Surface and interface acoustic wave couplers - consists of medium which propagates two distinct waves along two distinct paths via two series of conductors arranged transversal to paths

A data multiplex communication system comprises two units (1, 2) interconnected by lines in a loop. A first line (3) transmits time multiplexed data from the first unit (1) to the second unit (2) along a first line (3), and a second line (4) transmits data from the second first unit (1) along a second line (4). Each unit (1, 2) has a transmitting section (5, 6) for multiplexing data and has a time base synchronised by means of reference codes from generators (Mo, Mi). Each unit (1, 2) also has a receiving section (7, 8) to distribute the data to separate channels (e'O,...e'7detector (39, 40) which can supply along lines (41, 42) an alarm signal and excite a signal detector (43, 44) to stop any transmission of data when there is a loss of synchronisation.