Pinout for disposable SpO2 monitor (Masimo LNCS Adtx)?

When I was in the hospital recently, they used a "disposable" blood oxygenation (SpO2) fingertip monitor. They let me take it home with me afterward (otherwise they'd just discard it!). I would like to find a pinout for it and see what else I can do with a paired LED/photodiode.

The model is Masimo LNCS Adtx. The connector is rectangular, but with a "9-pin D" style of pins -- top row five, bottom row 4, and with the second pin in each row removed for keyed insertion.

I've been able to find operator's manuals and user guides on the Web, but nothing technical. Anyone out there with medical equipment experience who can point me toward a spec?

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frollard7 years ago


Wikipedia of sp02 (saturation of peripheral o2) stated it was measured with a pulse oximeter.

Googling pulse oximeter pinout gave me the allpinouts page. :D
frollard7 years ago
Just asked my paramedics (standing next to me)

Their sp02 meters are the same, db9 connector with 2 pins missing. It stands to reason that the 2 pins by themselves would be power, and the rest for your fancy differential signals. (this is on a non-disposable unit).

http://www.welchallyn.com/documents/Patient%20Monitoring/Vital%20Signs%20Capture/Spot%20Vital%20Signs%20LXi/usermanual_20080121_spotlxi.pdf might have info...

via http://www.welchallyn.com/products/en-us/x-11-ac-100-0000000001118.htm
kelseymh (author)  frollard7 years ago
I knew we'd have an expert floating around here somewhere :-) Thanks for that document! I had actually found it as one of just three hits on my first Google search (how's that for good keyword usage :-). Unfortunately, it doesn't call out the signals on the SpO2 connector.
Yeah, I only skimmed it - perhaps a patent search would help? That doc or the dongle itself probably has the patent number(s) on it.
kelseymh (author)  frollard7 years ago
Congratulations on finding the answer :-) I had tried multiple Google searches for "SpO2" and "blood oxygenation", but didn't know that "pulse oximeter" was the right term. Occasionally, even Homer nods...

And there's a good Google search for the young and ignorant...Do not ask me to explain it for you :-)
to confirm my search terms: Homer...odyssey or simpson? :D
kelseymh (author)  frollard7 years ago
:-P Try the phrase itstelf, "even Homer nods". The first three hits explain it, and the fourth gives the correct original phrase.
but, but, this is instructables. It's easier to ask in broken sentence structure and misspellings than to search.
lemonie7 years ago
I guess that ultimately you've paid for this so it's only fair you keep it (useless or useful). Strikes me they're deliberately being extravagant for financial gain.... (but I may be wrong)
I can find this: http://www.oximeter.org/pulseox/principles.htm, and I think the pin-out is probably fairly basic, it's the rest of the device that does the work?


(Masimo, yes I know of them)
kelseymh (author)  lemonie7 years ago
Thanks for the link. I understood the basic theory behind SpO2 measuring, but not those details. I didn't know the system was simply as doubly-differential spectrophotometry; doing the pedestal subtraction with the live data is really elegant.

The pinout kind of has to be "basic" -- there are only a maximum of five active signals, after all, but I'd like to know which is which...
If you picked the case apart I'm sure it would be obvious, but I'm guessing it's glued or ultrasonically-welded together. A multimeter might give you some clues, my mind is leaning towards IR emitter / receiver - 2-pin and 3-pin semiconductors aren't they? L