Abstract: Sound signaling and optical signaling at a crosswalk are both activated by a single push button. An activation of optical signaling such as green and red figurines is immediate, whereas the transmission of a sound message authorizing or forbidding a crossing is activated only when the pedestrian pushes the button for a predetermined time. The generation device for sound signals is controlled by a microprocessor including logic and analog inputs and outputs, the messages being stored in digital form and transmitted according to the ADPCM method.