GB1265542A - - Google Patents

Abstract

1,265,542. Dictation apparatus. INTERNATIONAL BUSINESS MACHINES CORP. 29 May, 1969 [17 June, 1968], No. 27178/69. Heading H4K. In remote dictation apparatus where the recorder is controlled by transmitted audio frequency tones, these control tones are erased from the record medium by reversing the drive and applying an erasing signal while the medium travels a predetermined distance. To enter the record mode a control tone is sent which is detected and used to set latch 41, energize recording oscillator 46 and energize motor 61 through transistors 55, 65 to drive recording medium 43. If a further control tone is now sent it will not be detected immediately and a portion will be recorded. Once the tone is recognized AND gate 73 is operated to set motor reverse latch 51 which after a delay resets record latch 41. Latch 51 causes transistors 81, 83 to conduct, thereby reversing the motor and also energizes oscillator 46 which applies an erase signal to head 45. As the motor moves in the reverse direction contact 85 is moved until it contacts a fixed contact which operates to reset the reverse latch 51 and stop the motor. In this state the recording oscillator is not operating as nothing is recorded on the recording medium. In a modification, Fig. 3 (not shown), the terminal portion of a " start recording " tone is prevented from being recorded by means of a transistor switch (101) which remains off as long as tone is being detected. This circuit also uses an electronic timing device to determine the distance through which the recording medium is reversed to erase the control tones.