Improved modem terminals spaced along a high-frequency triaxial data line a long length. Each modem employs signal delay and differential detection circuitry to detect signals on the line which may have been degraded in transmission. Conversion circuitry and input-output circuitry interface the data...http://www.google.de/patents/US4156106?utm_source=gb-gplus-sharePatent US4156106 - Multiplex-data bus modulator/demodulator
