Apparatus and method for communicating voice and data between a customer premises and a central office

A modem for communicating data over a subscriber loop, comprising:

• means for sensing an indication that POTS is or is not operable to transmit signals in a POTS frequency band;
• means for transmitting data in a full-band transmission state in response to the indication that POTS is not operable to transmit, where the full-band transmission state is defined by data transmission in a frequency band including frequencies above and below approximately 4000 Hertz;
• and
• means for transmitting data in a band-limited transmission state in response to the indication that POTS is operable to transmit, where the band-limited state is defined by data transmission in a frequency band of frequencies above approximately 4000 Hertz.

A method for communicating data over a subscriber loop, the method comprising the steps of:

• sensing an indication that POTS is or is not operable to transmit signals in a POTS frequency band;
• transmitting data in a full-band transmission state in response to the indication that POTS is not operable to transmit, where the full-band transmission state is defined by data transmission in a frequency band including frequencies above and below approximately 4000 Hertz;
• sensing an indication of simultaneous transmission of signals on the subscriber loop on a POTS frequency band in response to the indication that POTS is not operable to transmit;
• transmitting data in a band-limited transmission state in response to the indication of simultaneous transmission of signals on a POTS frequency band, where the band-limited state is defined by data transmission in a frequency band of frequencies above approximately 4000 Hertz;
• and
• transmitting data in the full-band transmission state in response to a lack of indication of simultaneous transmission of signals on a POTS frequency band.