Data is transferred using frequency shift keying modulation in a frequency
range that is not within a television signal frequency range used to
conduct the television signal over the transmission line. Consequently,
the present invention may allow the television signal and the data to be
conducted on the same cabling. The frequency shift keying modulation is
provided by generating a modulated data signal based on information
included in the data. For example, the frequency shift keying modulation
generates a modulated data signal at a first frequency when the data is
equal to a logical 0 and at a second frequency when the data is equal to a
logical 1.