The QYT KT-8900 Go to product viewer dialog for this item. uses a 3.5mm jack for programming, typically located at the rear of the radio labeled as DATA. While the port can accept a 4-contact (TRRS) plug, only three connections are required for programming, allowing the use of a standard 3.5mm stereo (TRS) plug. 3.5mm Programming Jack Pinout
For a standard USB-to-TTL (UART) interface (such as CP2102 or FTDI), the connections are as follows: Tip: RX (Data from Radio to PC) Ring: TX (Data from PC to Radio) Sleeve: GND (Ground) Front Panel RJ45 Connector Pinout
The front microphone port is an RJ45 connector and is primarily for the hand mic, but it also contains data pins. 1 Data Input 2 3 4 MIC Ground 5 6 GND (Ground) 7 +8V DC Out 8 Null / DATA Programming Important Cable Notes
Voltage Levels: Programming requires TTL levels (3.3V or 5V); do not connect a direct RS-232 serial cable as it can damage the radio.
Compatibility: If building a cable, a CP2102 or CH340 based USB-to-TTL module is recommended for modern operating systems like Windows 10/11.
Connector Fit: Some 3.5mm connectors may be too thick to fully seat in the recessed rear jack; a slim-profile connector is often necessary.
The QYT KT-8900 uses a 3.5mm TRRS (4-pole) or TRS (3-pole) jack for programming, located on the rear panel. Unlike many other mobile radios that use an RJ45 mic port for data, the KT-8900 utilizes a standard audio-style connector for its serial interface. Programming Cable Pinout (3.5mm Jack)
The radio's programming interface operates on a 3.3V TTL level. To build a DIY cable, you can use a common USB-to-TTL module (like a CP2102 or FTDI Friend) and wire it to a 3.5mm plug as follows: 3.5mm Plug Section Connection to USB-TTL Module Tip RX (Radio Data In) TX Pin on Module Ring 1 (Middle) TX (Radio Data Out) RX Pin on Module Sleeve (Base) GND (Ground) GND Pin on Module qyt kt8900 programming cable pinout top
Note: While the jack is technically TRRS, a standard 3.5mm Stereo (TRS) plug is sufficient as only the first three connections are used for data. Hardware Requirements
USB-to-TTL Adapter: It is highly recommended to use a module with an FTDI or CP2102 chipset. Prolific chips (PL2303) found in many cheap cables often face driver compatibility issues on Windows 10/11.
Slim Connector: The programming jack on the back of the KT-8900 is often recessed into the case. Standard bulky 3.5mm plugs may not fit; use a "slim" style connector or a repurposed PC speaker cable for a better fit. Software Setup
Drivers: Install the appropriate drivers for your specific USB-TTL chipset before plugging in the cable.
Software: The radio is compatible with the official QYT KT-8900 software or the community-standard CHIRP.
COM Port: Once connected, check your Device Manager to identify the assigned COM port. In the software, ensure you select a port higher than COM2 (often COM3 or above) to avoid communication errors. Recommended Retailers
For those who prefer a pre-made solution, reliable cables are available from: The QYT KT-8900 Go to product viewer dialog for this item
RT Systems: Known for high-quality FTDI cables and dedicated programming software.
Miklor: A leading resource for Chinese radio information and verified cable links. Passion Radio: Supplies original factory-direct QYT cables.
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.
The KT-8900 follows a non-standard (but common among Chinese mobile radios) serial TTL logic. Important: This is NOT a standard RS-232 cable. It uses TTL levels (0-5V), so a simple USB-to-serial adapter with a MAX232 chip will NOT work. You need a USB-to-TTL adapter (e.g., using a CP2102, CH340, or FTDI chip).
Here is the definitive pinout for the RJ-45 connector that plugs into the radio’s front panel "MIC" port (the "top" connector):
| Pin Number | Signal Name | Wire Color (Typical in OEM Cable) | Function | | :---: | :---: | :---: | :---: | | Pin 1 | NC / GND | Black | Not connected in programming mode (ground on some versions) | | Pin 2 | SPK- (Speaker -) | Yellow | Negative speaker line (not used for programming) | | Pin 3 | MIC / TXD | Blue | Programming Transmit Data (Radio → PC) | | Pin 4 | PTT | Green | Not used during programming | | Pin 5 | GND | Brown | System Ground (critical for programming) | | Pin 6 | RXD | Red | Programming Receive Data (PC → Radio) | | Pin 7 | VCC / 5V | Orange | +5V power from radio (only active when radio is ON) | | Pin 8 | SPK+ (Speaker +) | White | Positive speaker line (not used for programming) |
Before we dive into the pinout, a word of caution. Many operators assume the QYT KT-8900 uses the same standard Kenwood-style K1 connector found on Baofeng UV-5Rs or Quansheng radios. The Official QYT KT-8900 Programming Cable Pinout (Radio
It does not.
While the connector looks similar, the QYT KT-8900 often utilizes a slightly different interface or requires a specific variant of the programming cable. Using the wrong cable or forcing a connector can damage the radio’s port.
If you’re a DIY ham, building a cable is straightforward and saves $15-$20. Here’s the component list:
If you are a DIY enthusiast and want to solder your own interface, remember that the pinout on the radio side is standard 3.5mm TRRS, but the pinout on the USB side depends entirely on your USB-to-TTL adapter board.
Crossing these wires is the fastest way to frustrate yourself, so double-check with a multimeter continuity test before plugging it in.
Even with the perfect physical connection, your software must match. In CHIRP:
In the official KT8900.exe software (only runs on Windows XP/7 32-bit):