Patent ID: 7636429
Filing Date: 2009-12-22
Classification: H04L,H04M

Abstract:
1. A Voice over Internet Protocol (VoIP) terminal comprising: a line interface unit adapted to interface a line connected to a telephone terminal; an audio processing unit adapted to convert and process a signal switched between the telephone terminal connected through the line interface unit and a VoIP network; a mode setting unit adapted to provide a request signal transmitted from the telephone terminal, a mode change signal in accordance with a communication state of a line connected to a Public Switched Telephone Network (PSTN), and a dial control signal to generate a communication request signal in accordance with the type of request signal; a PSTN circuit unit adapted to provide a communication termination sensing signal in accordance with the communication state of the line connected to the PSTN, to generate the communication request signal in accordance with the dial control signal from the mode setting unit and to transmit the request signal to the PSTN; a first switching unit adapted to connect the audio processing unit to one of the line interface unit and the PSTN circuit unit in accordance with the mode change signal from the mode setting unit; and in accordance with the mode change signal from the mode setting units a second switching unit adapted to connect the line connected to the telephone terminal to one of the line interface unit and the PSTN, wherein the VoIP terminal while connected to the VoIP network is automatically provided with a PSTN backup function in which an on the hook state of the telephone terminal is deferred for a predetermined time period even when the on the hook state is required to be performed while a user is engaged in communications, wherein a ring tone signal transmitted from a PSTN can be detected even when the telephone terminal connected to the VoIP terminal is in a VoIP mode state and simultaneously, the telephone terminal connected to the VoIP terminal senses the hook state of the telephone terminal while in communication with the PSTN, and can be automatically connected to the VoIP network upon the VoIP terminal being placed on a hook.