It is a device capturing and controling all the signals, which are being created by the whole system, especially the made and received phone call signals. The device is mostly used for connecting regular phone system with the Internet and backwards.
Voice over Internet Protocol (VoIP) calling is most convenient when using a mobile phone. BlackBerry users have plenty of choices when it comes to picking a VoIP app that is compatible with their phones so that they can take the convenience of VoIP calling with them anywhere.