iOS 7 beta: FaceTime Audio brings built-in VoIP, free long distance calling to iPhone

Initiating end of a FaceTime Audio call.

Glossed over by some amid the deluge of iOS 7 functions presente at WWDC on Monday, FaceTime Audio could be a game-changing addition to Apple's mobile operating system, even more so than the video calling service it's built on.

In the iOS 7 beta, FaceTime Audio can be found wherever the usual video version of the service is implemented. For example, users can place calls from the Phone app, the dedicated FaceTime app and Messages, among others. For now, the service appears is Wi-Fi only, though that could change before the OS is released this fall.

When FaceTime appears as a communication option, it is now followed by two icons: a camera for video and a phone for audio-only. In its current form, the two icons are situated very close to each other, forcing more precision than should be required to hit just one button. Alternatively, a video call can be made by selecting the "FaceTime" text, which appears to be the feature's default mode.

Using FaceTime from other apps like Messages is a bit different. As seen below, selecting the "Contact" asset to the right of a friend's name brings up FaceTime as one of three choices. From there, a pop-up pane is displayed with distinct options to make either a video or audio call.

The familiar FaceTime ring is used when placing a call, and sound quality is surprisingly good for what is essentially a beta product. Voice clarity is on a par with other apps like Skype for iOS, though using the iPhone's speaker causes considerable echo in this early version. It is unknown if FaceTime Audio supports full-duplex communication, that is the simultaneous transfer of voice data as seen in landlines, though lag was imperceptible in most situations.

Theoretically, because FaceTime is an Internet-based protocol, any two people with devices running iOS 7 can connect with one another, no matter where they are located. This is presuming they both have access to a Wi-Fi network.

Because the iPhone is used by so many, a baked-in VoIP solution that is readily accessible and easy to use could face opponents in the wireless industry as the data-based service could disrupt long-distance calling revenue streams. Just as telecoms were wary of allowing video FaceTime calls on their networks, which used valuable bandwidth, the audio-only version also proves problematic as data would eat into subscription minutes.

The new feature may not bode well for cellular carriers, such as AT&T, which fought to block certain subscribers from using the service on its network. AT&T has since promised that all customers, including those with grandfathered-in unlimited plans, will be able to use the video version of FaceTime over their networks, it remains unclear if the same policy will be extended to FaceTime Audio.