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| äänitaajuusvalinta (The signaling system used in telephones with touchtone keypads, in which each digit is associated with two specific frequencies); DTMF (The signaling system used in telephones with touchtone keypads, in which each digit is associated with two specific frequencies) | |||
| 英语 词库 | |||
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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 | |||