Amazon.com: YWBL-WH Converter Module CP2104 USB 2.0 to TTL UART 6PIN Module Serial Converter Board Module with Wire Support OS Windows 98/2000/XP/7/8/10 MAC OS-9 X-Windows CE Linux 2.40 or Higher Version, Module :
Problems communicating with CP2104 on custom PCB
Silicon Labs CP2104 USB to UART Driver | Device Drivers
5Pcs RobotDyn® CP2104 USB-TTL UART Serial Adapter Microcontroller 5V/3.3V Module Digital I/O USB-A