APRSDroid Audiocable ( 3.5mm 4-pin / TRRS ) for Kenwood/China handy

Tested with various handy

This is a short post on how to do a DIY audiocable for APRSDroid on Kenwood / China handy type ..

We use the Yaesu VX-8G as the receiver for our APRS test and tested with a few common China handy like Wouxun and TYT.

Thanks to info from 9W2KHN, he mentioned this site have made an audiocable for TRRS phones.
https://github.com/johnboiles/BaofengUV5R-TRRS/blob/master/README.md

There are basically two types of connectors for the four pin 3.5mm plug.. the only differences are the Ring-2 and Sleeve ... either mic or ground.

4-pin 3.5mm pinout

Kenwood / China PTT pinout

As most of the phones are either Samsumg, iPhone (including XiaoMi ), we decided to make the audiocable for Samsung/iPhone called the TRRS connector.

I did not follow the components used by the circuit on the above mentioned site but just the connection. Do NOT max out your handy volume...you might blow your Android smartphone microphone.

For the handy settings, turn ON VOX to 3 to 5 ( depending on the handy sensitivity ) ...

If you are not getting anything out from the radio, change your APRSDroid Preferences on the following :-

Connection Protocol :- AFSK via Speaker/Mic
Connection Preferences :- Frame Sync Prefix ( default is 1000ms, you can change to a higher value if your handy is not triggering the VOX within 1 secs )

To troubleshoot, you can hear the output sound before plugging in the TRRS connector.

TRRS Pinout

Here are some pictures of cables professionally done by 9W2WHT..

Unsoldered connectors

Nicely heatshrink wrap connector

The final version look so professionally done cable by cutting the PTT handsfree cable..

Cut from the PTT

Special thanks to 9W2CEW, 9W2KHN and 9W2WHT for the testing on various handy.

73