Abstract: A system for converting digital data to sine waves of differing frequency for networking computers. The sine waves are synthesized using variable encoding. The data is shifted through registers at a multiple of the data rate with the state of the stages of the register monitored to locate the zero-crossing of the sine wave. The state of the register stages is supplied to a series of multiplexers and resistors to generate the segments used to synthesize the sine waves. The data is monitored to derive a signal supplied to the multiplexers to determine the encoding pattern for each bit cell of data.