Headphone jack question (Stereo In ?)

Framework Laptop 13
1

Is the headphone jack of the laptop only a headphone jack, or is it one of the kinds that can also take in a microphone signal if your headphones have both? I’ve tried looking it up myself but couldn’t find any information on it.

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2

I haven’t tested it yet, by the headphone/mic jacks are the standard now.

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3

I don’t have any microphone equipped headphones to test with atm, but the codec chip is listed by the manufacturer as supporting dual headphone/microphone combo jacks, so it should work fine.

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@Curtis_Brummitt

Yes the jack is TRRS and supports headphones, headsets/mike, line out etc. It will ask you what mode you want depending on what you plug in.

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5

Yes, it supports headphones with mics. But (at least for laptops with the Realtek codec) it needs some special configuration in Linux for the mic part to work.

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6

Can i put a line level input to it out of a musical instrument device?

8

In my experience, with the 92HD95:

  • The jack supports TRRS connections of the common left-right-ground-mic standard. This can thus have a stereo output and mono microphone input simultaneously.
  • When a jack is plugged in, it is possible to switch between headphone and internal speaker output.
  • When a jack with a microphone is plugged in, it does not appear possible to switch between the external and internal microphone. Trying to change the settings just gives the same external microphone signal.
  • The microphone cutoff switch affects the internal microphone only.
  • Looking at the codec chip documentation and messing with alsa and pipewire, it would appear that, unless Framework has done something different, the jack would not support stereo line in (eg, using the TR-- for input), and would not support stereo microphone input in any other way. All of these would be uncommon: the only case I can remember supporting things like these was, if I recall, on a Macbook Pro, and that jack was also a combination with an optical in/out, if I recall correctly.
  • The internal mics do appear to have a real stereo input, but there appears to be no way to have external stereo input.

Realistically, for other use cases, it probably makes more sense to use a specific USB-C audio interface.

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9

Because the mic switch is hardware, there is no way to make it silence audio jack mics, then? No software involvement?

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My understanding is that the mic switch is a direct, physical, hardware cutoff, actually cutting the electrical connection, and that it’s actually located quite close to the internal microphones. In principle, you could have a cutoff switch design that would act as a similar hardware cutoff for both, but the layout would be a mess, because the jack and internal microphones are quite far apart.

I actually think that, with the way the switch is implemented, there’s no simple way to determine in software whether the switch is on or off, unlike the camera switch, where the camera device disappears. So even a software-based cutoff tied to the switch would be challenging.

Edit: actually, it seems s though I’m at least partially wrong about this. There is signal for the microphone privacy switch state that goes to the webcam interface connector: this is pin 26 in the pinouts document, though nrp has a pinout list with notes here.

For the FW16, it’s possible that a different design of expansion card audio jack could include a separate cutoff switch on the card, which would be comparatively easy.

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Or maybe there could be a dipswitch card that controls things like wifi, bt, mic, speakers, or other things through software