+ AA6YQ comments below
I must be missing something. Baud rate matches up but still nothing.
Changed the settings in the radio as well to match (although parity is NOT defined anywhere that I can see).
I guess I will have to come back to this later and spend more time. There must be that 'magic checkbox easter egg' somewhere that I an not seeing.
+ There is no "magic easter egg checkbox. All configuration items are documented.
+ Things to check:
1. that you've configured Commander's "Primary CAT Port" panel to control the correct virtual COM port created by your FT-991 device driver
2. that the USB cable you're using to connect the radio to your computer is "good", and properly seated at both ends.
3. try increasing the "CAT TOT" menu setting (32) to 1000.
4. the "CAT RTS" menu item (33) defaults to ENABLE. In typical Yaesu style, the meaning of this setting is not documented; try setting it to DISABLE.
+ Your earlier report that connecting your radio to your computer did not produce the expected notification from Windows is not a good sign. When you connect your radio to your computer, the Window Device Manager should show two new COM ports appearing. Trouble in this area requires engaging with Yaesu support.
+ Ed WA6WGS, how are menu items 32 and 33 configured on your FT-991?