Data transmission system with modems coupled to a common communication medium.

摘要

A plurality of data processors (4a to 4n) are coupled by respective modems (5a to 5n) to a communication medium (1, 2) at points thereof. Transmission and reception of digital information signals among the modems are effected through a headend (3) located at a predetermined point on the communication medium. A pilot signal generator (6) is provided which sends out a pilot signal having a predetermined reference level through the headend (3) to the communication medium. Each modem is arranged to properly adjust the gains of its transmitting and receiving amplifiers according to a reception level of the pilot signal for an improvement of signal transmission quality and a reliable detection of a signal collision.