| 摘要 |
A dual-tone generating telecommunication device comprising a frequency generating element that produces at least 9 individual tones, each having a distinct frequency between 300 Hz and 3,000 Hz, and at least 17 dial buttons, with each dial button representing at least one distinct character, and where each character directs the frequency generating element to produce a distinct dual tone, with each distinct dual tone being generated by the combination of two different individual tones.
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