Apple Programming - FujiNetWIFI/fujinet-firmware GitHub Wiki
All commands to the Apple II FujiNet are issued via SmartPort.
In order to do so, you must first find the SmartPort card, and its dispatcher routine, and then you can issue a status command of $00 to get all devices. You can then iterate through them to find the device of an appropriate type (e.g. NETWORK or FUJI), and send commands to them.