How would you configure this CEC device?

Here are the results of my scan:

device #5: Audio
address:       f.f.f.f
active source: no
vendor:        Onkyo
osd string:    HT-R393
CEC version:   1.4
power status:  on
language:      ???
currently active source: unknown (-1)

Whenever I usually see a CEC scan result, and the example at https://www.home-assistant.io/components/hdmi_cec/ has this as well, the address of the main component is something like 5.0.0.0. To activate subcomponents, you’d turn on 5.0.0.0, 5.1.0.0, 5.2.0.0, etc. But this address is the highest possible hex value, and this is an audio receiver with many inputs.

Any idea what may be happening here? Or do I just have a device that can’t be controlled via CEC? It definitely has some support, since I had to enable it via the settings menu.

Thanks.