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.
Network router transformed, from the device used only for connection between different networks, into a device capable of performing many additional functions. More and more customers of Cisco deploy routers with integrated network services – complex network routers, which transmit voice, video and data, ensure the Internet connection and provide Wi-Fi and other add-ons.