I want to integrate RingCentral into my app to make phone calls to the customers. Let's say there is a button `Call` for every customer on my website and if I click this button a new RingOut will be created through API (this endpoint). So my question is what happens after that, if I use my phone and have RingCentral app installed on it? For the moment I can't test it myself, because I can't have my sandbox account on my phone. Will there be a notification on my phone that the call is happening? Or will I have to switch to RingCentral app to see the call there? Also, can you use RingOut without RingCentral app, but with using default phone system?