Data Communication system

摘要

A plurality of secondary stations (41, 42, ..., 4n) are connected in parallel to a two-wire transmission line in a data communication system. The secondary stations are dialled by modulation of the voltage (e) on the transmission line (L) by means of calling signals. The data are transmitted from the secondary stations (41, ..., 4n) by modulation of the current on the transmission line (L). The invention is applied in measured variables communication systems. <IMAGE>