Here’s a clear and detailed write-up about the QYT KT8900 programming cable pinout, focusing on the "top" (radio side) connection, since that’s where most confusion arises.
If you have the pinout correct (or bought a supposedly compatible cable) and the radio is still refusing to write or read, check these three critical points:
If you own a QYT KT-8900 mini mobile radio, you know it’s a powerhouse for its size. But programming it manually via the front panel? That’s a fast track to frustration.
To program this radio efficiently with CHIRP or the official QYT software, you need a USB programming cable (often a FTDI or Prolific-based cable) .
But here’s where 90% of the confusion happens: The pinout on the “top” connector (the radio’s RJ-45 port). qyt kt8900 programming cable pinout top
Let’s break it down so you can build your own cable, fix a broken one, or simply understand what’s happening inside that plastic housing.
When we say “top pinout,” we mean looking at the metal contacts of the plug with the clip facing down (away from you) or the latch facing up depending on your reference.
Here is the standard, working pinout for the QYT KT-8900 (and most QYT/Kenwood clones like the KT-7900, KT-8900D, and BTECH UV-2501) :
| Pin # | Signal | Wire Color (typical in pre-made cables) | |-------|--------|------------------------------------------| | 1 | NC | (Not connected) | | 2 | +5V | Red | | 3 | GND | Black | | 4 | TX (Radio transmit → PC receive) | Green | | 5 | RX (PC transmit → Radio receive) | White | | 6 | GND | Black (sometimes bridged with pin 3) | | 7 | Audio out to radio (speaker) | Yellow | | 8 | PTT / Mic ground | Brown | Here’s a clear and detailed write-up about the
⚠️ Crucial Note: Pin 1 is on the left when the clip (latch) is facing up and you are looking at the contact pins of the plug.
Yes, if you wire a Bluetooth module (HC-05) to pins 1,2,3,6 using the TTL-level signals. The “top” pinout remains the same.
The accessory port on the KT-8900 is recessed. A standard audio cable might fit, but a programming cable often has a specific molding. Ensure the cable is inserted fully and firmly. Even a millimeter of gap can disconnect the data line (usually the Tip or first Ring).
When looking for the "top" pinout, we are referring to the orientation where the cable connector is inserted into the radio’s accessory port (speaker/mic jack) with the retaining screw facing away from you. Troubleshooting: "The Cable is Connected, But the Radio
Most programming cables for this radio are comprised of a USB-to-Serial adapter (often using the Prolific PL2303 or FTDI chipset) and a 3.5mm TRRS (Tip-Ring-Ring-Sleeve) or TRS style plug.
Here is the typical logic flow for the connector found on the QYT KT-8900 accessory port:
Note: On some KT-8900 variants, the specific function of the PTT and Data lines can be bridged internally within the cable. This is why "homemade" cables often fail—the radio expects a specific resistance or bridging configuration on the data lines to recognize a programming session versus a speaker-mic session.
In the QYT KT8900 pinout, Pin 2 is TX from the radio. That means it sends data to the PC. Therefore, it must connect to the RX pin on your USB adapter. Similarly, Pin 3 (RX on the radio) connects to TX on the adapter.
If you connect TX→TX and RX→RX, you will get nothing but timeouts.