Patent ID: 6952442

Claim:
A communication apparatus utilizing a Digital Subscriber Line (xDSL) modem that is selectively connected to a central communication apparatus to perform a full duplex communication, comprising: a communicator that transmits a plurality of Mode Request (MR) signals to the central communication apparatus, said plurality of MR signals requesting that the central communication apparatus respond by transmitting a plurality of Mode Select (MS) signals to the communication apparatus, said plurality of MS signals designating a particular communication mode; said communicator transmitting one of acknowledge (ACK) signals and negative acknowledge (NAK) signals to the central communication apparatus when said plurality of MS signals are received by the communication apparatus, wherein first frequencies utilized by said plurality of MR signals and second frequencies utilized by said plurality of MS signals belong to a mutually different band, said plurality of MR signals carrying identical data with an identical timing, but having different carrier frequencies.