Phone 3.5mm output to mic input converter

The goal here is to take a conference call that the cell is called into, plug in a 3.5 (normally would be my earbuds w/ mic built in) and run that into the laptop 3.5 so that OBS can see it as an audio input and retrieve the call audio.

So I imagine its not just a TRRS to TRRS extension, but some kind of TRRS cross-over TRRS adapter. Figured the interwebs would be full of results but the only thing I found was this:

Its that or I just hack up a TRRS male to male extension but I don’t want to mess it up (those wires are crazy thin, color coding is meh).

Correct, with an extension you’d just be plugging your phone’s mic input into your laptops mic input.

If I’m looking at it right that kit basically connects the right channel from one side to the mic channel of the other side. Although it looks like it might be intended to be used one way or something, there are more components on one crossover channel.

If I have understood correctly, although I can get it wrong because my brain is only working at 10%, in theory it would look like this.

Instead of physical headphones and your ears, the PC will listen to the mic input.


So much theory … In practice it is different. Does the phone accept the signal, will the stereo work, will the quality and audio level be ok, if the cable that is not officially bi-directional will work in the other direction …


3.5 M/M


Or…



https://www.circuitbasics.com/how-to-hack-a-headphone-jack/

What I had in mind:

No need for me to be able to take part in the call, just capture the call. But @TimHolus you have me thinking go the extra mile and adapt it further so I can also have my headset plugged in and working as well I suppose. Some of those adapters you posted or ones similar could maybe be used in conjunction to the cross over so that I can still be part of the call, but the main hurdle is to literally cross the tx and rx so to speak.

Looking at the Inductive Twig schematic:

I don’t like the jack representation, but it looks like it simply crosses over mic and audio out and hence the attenuation circuit.

I guess I could also buy two of these
https://www.digikey.com/products/en?mpart=BOB-11570&v=1568

and bridge them via the same attenuation circuit whilst crossing the appropriate wires. I’ve got a pile of resistors and caps laying around.

I hope not, it won’t serve my purpose. But then again with the header board one can assort the crossing-over as they please.

I have an email sent out to them asking about using their board for my purpose. Hopefully they are helpful and come back with what wires from a cut/flying lead 3.5mm TRRS harness needs to be soldered to what header. Plenty of schematics online to teach me this but would be easy on my brain if they fill in the detail.

Speaking of that, what is the goal? Maybe audio improvement? Recording phone calls? Or piping another source into a conference software?

Screen capturing training being shared to the team on OBS but also want to capture the trainer’s voice (not me) and other’s audio on the call.

Already validated a working OBS input by plugging in my earbuds/w mic (TRRS) into the docking station and setting up the source in OBS.

I know if I want what I say on the call captured I think it complicates things, as it will not loopback out of the audio out. Maybe a simple Y splitter with speaker part cut so cross-over mic and earbud’s mic can y together. Its analog so should be fine right? But its not a deal breaker.

Heck I can just add my desk mic as yet another Audio source in OBS, so this should be a non-issue.

  • inductivestick got back to me already- sounds like its a go, I bought two kits, one for another co-worker.
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You could say at the very beginning that you have a single trrs in your laptop… :slight_smile:
I looked at it as two trs problem / solution. :wink:

recap_s2_diagram_754_299_3-e1406176642721


RECAPS2-block-diagram
Then you need…, yes high price but ready to use straight from the box. :wink:

Or you will do as you decided with these pcb. :slight_smile:

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That sir gets a solution. It is pricey, I’m going to see if I can expense it.

That’s right, unfortunately high price. It is possible that you can find something similar cheaper but you need to look. If you fail to do it yourself based on what you ordered, you may have no choice but to invest or get the company to buy it :wink:

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This has been a surprisingly niche product/use-case.

I have some adapter plugs similar to this:
image
With that, you get the 4 poles as screw terminals.

While it may be tempting to just cross the right and left audio outputs from your phone into the mic-in clamp, that is not advisable. The blue jack in the back of motherboards is line it. This is MIC-in.
Depending on the output of your phone, you want between 10k Ohm and 500k Ohm from what is essentially line-out to the mic-in of your laptop.

What complicates matters is the fact Ground and Mic on TRRS-plugs are not standardized. The following schematic may be outdated:

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I wonder if you can use Bluetooth?

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There is a $100 Bluetooth recording option on Amazon. Bluetooth is annoying though, I like the idea/reliability of a wired option.

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Jeez, I was thinking more something like having an a2dp sink on your computer that you can use as any audio interface. I think you get this with Ubuntu out of the box.

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Nice, I’ll check out if my work laptop can support this

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