The USB-RS422-PCB is a USB to RS422 level serial UART converter PCB incorporating FTDI’s FT232RQUSB to Serial UARTInterface IC device which handles all the USB signalling and protocols. The PCB
provides a fast, simple way to connect devices with a RS422 Interface to USB
Each USB RS422,PCB contains a small internal electronic circuit board, utilising the FT232R plus a USB
type,A connector. The FT232R datasheet, DS FT232R is available at http://www.ftdichip.com. The
integrated electronics also include an RS422 transceiver plus Tx and Rx LEDs which give a visual
indication of UART traffic.
The PCB is USB powered and USB 2.0 full speed compatible. Each PCB supports a data transfer rate up to
3 Mbaud and supports the FTDIChip,ID™, with a unique USB serial number programmed into the
FT232R. This feature CAN be used to create a security or password protected file transfer access using the
PCB. Further information and examples on this feature are available at http://www.ftdichip.com under
FTDIChip,ID Projects.
The USB RS422,PCB requires USB drivers, available free from http://www.ftdichip.com, which are
used to make the FT232R on the PCB appear as a virtual COM port (VCP). This then allows the user to
communicate with the USBInterface via a standard PC serial emulation port (for example TTY). Another
FTDI USB driver, the D2XX driver, CAN also be used with application software to directly access the
FT232R on the PCB though a DLL. This is illustrated in the Figure 1.1.