EDN Access -- 02.03.94 Circuit vocalizes telephone numbe
Design Ideas:February 3, 1994
Circuit vocalizes telephone number
Chun-Shan Institute of Science and Technology, Lung-Tan, Taiwan
The circuit in Fig 1 is a simple method of vocalizing the digit number of a telephone keypad, which, for someone visually impaired, provides helpful voice confirmation. A 75T202 dual-tone multifrequency (DTMF) receiver decodes the DTMF signal when you depress the phone's keypad. The TC8801N voice synthesizer outputs the voice data corresponding to the data input code. A TA7368P audio power IC amplifies the result. The logic gates perform necessary code conversion for the voice-synthesizing IC's input. (DI #1357)EDN Magazine. EDN is a registered trademark of Reed Properties Inc, used under license.