iOS Wi-Fi Calling
As of iPhone model 5c Apple has a very cool new feature they call Wi-Fi Calling. This feature allows you to make calls from an iPad or iPhone that has no telephone service but instead connects using Wi-Fi to another iPhone in your house to complete the actual call.
This allows you to move your iPhone anywhere in your house and well beyond the 10ft Bluetooth range limit. As long as you leave a semi-dedicated iPad or old iPhone next to the XLink then the XLink will connect to it via Bluetooth. As long as the main iPhone is in the house then the Xink will make and receive calls using it.
Note: This is a new feature and we expect apple to keep improving it. There are a couple of things that should be noted right now:
Normally the XLink will generate error tone if the cell phone is not available to make a call. When connected through a iOS Wifi link this feature does not work
It can take a few rings for the caller ID to come through