DB9 Converter Adapter FT232BM/BL USB to Serial RS232/UART TTL/RS485 FTDI Module

The design uses Future Technology Devices Intl Ltd's (FTDI)FT232BM/BL chip. The FTDI website provides the USB drivers for a virtual com port. USB to UART TTL converter. USB to RS485 converter. USB to RS232 converter.

eBay