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How to Use Thinklink

Before getting started....


First, ensure that you have enabled access to the microphone when you download the Thinklabs Stethoscope App.  


During installation, it sometimes asks if you're willing to give access to the mic and sometimes not. When installing, you have to say "Yes."  Apparently, iOS sometimes asks this question and sometimes not, as well.  The usual problem with the App is Apple and audio input source control. If you're getting room noise, the input isn't switching. Apple doesn't allow Apps to control the input source and want to have their system do this automatically. Unfortunately, it doesn't always work!



To use Thinklink, follow the steps below, in the order they are written:


1. Connect the One to the lower left jack on the Thinklink box, which shows an icon that looks like the profile of the One. Use the long 3.5mm male-to-male audio cable supplied with the Thinklink.


2. Connect headphones (earbuds or others) to the upper left jack, signified by a headset icon.


3. Connect the short 3.5mm male to male audio cable (or right angle male-male connector) to the lower right jack on the Thinklink. This is identified by a rectangular icon, indicating a smartphone or tablet.


4. Set the SOURCE switch to the middle position.


5. Set the MONITOR switch to the left position so you can monitor the stethoscope sound during recording.


6. Launch the Stethoscope App on your device. Recording commences automatically. Tap the screen to stop recording.


7. Plug the 3.5 mm short cable (or right angle male-male connector) into the iPhone/iPad headset jack. When you make this connection, observe the upper left region of the screen for a "Headset" message. This indicates that the iPhone/iPad has switched its audio source from the built-in mic to capturing audio from the headset jack, i.e. the stethoscope. If the message indicates "Built-in Mic", remove the plug and reconnect. (The device makes an automatic selection.)


8. Turn on the One and begin recording (tap the red button icon on the top right of the screen). Adjust the volume on the One to a medium level. If the One is too loud, the App will indicate this with a "Stethoscope Too Loud" message. Set the volume as loud as possible without triggering this message.


9. Touch the screen to stop recording. Zoom in and out with thumb and forefinger to display the desired audio segment. Then touch Edit [E] > Trim to trim the recording to the displayed segment.


10. Slide the MONITOR switch to the far right and touch the Play icon (>) to play back the recording and monitor it via the headphones. Note: Slide the MONITOR switch to the middle position (not right position) in order to hear the stethoscope in one ear and the playback in the other. This is primarily used for telemedicine videoconferencing applications in order to hear the local stethoscope and the remote clinician simultaneously.




  • If you are seeing a flat line when recording, then your Mic is not turned on for the App. Go to iOS Settings and allow access to the mic for this application.

  • When starting a recording, the App will initially sense the signal level and adjust recording sensitivity. You may observe a noisy signal during this period.


NOTE: The iPhone/iPad has a mind of its own when it switches from built-in mic to headset. If the switchover does not occur, you will record room sound instead of stethoscope sound. If this occurs, try disconnecting the iPhone/iPad and then reinserting the plug. Make sure that switches are SOURCE=middle, MONITOR=left and that the stethoscope is turned on.


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