when call is picked up on land line, you have to wait for for app to ring on cell phone or it will start ringing after you pick up the land line. Also sometimes after I have finished the call on the land line the app will ring and no one is there. some times the app doesn't even ring. also need to add more options to scheduling in silent mode so you can have it in silent mode on your days off without always having to go into the app and set to away. garbage app would rare it a Zero