The AK-USB-RS485-FD is a USB to RS485/422 converter that has Full Duplex capabilities. Usually the RS485/422 protocol allows a single node of the network to either send or receive data, but not both at the same time. The AK-USB-RS485-FD board has two “channels”: one for receiving data and the other for transmitting data, achieving full duplex communication able to emulate a traditional “serial port”.

The board is based on a genuine FTDI FT232RL chip and the RS485/422 channel is seen on the host as a virtual serial port.

The board comes in two versions: with screw terminals and without screw terminals to directly solder wires to the board (or to use another kind of connector). There is a drop menu up here to choose any of both options.

On the back of the board there is a solder jumper to enable/disable the 120 Ohm termination resistor independently on the “TX” and “RX” channels. The resistor it’s disabled by default but you can enable it by joining the jumper with some solder. On the top of the board there are two LEDs that blink when data is sent or received.

The board has a mini USB connector and it’s powered directly using the 5V from the USB bus.

Looking for a traditional, half-duplex, USB-to-RS485/422 converter? We ship that too.


  • Full Duplex RS485/RS422
  • USB high speed
  • Based on the FTDI FT232RL chip
  • Modbus compatible
  • 3Mbps max. data rate
  • Up to 32 transceivers in RS485 mode
  • Up to 32 transceivers in RS422 mode
  • Selectable 120 ohm load resistor
  • Optional screw terminals
  • Libraries and drivers for Windows and Linux, by FTDI




Additional information

Weight N/A
Dimensions N/A
Screw Terminals

Without Screw Terminals, With Screw Terminals



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AK-USB-RS485-FD – USB to RS485/422 converter (Full Duplex)

A board that converts USB into RS485/422, with Full-Duplex capabilities.


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