Can I ask a Stupid Question?

[greatunclebill]

For it to retain the memory, it is one of two things:

A battery (which will eventually fail)
An itty bitty hard drive called a Flash Drive which retains memory even if unpowered (like a USB memory stick)

Did you ever plug your old machine in to see if it retained the date and/or time?

Do you feel intrigued enough to take it apart and see it's innards? (if you do take it apart, take photos and share!)

respironics don't have a visible clock or any way to set a clock that i know of. the clock would be useless in the old machines because they don't display anything about time.

[JumpStart]

For it to retain the memory, it is one of two things:

A battery (which will eventually fail)
An itty bitty hard drive called a Flash Drive which retains memory even if unpowered (like a USB memory stick)

I don't believe any kind of static memory - rom, flash, etc. - would be useful in retoring date or time data by itself. It would of necessity be some form of active programming which can recognize the changing time (and therefore changing date) since the machine was stopped and main power discontinued. And that would require power. If you stopped a machine with a flash or other static memory, and later started it, it would not be able to recognize the difference in time between when it was last stopped and subsequently started. As I said, unless there is a battery, or other form of power, I think the most likely source of time/date recognition described in the intial post would be some form of magic! :grin:

[Sleepster]

My PRS1 machine runs about four minutes fast. To compensate, I have bedside clock set four minutes fast. That way, if I wake up and think I've had an apnea I can jot down the time and later check using SleepyHead to see if I really did have one.

[zimlich]

There are no stupid questions in the quest for understanding/knowledge.

[pk6301]

When I get the time Monday morning I will call Respironics 1-800 number and ask tech support.. It will give them a nice change from the normal questions and complaints they normally get through the week

[pk6301]

Well I found out a plausable answer to my question.. I talked to my DME tech this afternoon, He says there is a little chip in there that senses the date and time when you plug it in. (it is just like those alarm clocks you can buy that do the same thing, plug them in and they will automatically set the date and time for you).. I do not know if he is feeding me a line, but is a very plausable answer to me, I tried to call respironics 1-800 # but they were actually no help.

[PaulaO2]

An internal atomic clock?

Funny. What if your bedroom is further inside the house and it can't get a signal??

Or, if your house is like mine, located in a dip so only the atomic clocks on the south side of the house get a signal?

[SuperSleeper]

Well I found out a plausable answer to my question.. I talked to my DME tech this afternoon, He says there is a little chip in there that senses the date and time when you plug it in. (it is just like those alarm clocks you can buy that do the same thing, plug them in and they will automatically set the date and time for you).. I do not know if he is feeding me a line, but is a very plausable answer to me, I tried to call respironics 1-800 # but they were actually no help.

If that DME is talking about something similar to an "Atomic clock" (radio signal clock), where it receives radio time sync info from an actual atomic clock like the one in the U.S. that broadcasts from Fort Collins, Colorado, I'd say that is complete nonsense.

Just too much that can interfere with the radio signal. Heck, in the U.S., most consumer-level atomic clocks have to be mounted quite high on a wall and near an outside wall and with no major obstacles between them and where the radio signal is coming from. If that's the way they do it, it's not going to work for about 70% of households.

If any of these CPAP machines had atomic-clock-like time sync ability, you can bet the farm that they would market that feature at every opportunity, and I've never heard so much as a peep about this type of thing.

Methinks your DME is misinformed.

[Sleepster]

I have a watch that sets itself using the radio signal from the NIST is Boulder, Colorado. They used to be a phenomenon, but are now run of the mill.

The thing is, it works. Meaning it keeps the correct time. The PRS1 doesn't. It runs approximately four minutes fast and has for the entire four months that I've owned it.

It must be that it has a small button cell battery on its circuit board.

I've heard that technicians can set the time and update the firmware with a special cable that connects a laptop to a socket in the botom of the machine. I see no such socket, though! There's a small removeable panel surrounding the slot where the SD card is inserted, but I see no socket behind that panel, either!

[SuperSleeper]

Yep, I think the atomic watches work better than the atomic wall-clocks or alarm clocks designed for inside the home. With a wristwatch, since you're generally outside at least once a day or so with it on, it can get the radio signal from Colorado rather easily (no walls or other obstructions shielding the signal from your watch). A watch can keep incredibly accurate time due to being synced up so often.

But, in order to get that same regularity of time syncing on my CPAP machine, I'd have to take it outside my home and plug it in... in my older home, the rather weak NIST radio signals just don't penetrate the old thick paster and wood walls easily.

Newer home construction techniques probably have less interference with the radio signals than older homes that were built to last.

And that's assuming that a CPAP would have atomic-clock capabilities, which I don't believe they do.