On May 2011, it was found that Face Time would work seamlessly over 3G on all i Phone, i Pad and i Pod Touch models that supported it.
Even though Face Time worked only over 3G at that time, it now supports 4G LTE calls on networks all over the world, availability being limited to operators' GSM plans.
Face Time works by connecting an i Phone 4 or later, a fourth generation i Pod Touch or later, an i Pad 2 or later, or a computer with mac OS, to another supported device.
Face Time is currently incompatible with non-Apple devices or any other video calling services.
A new audio-only version of Face Time, named Face Time Audio, was announced during the annual Apple Worldwide Developers Conference (WWDC) keynote speech on June 10, 2013, and released with i OS 7 on September 18, 2013.Cellular talk time/minutes are not used after switching from a voice call to a Face Time call.Face Time calls can be placed from supported devices to any phone number or email address that is registered to the Face Time service.The Face Time protocol is based on numerous open industry standards Upon the launch of the i Phone 4, Jobs stated that Apple would immediately start working with standards bodies to make the Face Time protocol an "open industry standard".While the protocols are open standards, Apple's Face Time service requires a client-side certificate.