INTRODUCTION This USB to TTL converter combine the USB-232-1 (USB to Single RS232 Adapter) and TTL-232-1 (Port-powered RS232/TTL converter) allows you to convert USB to TTL/CMOS compatible levels and vice versa. - It can be used to set up APC220 RF wireless module. - It can be used as STC microcontroller program downloader. - The PCB color may vary and not the same as shown in the picture.