Abstract: A method and apparatus for transmitting parallel digital data bit patterns over a single line is disclosed. Parallel digital data bit patterns are transformed into analog signals that are representative of the digital data bit patterns. Each digital data bit pattern is assigned an analog representation (either frequency, phase, or amplitude depending on the transmission medium). Each analog representation of the digital signal is then combined with a carrier signal and transmitted to the receiving end of the apparatus where the carrier signal is stripped off and the original analog signal transmitted is transformed into the original parallel digital data bit pattern transmitted.