Using analog tech in the last device is the only way you can make it work with Jio. Jio won't give you the SIP settings obviously, so you can't use a true IP/VoIP phone. You can connect any phone's FXS port to the FXO port on the Jio modem/router. That's all..
Or use the JioCall app on a smartphone.
Those are your only options.
Or use the JioCall app on a smartphone.
Those are your only options.