Cable for Chinese uSDX+ V2

I’m trying to build a serial cable for a Chinese uSDX+V2. The radio uses a Kenwood mic/speaker connection and I’m able to transmit, receive, and key PTT using the Baofeng audio cable. The radio has a CAT port that emulates a Kenwood TS-480.

Here is a diagram of the connector pinout:

I have 2 questions.

  1. I purchased the Digirig revision 1.9 configured for CI-V. Is the " Duplex serial CAT with RS-232 levels" configuration the correct configuration for this radio?

  2. What is the correct wiring for a TRRS to TRRS CAT cable? It appears like a strait TRRS cable will work when referencing the 1.9 schematic.

Thanks All!
Chris - W5CMM

Yes, you’ll need a default configuration (logic levels).
And yes, looks like the straight cable should do the business. The second ring (3.3V) will be disconnected on the Digirig in default configuration so SEND_PA signal will be unaffected.


Please post your progress.

Thanks! I’ll post the results.

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I was able to unsolder the bridges for CI-V configuration and jumper the two for the default configuration (logic level).

Unfortunately the jacks on the back of the radio are cluster so close together I can’t get both audio and serial cables connected at the same time.

I’ll going to look for a TRRS aux cable with small diameter plugs, as well as some short 2.5mm and 3.5mm extension cables with small diameter plugs.

I did verify that my soldering was correct by programming a UV-5R with Chirp, so there’s some progress.

Success! (somewhat)

I was able to trim down the plug on a 3.5 mm TRS aux cable plug with an knife enough to get both cables inserted in the radio. The extra plastic on the K connector blocks the plug for CAT.

This is the configuration I’m using in WSJT-X. You can see Test CAT is green. Bands change from the drop-down menu just fine. Unfortunately when I press Test PTT the radio goes into transmit for a few seconds and then WSJT-X throws an error. I have chokes on the TRS cable, so I need to keep troubleshooting. If I set the rig to None PTT works perfectly. So…more work to do.

I also have N1MM+ working, and it’s keying up CW. This is what the configuration looks like.

I’ll post an update when I get PTT in WSJT-X sorted.

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