Abstract: To decode multifrequency dialing signals transmitted by a pushbutton-equipped subscriber station of a telecommunication system and quantized upon arrival at a central office, a receiver at the office includes two digital filters separating the incoming binary-coded samples from sine waves in a higher and a lower frequency range and supplying the respective sets of samples to two interpolators converting them into respective square waves fed to a decoder. Each interpolator comprises a sign-bit extractor and an arithmetic unit which emits a numerical value--based on the absolute values of two consecutive samples--representing a delay expressed as a number of clock pulses recurring at a multiple of the sampling rate.