| 摘要 |
An attachment for a push-button telephone set which fits directly over the ten (or twelve) telephone push-buttons. On top of the attachment there is provided a separate push-button for each letter and digit. Whenever one of the attachment push-buttons is pressed down, two telephone set push-buttons are pressed down in succession so that a two-digit code is transmitted for each letter or digit without requiring the user to operate two telephone set push-buttons in succession to distinguish between letters and digits. |
