![Touch-Tone Telephone Dialing » Cleve's Corner: Cleve Moler on Mathematics and Computing - MATLAB & Simulink Touch-Tone Telephone Dialing » Cleve's Corner: Cleve Moler on Mathematics and Computing - MATLAB & Simulink](https://blogs.mathworks.com/images/cleve/touchtone0.jpg)
Touch-Tone Telephone Dialing » Cleve's Corner: Cleve Moler on Mathematics and Computing - MATLAB & Simulink
![Telephone model from 1975.The first telephones for tone signalling of numbers were put to use in 1975 in areas with computerised telephone exchanges. The principle behind tone signalling is that each digit Telephone model from 1975.The first telephones for tone signalling of numbers were put to use in 1975 in areas with computerised telephone exchanges. The principle behind tone signalling is that each digit](https://c8.alamy.com/comp/EC7R7W/telephone-model-from-1975the-first-telephones-for-tone-signalling-EC7R7W.jpg)
Telephone model from 1975.The first telephones for tone signalling of numbers were put to use in 1975 in areas with computerised telephone exchanges. The principle behind tone signalling is that each digit
![3D Rendering of Telephone and Text Saying Ring Ring Ring Stock Illustration - Illustration of ring, metaphor: 180019039 3D Rendering of Telephone and Text Saying Ring Ring Ring Stock Illustration - Illustration of ring, metaphor: 180019039](https://thumbs.dreamstime.com/z/d-rendering-telephone-text-saying-ring-isolated-white-180019039.jpg)
3D Rendering of Telephone and Text Saying Ring Ring Ring Stock Illustration - Illustration of ring, metaphor: 180019039
![Telephone Ringtone Stock Illustrations – 314 Telephone Ringtone Stock Illustrations, Vectors & Clipart - Dreamstime Telephone Ringtone Stock Illustrations – 314 Telephone Ringtone Stock Illustrations, Vectors & Clipart - Dreamstime](https://thumbs.dreamstime.com/b/golden-telephone-1942259.jpg)