External Microphone options

[JJon010b]

Hello I have a question regarding external mic options, is it practical or possible to wire an lapel microphone with 3.5 mm trs connector the mic/key port of the (tr) uSDX, if so what would the pin out be?
Thank you in advance for any an all help in this matter.

[Cthulhu]

I have slightly modified the standard adapter - added a button. I use it with a computer headset Sennheiser. I think any headset will do. Mine has a noise cancelling microphone. I have not had many SSB connections, but all heard well, the reports are good

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[JJon010b]

Preview: Pin out for external mic
Hello Cthulhu, looks like a nice interface mod for (tr) uSDX, I have a separate ear piece for audio out, the mic/audio connector interface is my concern, question can you provide a pin-out diagram, I'd like to try it with my lapel mic. Thank you in advance.

[JJon010b]

When I attempt to plug in my lapel mic which is terminated in a trs 3.5 mm connector, the unit goes to transmit mode, I have the (tr) loaded with a 50 ohm dummy load to prevent transmission.

[Cthulhu]

Look at the wiring diagram for more clarity:
https://dl2man.de/4-trusdx-manual/

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[JJon010b]

Thank you kindly for your response.

[dogbit]

Hi there,
What should be the peak-to-peak voltage at the microphone input when using the external microphone?
Thanks in advance for any info.