I recently switched my Pronto TSU9600 programming from IR to serial for my Denon AVR-3805. All of the Zone 1 & 2 commands work just fine via serial, but I cannot control Zone 3 with serial at all. The serial protocol docs seem vague as to whether zone 3 is supported.

Can anyone confirm if Zone 3 can be controlled via serial? It seems incredibly dumb if it can't be. Also dumb is the fact that I can't have both hard-wired IR and serial connected to the amp at the same time. If Z3 can't be controlled via serial, then I have to choose to use one-way IR for all zones or use serial for Z1 & Z2 and no control of Z3.