A signal transmission system comprising an interface circuit and a transmission line, the interface circuit comprising: a signal line (L) having signal , auxiliary and connection nodes defined therealong, the connection node connected to the transmission line; signal-handling circuitry connected to the signal line (L) at the signal node so that an effective capacitance of the signal-handling circuitry is experienced at the signal node ; an auxiliary circuit connected to the signal line (L) at the auxiliary node so that an effective capacitance of the auxiliary circuit is experienced at the auxiliary node ; a signal pair of inductors connected along the signal line (L) adjacent to the signal node and at either side of the signal node ; and an auxiliary pair of inductors connected along the signal line (L) adjacent to the auxiliary node and at either side of the auxiliary node , wherein: the signal pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kS; the auxiliary pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kA; for each said pair of inductors , the inductors of the pair are arranged such that a current flowing along the signal line (L) in a given direction through one of those inductors induces a current flowing along the signal line (L) in the same direction in the other one of those inductors given a positive coupling coefficient; and kS has a positive value and kA has a negative value. a signal line (L) having signal , auxiliary and connection nodes defined therealong, the connection node connected to the transmission line; signal-handling circuitry connected to the signal line (L) at the signal node so that an effective capacitance of the signal-handling circuitry is experienced at the signal node ; an auxiliary circuit connected to the signal line (L) at the auxiliary node so that an effective capacitance of the auxiliary circuit is experienced at the auxiliary node ; a signal pair of inductors connected along the signal line (L) adjacent to the signal node and at either side of the signal node ; and an auxiliary pair of inductors connected along the signal line (L) adjacent to the auxiliary node and at either side of the auxiliary node , wherein: the signal pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kS; the auxiliary pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kA; for each said pair of inductors , the inductors of the pair are arranged such that a current flowing along the signal line (L) in a given direction through one of those inductors induces a current flowing along the signal line (L) in the same direction in the other one of those inductors given a positive coupling coefficient; and kS has a positive value and kA has a negative value. the signal pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kS; the auxiliary pair of inductors are configured to have a mutual coupling defined by a coupling coefficient kA; for each said pair of inductors , the inductors of the pair are arranged such that a current flowing along the signal line (L) in a given direction through one of those inductors induces a current flowing along the signal line (L) in the same direction in the other one of those inductors given a positive coupling coefficient; and kS has a positive value and kA has a negative value. <EOS>