PURPOSE: To prevent the malfunction and the erroneous connection of a dial signal receiver without any distortion in a transmitted signal, by generating a dial signal which has no DC component.

CONSTITUTION: The signal (a) of a dial push-button matrix 1 arrives at a dial signal generating IC2, which generates a dial signal (b) and a muting signal (f), which is attenuated by an attenuator 8 into a signal (g) which is a half as high as the maximum level of the signal (f). The signals (g) and (b) are inputted to and added together by an adder 10 to obtain the signal c' which has no DC component. The signal c' is passed through an LPF3 to remove its higher harmonic signal components, and the resulting signal, i.e. signal c" is inputted to a differential amplifying circuit 4 to output a signal d'. The signal d' is outputted as a signal e' from wired communication line terminals 6a and 6b.