1. A method for multiple users to communicate using a common communications channel, comprising the steps of: generating coded application bits for a plurality of applications; assigning a plurality of tones to the coded application bits for each application; encoding the coded application bits for each application into multitone symbols at a transmitter using the plurality of tones assigned to the respective coded application bits; transforming the multitone symbols into complex time-domain samples using an inverse discrete Fourier transform; and transmitting the complex time-domain samples transformed from the multitone symbols for each application on a common channel using a discrete multitone modem.