Cable for BTECH UV-50x3

The transceiver manual shows MiniDin8 connector in the back with the pinout that doesn’t match any popular transceiver models:

This calls for a custom cable which can accommodate both audio and optionally CAT.

MiniDin8 Pin 1 (PKD) → 3.5mm TRRS audio Ring 1 (RIG_AFIN)
MiniDin8 Pin 2 (GND) → 3.5mm TRRS audio Sleeve (GND)
MiniDin8 Pin 3 (PKS) → 3.5mm TRRS audio Ring 2 (PTT)
MiniDin8 Pin 4 (RX9600) → 3.5mm TRRS audio Tip (RIG_AFOUT) - for 9600 baud operation or…
MiniDin8 Pin 5 (RX1200) → 3.5mm TRRS audio Tip (RIG_AFOUT) - for 1200 baud operation

MiniDin8 Pin 2 (GND) → 3.5mm TRRS serial Sleeve (GND)
MiniDin8 Pin 7 (TXD) → 3.5mm TRRS serial Ring 1 (RIG_TXD)
MiniDin8 Pin 8 (RXD) → 3.5mm TRRS serial Tip (RIG_RXD)

For serial CAT control Digirig heeds to be in RS-232 configuration.
If both connections are implemented on the Digirig side (again CAT is optional), then the cable would look something like Yaesu’s MiniDin10:

Off-the-shelve MiniDin8 cable can be a good starting point for a homebrew build.

Instruction Manual for UV-50x3

I was successful with this pin assignment and a home made cord. I was able to successfully connect to a local packet station and another VARA FM station a bit further away. The Digirig I am using though had pretty low sound levels. I did cut through the PC board for the ATT mark as it provided a better condition with my other patch cords going through the external speaker and mic port on the radio. I think I prefer the MiniDin8 cable and will have to clean it up a bit more…

1 Like

Well…not sure what happened but this morning I attempted to use the home brew cable and it’s not working. I can hear other stations sending digital data through VARA and I can receive, decode APRS packet information in Sound Modem but when I attempt to transmit a packet, the radio is not keying up.

I sent six emails last night via Winlink/VARA and afterwards, the radio was warm but not hot enough to kick on the external fan.

I spent some time double checking all of the cable connections this morning with a meter. Each pin on the MiniDin8 plug corresponds to the identified connection point on the TRRS rings. I did not find any pins or cross connections where something might be shorting out across the pins.

Will need to find some time to cut the cable back and possibly start over with a fresh build.

Try quick and dirty PTT troubleshooting method described here:

Well, turns out this likely wasn’t a cable issue or a pin/connection issue.

I reprogrammed my radio last night after updating some local repeaters. When the software updated, it turned off the “packet” option and did not set a dedicated band on the radio for transmitting. (sigh…)

This was completely user (albeit it, inexperienced) related.

1 Like