| 摘要 |
A telephone system provides an alternative to being kept "on hold". When placed on hold, *8 or some other code can be dialed, which allows the party placed on hold to hang up his or her phone without disconnecting the call. To resume the call, the party that placed the call on hold dials any number on his or her phone and the phone of the party that had been placed on hold rings to signify that the call is off hold and can be resumed. When the call back is answered the call is resumed. In a first embodiment, the callback on hold operation is performed in cooperation with a telecommunication company's central office switch. In a second embodiment, dedicated circuitry and microprocessor firmware are added to consumer telephone equipment, performing the callback on hold operation without requiting any specific support from a central office switch. The present invention is disclosed in the environments of telephones, answering machines, combination telephone and answering machines, both corded and cordless telephones (with or without answering machines), cellular telephones, and standalone devices attachable between a telephone and/or answering system and the central office telephone lines. A "hold on hold" indicator lamp may optionally be employed. The indicator lamp circuitry detects brief DTMF tone pairs to signal the operation of a hold LED with a unique cadence indicating of a callback hold, rather than a normal hold condition. |
