CAN Filter is used to correct the data stream which is transferred from one device connected to the CAN bus to another. It is connected into the gap betwen the devices and allows either not to let the selected messages pass or transfer them changing the data. It works in both directiions simultaneously. Programming is performed using a special software. The filter is set up via the USB port. When setting up the CAN filter connected to the vehicle, there is a protection diode preventing the USB port damage. There is also a possibility to set up the already installed filter via CAN bus.
