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.

** PROBLEM RESOLVED **

For those that may search for a similar topic in the future, I'm posting my resolution here.

On the AVR-3805, all Zone 3 source selections must be performed by calling the Zone 1 commands. This seems very counter intuitive as Zone 1 would normally be thought of as being the "Main Zone".

As example, below are the commands to choose the SAT input for each of the available zones.
Main Zone = SISAT\r
Zone 2 = Z2SAT\r
Zone 3 = Z1SAT\r

Note that this is corrected with the AVR-3806 and newer models and all zone 3 commands are sent using the Z3 command (as would be expected).