Question: What type of microphone do you support on the 4KXUSB3 and 4KXPLUS?
The devices support electret microphone (no phantom power supported). The bias voltage sent to the microphone is about 0.9V. The pinout of the audio jack is (left side INOGENI device, right side microphone):
Please note that both tip and ring are usually shorted together on electret mic with this kind of audio jack, so the exact pinout between TIP and RING is not a concern.
Examples of microphone that should work (not officially tested):