| 摘要 |
A controller circuit enables remote control of conventional answering machines from any DTMF-capable telephone coupled to the same telephone line to which the answering machine is coupled, and within the same dwelling (such a telephone is referred to as a "local remote-control" telephone). The controller is coupled between the answering machine and the telephone line, and in a first mode of operation is transparent to the answering machine. When activated by a DTMF security code transmitted from a local remote-control telephone, the controller enters a second (local remote-control) mode of operation. The controller in this second mode causes the answering machine to pick up the line as if answering a call. DTMF signals transmitted by the local remote-control telephone are coupled by the controller to the answering machine for enabling remote control of the machine (e.g., to retrieve recorded messages). The controller also reduces the magnitude of supervisory tones and audio messages transmitted onto the telephone line from a Central Office while the local remote-control telephone is off-hook retrieving messages from the answering machine, to minimize interference between these signals and retrieved messages being heard through the local remote-control telephone. A version of the controller may be embodied within an improved telephone answering machine to provide local remote-control capabilities.
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