Patent ID: 6940918

Claim:
A network transmitter generating data frames of data for transmission on a network medium, the transmitter including a frame generation circuit comprising: a) a first physical layer circuit generating data frames including overhead bits and data bits and modulating such frames of data for transmission on a network medium using a first modulation scheme; b) a second physical layer circuit generating data frames including overhead bits and data bits received from the media access layer circuit and modulating such frames of data for transmission on a network medium using a second modulation scheme; and c) the first physical layer circuit and the second physical layer circuit being operatively coupled for generating a compatibility mode frame, by the second physical layer circuit, comprising the initial header overhead bits modulated using the first modulation scheme and the remainder of the frame modulated using the second modulation scheme; wherein: the first modulation scheme is a pulse position modulation scheme and the second physical layer circuit obtains pulse position data from the first physical layer circuit for the initial header overhead bits, and the second modulation scheme is a quadrature amplitude modulation scheme and the second physical layer circuit generates pulses of a quadrature amplitude modulated carrier at times corresponding to the pulse position data to generate the initial header overhead bits.