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| 双音调多声频; 双音复频 | |||
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| 複頻式訊號 (The signaling system used in telephones with touchtone keypads, in which each digit is associated with two specific frequencies) | |||
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| 双音多频 | |||
| Anglais glossaire | |||
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| Dual Tone Multiple-Frequency (The signaling system used in telephones with touchtone keypads, in which each digit is associated with two specific frequencies) | |||
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| DTMF | |||
