A communication system includes a first system input adapted to be coupled to a DC transient current transitioning between a starting level and a target level on a pseudo-sinusoidal path and incudes a second system input adapted to be coupled to a HART signal. The system includes an adder circuit having an output, a first adder input coupled to the first system input and a second adder input coupled to the second system input. The adder circuit provides a superimposed signal comprising the HART signal and the DC transient current.