14 DAY TRIAL // The new features in iOS 8 cannot come soon enough to OS X Yosemite. One of the awesome new ones is Continuity and it works great between iDevices.
Just imagine someone calls you on your iPhone, but the device is charging in another room. You can now take that call on your iPad or your old iPhone that doesn't even have a SIM card in it. It all works via WiFi because of iOS Continuity.
Simple setup
Apple made this one of the great features in iOS 8 and sure enough it is pretty awesome to use a device that doesn't even have a SIM card to see who's calling you, to answer that phone call and even send or receive text messages. And we are not talking about iMessages, but just the plain-old text messages you exchange with anyone, including non-iOS users.
Continuity should be enabled by default. If not, the setup or troubleshooting is fairly easy to do it. Just go into the Settings app and select FaceTime. Make sure the option to have iPhone Cellular Calls is ON. After that just go ahead and disable FaceTime by pressing the button on top and then putting it on. Depending on your carrier, this can take up to a minute.
Make sure you follow the same steps on your iPad and you are good to go.
It works on any device
We have tested that with an iPad mini and it works flawlessly. However, the neat trick is to use it with another iPhone. Let's just say you have your old iDevice laying around the house. Did you know you can use it even without a SIM card inside it? All you have to do is keep that ON and connected to the same Wireless Network.
The trick is that you have to be signed into the same iCloud account. If you follow these steps, then you can take calls on your iPad or old iPhone. Furthermore, you can initiate calls from other devices just by opening the Contacts app and taping on a Phone number.
You will see that the sound is automatically directed through the iPad speakers, unless you have a headset with a built-in mic connected to the device. Obviously, this will not work if your iPhone has no battery left in it or if it is not connected to the same WiFi network.
Apple will include the same functionality on compatible Macs so you can use the microphone and speakers of your computer to call and be called.