silicone-foam device sold outside the U.S. failed one VOC test, the FDA requested additional independent safety testing and, while that testing was pending, advised patients to keep using their repaired or replacement devices. Philips maintains that detected VOC levels stayed below applicable toxicological thresholds, though some independent experts dispute which thresholds apply.

The takeaway for this article is narrow: the recall is about hardware and materials, not about your data. Your SD card still records and stores therapy data the same way, and reading it is unaffected. For a neutral, fuller account — including what it means for your records — see Philips Respironics Recall, Explained Neutrally. Any decision about whether to keep using, repair, or replace your specific device is one to make with your clinician and based on Philips' and the FDA's primary guidance.

Frequently asked questions

Where is the SD card on a DreamStation 1?

Behind the humidifier water tank. Remove the tank to expose the card slot on the side of the device housing, then push the card in to release it.

Can OSCAR read DreamStation 1 data?

Yes. DreamStation 1 and System One data is unencrypted, so OSCAR and other third-party tools can read it. (OSCAR cannot read the encrypted DreamStation 2.) See the OSCAR CPAP Software Guide.

Why can't I open my DreamStation 2 data the same way?

The DreamStation 2 encrypts its SD-card data, so community desktop tools can't decode it. Cloud tools that support the DS2 format directly — including SomniCharts — can still read it.

Is the DreamMapper app enough to understand my therapy?

For adherence, yes; for detail, no. DreamMapper shows usage and a summary AHI but not event types, leak detail, or your flow waveform. With DreamMapper shut down as of January 2026, the SD card is now your durable, complete record.

Does one bad night's data mean my therapy is failing?

Not necessarily. Single-night numbers are noisy; trends over weeks are what matter. Look at how your AHI, leak, and pressure behave across many nights, and bring those patterns — not one outlier — to your provider. Why Does My AHI Change Night to Night? explains normal variation.