Patent ID: RE39165

Claim:
A method for transmitting data in a pulse code modulation (PCM) modem system, said method comprising the steps of: initializing a training mode characterized by a training interval; adjusting spectral shaping in a transmit modem during at least a portion of said training interval to thereby reduce color in the spectrum of transmit signals, relative to signals transmitted by said transmit modem during a normal data mode, wherein said adjusting step comprises the step of decreasing the number of redundancy bits associated with said a line coder; transmitting a predetermined training sequence from said transmit modem during said training interval; readjusting spectral shaping in said transmit modem to thereby increase color in the spectrum of signals transmitted after said training interval, relative to signals transmitted by said transmit modem during said training interval, wherein said readjusting step comprises the step of increasing the number of redundancy bits associated with said line coder; and transmitting data symbols in accordance with a PCM protocol.