Each USB-RS485 cable contains a small internal electronic circuit board, utilising the FT232R, which is
encapsulated into the USB connector end of the cable. The FT232R datasheet, DS_FT232R, is available at
http://www.ftdichip.com. The integrated electronics also include the RS485 transceiver plus Tx and Rx
LEDs which give a visual indication of traffic on the cable (if transparent USB connector specified).
The other end of the cable is bare, tinned wire ended connections by default, but can be customised
using different connectors to support various applications.
The USB-RS485 cable is designed for use at the end of an RS485 network up to approximately 10m. For
longer networks or placement of the USB-RS485 cable in the middle of an RS485 network it is
recommended that the attached wire is cut to 20cm or less to ensure signal integrity
Cables are FCC, CE, RoHS compliant.
The cable is USB powered and USB 2.0 full speed compatible. Each cable is 1.8m long and supports a
data transfer rate up to 3 Mbaud. Each cable 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 cable. Further information and examples on this feature are
available at http://www.ftdichip.com under FTDIChip-ID Projects.
The USB-RS485 cables require USB drivers, available free from http://www.ftdichip.com, which are
used to make the FT232R in the cable appear as a virtual COM port (VCP). This then allows the user to
communicate with the USB interface 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 cable though a DLL.