Making phone calls to non-apple users
Using my new IPad (wifi+cellular) how can I make phone calls other than by using Face Time, which I understand can only call people also using Apple devices? There still are a few million people out there who are not yet Apple users! Apps like Skype of course need an Internet connection. I have bought a global roaming SIM card, but need an app that can dial international numbers though a normal carrier.
iPad Air Wi-Fi, Cellular, iOS 7