Abstract: To broadcast a two-tone attention signal to receivers, a two-tone generator includes an interrupt switch, which, when a button is depressed, interrupts the audio signal from a broadcasting station and instead applies two combined frequencies which have been generated to the broadcast audio chain to modulate the carrier with the two-tone attention signal and broadcast it. To generate the two frequencies, a single clock frequency is applied to two different frequency dividers which digitally divide the clock frequency into the desired two tones. The two frequencies from the two dividers are applied to sine-wave generators which first differentiate the pulses from the digital circuits and then apply them to tank circuits. The time duration of the two signals is controlled by a digital system which counts 60 Hertz pulses for a predetermined time period after the button is depressed prior to terminating the two-tone attention signal.