There are two major schools of spo2 sensors in terms of working machenism:
1, Analog and digital;
When we refer to "analog" spo2 sensor, the spo2 sensor is equipped with a photodetector; and when we refer to "digital" spo2 sensor, it is equipped with a digital light-to-frequency converter.
Technical data are available in OSI company website and Texas Instruments website:
2, How to tell?
As you can read from the technical data, the appearance of the photodetector chip for analog and digital spo2 sensors are different;
3. What for?
Now many Chinese OEM patient monitor manufacturers uses light-to-frequency converter as photodetector, such asContec, Meditech, Creative, Comen, Biolight, and their spo2 sensors usually more or less the same, for example Lemo 5 pins single notch connector spo2 sensors with digital spo2 sensor, usually works with Contec, Biolight, Meditech .... patient monitors.
So the photodetector is going to help you to decide what spo2 sensor to use. For example, Comen spo2 sensors usually 6 pins Lemo connector, single notch, however, the newer models usually use digital spo2 sensor, which is with light-to-frequency converter equipped, and the older models usually with analog spo2 sensors, so normal photodetector is equipped.
Conclusion: sometimes if you are not sure which sensor your monitor use, please take picture and send us the picture of photodetector to firstname.lastname@example.org , it will help.