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I plugged the 3.5mm jack into a USB-c adapter, and into the PC.

It is recognized as headphones, while my internal mic is recognized as the mic. How can I switch it so the plugged USB-c is recognized as the mic instead of headphones?

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Here is what I have tried:

1- Updated the Lenovo ThinkPad p52 from the manufacturer's website with auto-scan to the latest all

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2- I have the latest windows update

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3- Disabled fast startup

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4- uninstalled and reinstalled everything under "sound,video and game controllers" and "audio..."

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5- unplugged the 3.5mm jack mic from usb-c adapter and plugged to a splitter, and straight into the 3.5mm of the PC. Nothing changes, PC speaker becomes the PC, and internal mic stays as the mic.

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6- Installed r2.81 which causes the following error when after I restart the PC. So I uninstall 2.81 and install r2.82 instead.

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7 - Installed r 2.82 - back to square one. Here is what the Realtek folder looks like

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8- This should have been the input device, but detected as output device

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Some other screenshots

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The only time it worked is when I plug the microphone jac into the HP Elite docking station jack, and then the USB-c of the docking station into the Lenovo usb-c. Then it recognizes it as a microphone.

In the below image, the far right is the microphone, and the middle is the splitter and the far left is the usb-c adapter. I was trying these 2 different methods since I thought jack might be broken on the laptop.

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How can I use the USB-C adapter or the lenovo built-in headset with the splitter to let the PC recognize its a microphone and not a headphone?

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  • It's probably the pinout. See superuser.com/questions/1568508/… and sound.stackexchange.com/questions/48560/… for some clarification
    – Tetsujin
    Jan 24, 2021 at 13:41
  • @Tetsujin I am not sure I understood how the solution to both these questions you linked would help me. I do have the "headset splitter", but still it would recognize the internal mic instead of the mic plugged into the splitter. That being said, the headphone plugged into the splitter is recognized as the headphone. Jan 24, 2021 at 14:44
  • If the pinout doesn't match it won't recognise it correctly. As I don't know the pinout of any of your components, you'll have to check that yourself.
    – Tetsujin
    Jan 24, 2021 at 15:57
  • @Tetsujin I have added three new pictures, the usb-c adapter, the microphone and the headsplitter. Kindly take a look. Jan 24, 2021 at 16:27
  • I'm afraid that without being able to see the pinouts of the sockets too, we're no closer. Strictly speaking, we allso need to know where the contacts connect, not just how many there are.
    – Tetsujin
    Jan 24, 2021 at 16:30

1 Answer 1

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Solution

Use your audio splitter, and connect both the mic AND some headphones to it. Connecting only the mic will never work.

Why? Your audio interface is not suicidal.

(On some older hardware, or when using a Mac, you might still get some strange audio effects caused by basic hardware incompatibility issues. I won't go into this.)


Explanation

This is all about electric circuitry. It can't be resolved by software. Jack connectors are 'dumb', and there's no possible way your mic can tell your PC "I'm a microphone".

3.5mm Jack connectors come in two basic flavours: four-pin and three-pin, as on the below image. (OMTP four-pin connectors have mic and ground inverted in respect to CTIA. Some old phones use OMTP) Jack connectors

A four-pin jack plug, as on your PC and USB-Adaptor, for obvious reasons needs to be able to handle BOTH CTIA-Headsets as well as normal Headphones. It can't handle just a microphone, though.

Headphones as well as Mics are electric circuits, with the current flowing from left/right/mic connector to the grounds connector.

As you can deduct from the image, a normal headphone connector will bridge pin 3 & 4 with its ground connector. If the mic pin would be active while you plug-in a headphone, this would cause a short circuit between pin 3 & 4, immediately frying your audio device and probably taking down your whole machine.

For this reason, for the mic pin to be activated, two conditions must be met:

  1. Current flowing from both left(1) & right(2) to ground(3)
  2. NO Current flowing from neither left(1) nor right(2) to mic(4)

Condition 2 is not sufficient: a defective headphone could still fry out the device.

Once both conditions are met, the mic pin is activated, and your device driver will tell Windows your OS that there's a microphone connected. But there's no way your device will activate only the mic pin, while left & right pins are inactive: your device is not suicidal.

So, if you just plug in your mic, your device will tell the OS to register a headphone, as there's no way to tell the difference between a headphones and a mic connector.

And if you use the audio splitter but only connect the mic, your device will still say it's a (defective) headphone, as it detects a connector plugged in, but condition 1 is not met: you need to plugin a headphones, too, so your device will detect that the left & right circuits are closed.

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  • Wow! Thank you very much! I appreciate the time you took to explain the physics behind it. Dec 14, 2021 at 16:53
  • This may explain why my mic does not work on my new HP laptop. However, when I connected my mic to my old Dell Precision 5520's 3.5mm jack, it used to ask me whether this is a mic or headphones. I could then choose "Mic" and the mic worked. Did it work somehow differently from your explanation? Sep 22, 2022 at 19:56
  • @AlwaysLearning If your driver does not support it, there's no way your system could know you connected a microphone. Use a splitter, or a USB-adapter (they are cheap!) instead
    – 1NN
    Sep 22, 2022 at 20:02
  • The point is that it worked on Dell without a splitter and without headphones, which seems to contradict what you explained in your answer. Sep 24, 2022 at 18:20
  • @AlwaysLearning as you wrote yourself, your Dell had a driver which asked you what you'd plugged in, which means that your hardware could switch between the two possibilities. But if your OEM has not created that possibility, there's no way you can create that later on. For more details, post a new question.
    – 1NN
    Sep 24, 2022 at 20:52

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