I bought a special rj45 to bt socket cable to allow me to do this. I think all modems nowadays are pretty much voice modems arent they? Tbh im not sure. I thought i would ensure the phone still works before i try any of the answering machine programs and i keep getting a busy tone when i try ringing my home from my mobile with it connected as described.
Dell XPS 13 9370 (2018) review