| 摘要 |
<p>ARRANGEMENT FOR PROVIDING SIGNALLING TONES AND VOLUME CONTROL SIGNALS A keyboard with number and volume control pushbuttons is provided with a microcomputer, a digital-to-analog converter, and an output circuit to provide signalling tones to a radio transmitter in response to operation of the number pushbuttons, and to provide volume control signals to a radio receiver in response to operation of the volume control pushbuttons.</p> |
