Patent ID: 6934326

Claim:
A communication apparatus selectively connectable to a central communication apparatus to perform a full duplex communication utilizing a Digital Subscriber Line (xDSL) modem, the communication apparatus comprising: a communicator that executes: a first transmission mode to transmit a plurality of Mode Select (MS) signals designating a particular communication mode to the central communication apparatus, the central communication responding to the transmitted MS signals by issuing one of a plurality of acknowledge (ACK) signals and a plurality of negative acknowledge (NAK) signals; and a second transmission mode to transmit a plurality of Mode Request (MR) signals to the central communication apparatus requesting a transmission of MS signals from the central communication apparatus, said commununicator receiving said MS signals issued by the central communication apparatus and responding by transmitting one of said ACK signals and said NAK signals to the central communication apparatus; and a controller that executes one of said first transmission mode and said second transmission mode upon initialing a communication with the central communication apparatus, wherein a first group of frequencies utilized by signals transmitted from the communication apparatus and a second group of frequencies utilized by signals received by the communication apparatus belong to a mutually different band, said plurality of MS signals carrying identical data with identical timing, but having different carrier frequencies, said MR signals carrying identical data with identical timing, but having different carrier frequencies.