| 摘要 |
1,265,541. Dictation apparatus. INTERNATIONAL BUSINESS MACHINES CORP. 29 May, 1969 [17 June, 1968], No. 27177/69. Heading H4K. [Also in Division G5] In the remote control of a dictating machine audio frequency tones are sent on the same line as the speech signals and are detected to provide control signals to operate a recorder where provision is made to prevent the tones being recorded. As shown, the recording assembly is connected through interface 4 to the telephone network and access is gained through hybrid 23 and A.G.C. circuit 26 to recorder 20. The recorder is of the magnetic belt type and is controlled by signals emanating from a logic circuit, Fig. 6 (not shown), which itself receives an input from tone detection circuit 30. The substation equipment 1, 2 must be provided with tone sending equipment for operating the recorder and six keys are used to provide start and stop, playback backstep, playback forward step, end letter mark, instruction mark and to call the attendant. Operation.-If recorder is functional and at least 4 minutes recording time is available standby tone is returned by the 1050 Hz oscillator 31 and the recorder can now be operated by depressing the required keys. To prevent the stop tone remaining on the tape at the end of a recorded passage, the recorder automatically reverses and erases this length of tape. End of letter and instruction marks are punched on a conjoint index tape to prevent access to previously recorded material. Timer 11 functions to disconnect the system if no action is taken by the subscriber and the attendant can interrupt using handset 38. In an alternative system, the subscribers are connected to the recorder assembly through a buffer circuit which includes a voice operated relay (VOR), Fig. 1c (not shown). In this case the changeover from ready to record is caused by the response of this relay and thus a subscriber instrument without a tone generator is able to record a message but cannot otherwise control the operation of the recorder. Voice signals after being detected in the hybrid are passed through a 200 ms. delay so that the recorder has time to be operating and does not miss any speech signals. Since the operating signals to the recorder are instantaneous with the passing of a key or operation of the VOR no control tones can be recorded but 200 ms. of speech will be lost when speaking stops, but this is not found to matter. Normally, the recorder operates on termination of a control tone as determined by latches in the logic circuitry when switched from the stop into the record mode. |
