Patent ID: 7859427

Claim:
An arrangement for electrically isolated transmission of direct-current and alternating-current signals between a first transmit-and-receive system ( 1 ) and a second transmit-and-receive system ( 2 ), comprising: sections of transmit-and-receive conductor pairs ( 6 a , 6 b ; 7 a , 7 b ; 8 a , 8 b ), which connect the two transmit-and-receive systems ( 1 , 2 ) via a single two-conductor channel; a direct-current transmitter ( 4 ) including an isolating converter ( 3 ) with a primary circuit ( 45 ) and a secondary circuit ( 46 ), which is short-circuited for the signal transmission with direct-current signals (IN 1 , IN 2 ), wherein the direct-current transmitter ( 4 ) converts direct-current signals (IN 1 ) into alternating-current signals and these back into direct-current signals (IN 2 ) for DC isolation of the conductor sections; an electronic I/I or I/U converter ( 5 ), on whose input side the signals transmitted via the channel are applied and on whose output side usable signals are output as current or voltage signals to the second transmit-and-receive system ( 2 ); and a message signal transmitter ( 9 ), which is connected on the secondary side to the direct-current transmitter ( 4 ) for the transmission of the message signal (U 2 ), so that, on the primary side, a change in voltage can be determined, which can be evaluated by the first transmit-and-receive system ( 1 ) as the transmitting message signal.