FTDI USB-COM-PLUS single- and multi-port serial communication modules provide a simple solution to the problem of connecting multiple RS232, RS422, or RS485 to USB. The FTDI USB-COM-PLUS single-port modules operate over a USB 2.0 Full Speed (12 Mb/s) interface, while the dual- and quad-port products operate over a USB 2.0 Hi-Speed (480 Mb/s) interface. These FTDI single-port and multi-port serial modules are powered from the USB port, require no external power adapter, and include PCB-mounted LEDs that indicate USB enumeration, RxD, and TxD signals. The USB-COM-PLUS modules handle the complete USB protocol and all level shifting without the need for any application software modifications.