+ AA6YQ comments below
Thanks for the response. When I connect directly to the 7160's port (COM4) all works normally. When I'm connecting through Win4Icom (COM21), I can track frequency, change frequency and change mode via the Commander Main window. The only thing that doesn't seem to work is the spectrum waterfall. The window stays blank when it's connected to the emulated port.
+ That's because when Win4Icom is "in the connection path", Commander does not receive Spectrum-Waterfall data from your transceiver.
+ Win4Icom does not fully emulate the connected Icom transceiver. Besides the Spectrum-Waterfall CI-V commands, it also fails to convey the CI-V commands that query and report CW keying speed; there are likely other gaps.
+ If Commander is not directly connected to your transceiver, the first step in debugging any transceiver control problem is to directly connect Commander to your transceiver.