As you can see, even among Chinese radios using RJ-45, the pinout varies. The KT-8900’s configuration (with Pin 3 as TXD and Pin 6 as RXD) is unique to the QYT KT-8900, KT-8900D, and KT-UV980. Do not assume compatibility with any other radio. Pre-Made Cables vs. DIY: What to Know If you buy a pre-made programming cable for the QYT KT-8900 (often labeled "QYT KT-8900 programming cable USB"), it will have a USB-A male end and an RJ-45 male end. Inside the USB plug, there is a tiny USB-to-TTL converter (usually a CH340G). The pinout at the RJ-45 end will match the table above.
| Radio Model | Microphone Pinout | Programming Pins | | :---: | :---: | :---: | | Baofeng UV-5R (Kenwood style) | 2.5mm + 3.5mm jacks | Tip/Ring/Sleeve (different) | | QYT KT-8900 | RJ-45 (8P8C) | | | TYT TH-9800 | RJ-45 | Pins 2 (TXD), 5 (GND), 3 (RXD) |
Here is the definitive pinout for the (the "top" connector):
For the best results, use a CP2102-based USB-to-TTL adapter, keep your ground connection short and direct, and always test with CHIRP’s "Read from Radio" function before attempting a write. With the correct "top pinout" wiring, the QYT KT-8900 is a breeze to program, unlocking its full potential as an affordable, high-performance mini mobile rig. The pinout remains identical. If you encounter issues, check the firmware version in CHIRP and ensure you are using the latest daily build. 73 and good luck!
