This is an integration component for Home Assistant to allow a Rotel amplifier be controlled by Home Assistant using it's RS232 interface. It will let you turn it on and off, adjust the volume and change source.
I use this together with my Rotel RA-12 amplifier and Home Assistant 0.103.5
This is by now a quite old version of HA and I can't say whether it works with newer versions of Home Assistant.
Add the integration component package to your Home Assistant custom_components directory.
To configure, I added a configuration like below in configuration.yaml
Adjust to correspond with your RS232 device:
media_player:
- platform: rotelserial
name: ROTEL
serial_port: /dev/ttyUSB0