Now you can make calls to anyone in India and outside using the Facebook Messenger on Android and iOS. You can make calls only to Facebook Messenger users on iPhone and Android over 3G or WiFi. It is not available for Facebook Messenger for Windows Phone that was launched recently. You can even call from Chatheads and also use speaker phone. It even asks you to rate the call quality after you finish the call. The call quality is good if you have good network or WiFi connectivity.
Source : AndroidOS
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