Secure communication network comprising at least one active coupler

The network has an active coupler (1) electrically connected to multiple equipment (2,3,4,5) through communication lines (6,7,8,9) laid in star connection. The coupler has mixing logic (10), and is connected to power supply (15). Each equipment has communication controller (16,17,18,19). Mixing logic is directly connected to one controller (16) of one equipment (2). Other controllers are connected to coupler via line transceivers (12,13,14).