Patent ID: 7586845

Claim:
A button telephone apparatus comprising: an IP trunk for simultaneously making voice communication and data transmission using the same communication line connected to an external IP network, and monitoring traffic of data-based packets in data communication; and a controller supplied with the result of monitoring from said IP trunk for increasing or decreasing the number of voice channels for making voice communication in accordance with a change in the traffic of data-based packets, wherein: said IP trunk comprises a router for relaying the data-based packets between an external data-based network for making data communication and the external IP network; said router measures the traffic of data-based packets in data communication for a given time; and said controller calculates a data communication rate currently used for data communication based on the traffic for the given time measured by said IP trunk, calculates the number of voice channels available for voice communication from the calculated data communication rate, the rate of the communication line, and a rate required for one channel of the communication line, and increases the number of enabled voice channels when the calculated number of available voice channels is larger than the number of currently enabled voice channels.