Digium Ringtones for different line keys

On the surface, it sounds correct, but I wouldn’t know for sure without looking at all of your configuration files.

Make an alert, add the alert to the phone, figure out how to get the alert-info string called with a Dial (I can’t help with this), profit. That’s the process.

Does your res_digium_phone_devices.conf file show the alert that you made added to the type=phone?