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I've ordered one of these: https://www.amazon.com/gp/product/B074Z1LDY2/, a tactical throat mic (and earpiece speaker) which is intended to be used with Kenwood two-way radios (and other compatible models). I'm interested in using this with conventional CTIA TRRS inputs/outputs as found on cell phone and laptops.

I know the pin-outs are incompatible as they are so I know I need to re-wire at bare minimum. What I'm trying to discover is how to tell if I need some capacitors and resistors or a full, externally powered circuit to support the mic (my primary interest, the speaker is less interesting to me).

I have a mid-level multi-meter and no oscilloscope. I know the pin-outs for these generally:

Kenwood two-way pinouts: Kenwood two-way two-pin pinouts

CTIA cell phone TRRS pinouts CTIA standard TRRS pinout

How can I best reverse engineer what the two-way radio mic is expecting and how to hook it up to what the cell phone is providing WRT to power? I've not been able to find any references on Kenwood two-way radio mics. Any tips for strategy to make this work, particularly not requiring more specialized testing equipment, would be very helpful. Also, any warnings and strategies for not damaging equipment would also be helpful. ;-)

[Edit: I've come across this which is basically the opposite of what I'm interested in doing but may give helpful context to someone with more insight that I have. http://www.n1gy.com/headset-adaptor-for-kenwood--baofeng-and-wouxun-hts.html ]

Follow-up:

Works perfectly as described by @JRE below. The 3.5mm pin plugs directly into the breadboard jack on the right; the 2.5mm pin plugs into a 2.5->3.5mm adapter and then plugs into the jack on the left. The wiring specifics should be discernible via the photo.

enter image description here

Aaron
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2 Answers2

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Let's get a couple of things together here.

First, a diagram of how to connect the Kenwood connector:

enter image description here

That image came from here.

Second is how to connect to an Android phone:

enter image description here

Your throat microphone is most likely a two terminal electret microphone, so Note 2 from the Kenwood diagram should apply and there will not be a 10uF capacitor in the microphone line.

All you should need to do is to connect the microphone line from the headseat to the Android microphone line. Then the microphone ground to the Android ground. The microphone ground is the ground connection on the smaller (2.5mm) plug.

The Android diagram shows where to connect the microphone wires.

Once the microphone is connected and plugged in to your phone, the phone should recognize the headset and switch to headset mode.

That should do it.

Connect the earphone to left or right and ground if you need the earphone.

If you've never used a throat mic before, then you should be ready for a surprise.

Throat mics don't sound like regular microphones. Throat mics pickup pretty much just the vibration from your larynx. All the aspirant sounds ("S" and "Sh" sounds and the like) will be very weak or not present at all. People may have a hard time understanding you.

JRE
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For anyone visiting this page looking for general radio headset wiring information...

Almost all modern two-way radios expect a standard electret mic as the mic input - a two wire mic with internal fet amp. These mics are ubiquitous and need a few volts, which the radio provides, to power them, phantom power if you like. The voltage is not critical. A series capacitor on the mic input will prevent block DC and prevent the Mic working.

The same radios will also accept a Dynamic mic. These do need a series capacitor to block the DC phantom voltage from Mic.

Electret Mics give a nominal output of 30-100mV RMS and Dynamic Mics 5-15mV. Most radios have some basic Mic AGC and Limiting so are very forgiving of the order of magnitude of Mic levels.

If you need more cable and wiring data for

radio pinouts you can find them here.

schematic

Bivviboy
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