I’m looking for info if the Rotel S14 is supported by the existing Rotel binding. There is no protocol documentation available on the manufacturer webpage.
You provide the answer to your question 
Lack of documentation doesn’t mean there is no control 
I also asked the Rotel directly - they wrote back there is no network control. If this is correct - how the unit is controlled? Wifi only?
Anyway - looks like there is currently no easy way to get it controlled by openHAB
Maybe they just did not implement any remote control for this device.
There is android app, ios app, the device is “roon” ready (some apple stuff?). There has to be some remote control, over wifi or bluettoth or over a cloud connection. There is chromecast built in.
I´m sure there is a way of getting in on openHAB, but most likely it would involve reverse engineering of the protocol. Rotel is a small company, so I’d bet they extended the existing protocol.
If I don´t find anything better I might get it anyway, but I have MHI aircon binding waiting to be developed…
Edit: It´s there but not documented
" Rotel Control App: The Rotel Control app (for Apple iOS and Android OS) turns your compatible smartphone or tablet device into a wireless remote control for the S14 integrated amplifier. The Rotel Control app offers an intuitive user interface with seamless access to thousands of Internet Radio Stations, plus streaming of your favorite high-quality music files from [Tidaland [Qobuz]. The app also provides transport control of your music stored on a USB thumbdrive with ease."
Edit2: Looks like chromecast binding could to the most of the control. If this is right a simple on/off and source switching would cover most of the S14 features.