There are some USB "phones" - basically composite USB devices with audio and HID, where HID is used to handle keypad and display (if present). I'm using very ch

There are some USB "phones" - basically composite USB devices with audio and HID, where HID is used to handle keypad and display (if present). I'm using very cheap EX-03 "Skype" phone: https://tomeko.net/software/SIPclient/EX03.php https://tomeko.net/software/SIPclient/EX03.php but similar devices are also made by big brands, they are just more expensive (Polycom CX300, Plantronics Calisto, Yealink MP50 maybe?) and probably undocumented.