| 主权项 |
1. A Voice over Internet Protocol (VoIP) gateway device comprising:
a connector which connects to a first terminal; a communication unit which communicates with a proxy server that relays a VoIP communication between the first terminal and a second terminal; a controller which transmits, to the proxy server, an invite message for connecting a call, corresponding to a call back function, to the second terminal in response to a request from the first terminal for the call back function; and a storage unit which stores a ringtone specifically corresponding to a call received by the call back function, wherein the call back function is a function by which one or more repeated attempts at a predetermined interval while the second terminal is busy to connect a call from the first terminal to the second terminal are automatically made after an initial attempt to initially connect the call from the first terminal to the second terminal fails, wherein the controller transmits the stored ringtone to the first terminal in response to receiving, from the proxy server, a ringing message corresponding to the invite message, and wherein the controller does not transmit any message to the first terminal in response to receiving, from the proxy server, a busy message in response to the invite message, after the predetermined interval. |
