Idle insertion for physical layer rate adaption and time-division duplexing

A method is performed in a communication device that includes one or more media access control (MAC) entities, a coax physical layer (PHY), and a media-independent interface coupling the one or more MAC entities with the coax PHY. In the method, a bitstream is generated that includes data frames and characters corresponding to time windows in which the coax PHY does not transmit signals. The bitstream is provided to the coax PHY through the media-independent interface. Signals corresponding to the data frames are transmitted from the coax PHY during a transmit mode. The coax PHY enters a receive mode when the bitstream contains the characters corresponding to the time windows.