Arduino USB-to-Serial Tutorial - Programming the Pro Mini - YouTube
Stand-alone Arduino
3 Ways to Use Arduino as USB Serial Adapter Converter - Oscar Liang
Ways to Use Arduino as USB to TTL Converter - Hackster.io
Arduino Uno as USB to Serial converter (bypass 328p) - Arduino Stack Exchange
3 Ways to Use Arduino as USB Serial Adapter Converter - Oscar Liang
Using Arduino as USB to TTL converter - YouTube
How to use an Arduino as a USB to TTL converter || Arduino tutorial - YouTube
Arduino USB 2 Serial Micro | Arduino Documentation
Serial cable adapter RS232 TTL 4 pin to USB for Arduino PL2303HX - Cablematic
20pcs CP2102 USB to TTL Serial Adapter Module USB to UART Converter Debugger Programmer for Pro Mini OPEN-SMART for Arduino - products that work with official for Arduino boards
Arduino USB 2 Serial Micro - Corzotech
USB TO SERIAL CONVERTER BOARD A000107 Arduino製|電子部品・半導体通販のマルツ