Abstract: A circuit for converting a binary input signal into a telegraph signal has constant current sources which respectively include at least one transistor with a separate bias voltage source for each transistor. The base of at least one of the transistors is connected to an input signal source. Operating voltages of opposite polarities are connected to the constant current sources, which are in turn connected to a telegraph signal output. In order to minimize the power necessary to drive the circuit, the transistors in the constant current sources, together with the respective bias voltage sources, are respectively disposed only between an operating voltage terminal and the telegraph signal output.