Patent ID: 7734301
Filing Date: 2010-06-08
Classification: H04M

Abstract:
1. A communication system comprising: a main device capable of communicating with a destination station through a line; and at least one subsidiary device connectable to said main device, said subsidiary device including a connection request signal transmitting system that transmits a connection requesting signal requesting to perform a communication through the line to said main device, said main device including a status signal transmitting system that transmits a status signal indicative of an operational status of said main device to said subsidiary device in response to the connection requesting signal transmitted from said subsidiary device, wherein said subsidiary device performs different operations in accordance with the status signal transmitted from said main device, said subsidiary device transmits a line release requesting signal requesting the main device to automatically release the line, when a communication to be performed by said subsidiary device satisfies a predetermined condition and said subsidiary device receives the status signal indicating that the main device is using the line.