To disable the internal SunSpec transmitter, first ensure that the inverter is powered off - DC switch in OFF position and AC breaker also in OFF position.
Once the inverter wire box cover is off, remove the four nuts securing the AC cover plate with a 10mm socket.
With a T-20 screwdriver, remove the fastener securing the blue "RSD" wire. Use wire tape to cover the end of the blue wire so it does not come into contact with anything else. Then replace the cover plate and the four 10mm nuts.