| 摘要 |
Method and apparatus for securing the transmission of DTMF signals by a telephone over a telephone line. If the telephone is operating in a mode wherein another party may hear any DTMF tone generated by the telephone, such as over the loudspeaker of a speakerphone or as part of a conference call, the telephone prevents generation of an audible signal which predictably corresponds to the actual DTMF value of any button pushed by the user.
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