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.
A Media Gateway Control Protocol (MGCP) is a Voice over Internet Protocol system used to handle the exchange of information and the management of a multimedia conference session. The exchange of information, known as signaling, is responsible for connecting, controlling and terminating sessions. Therefore, an MGCP protocol is used to set up, maintain and end calls between multiple points.