) primarily uses a for data transfer. According to documentation from HamGuyParts , while the radio may feature a 4-contact (TRRS) jack, it typically only uses three pins for programming: Ground (GND) , Receive (RX) , and Transmit (TX) . QYT KT8900 Programming Pinout (3.5mm Plug)
Turn the radio . Ensure the volume is turned up to at least 50% (some radio firmware variations require this to open the data line). qyt kt8900 programming cable pinout top
Connects to the TXD pin of your USB-to-TTL serial adapter board. 2. The Ring (Pin 2) Function: Transmit Data (TXD) ) primarily uses a for data transfer