Patent GB-1398037-A (GB)
Title: Automatic telephone answering apparatus
IPC: H04M1/65
Filed: 1973-05-24
Abstract: 1398037 Recording and playback MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 24 May 1973 [25 May 1972 20 June 1972 (2)] 24954/73 Heading G5R [Also in Division H4] A telephone answering machine, including a multi-track endless magnetic tape, is arranged so that the tape is driven at a first speed to playback an answer message contained on one track and at a second slower speed to record a message incoming over a telephone line on a further track. In the figures, Fig. 2 shows the basic layout of the machine, Fig. 5 shows an arrangement for moving the record head 19 width-wise of the tape for recording a plurality of different incoming messages, and Figs. 7, 8 show a block diagram of the circuitry. The operation is as follows:-In the rest condition switches 71, 87 are open, roller 67 is in the notch 62 of pulley 58 and pulley 56 is not in contact with the motor flywheel small diameter portion 21a. When the telephone bell rings, detection circuit 81 causes differentiating circuit 80 to set bi-stable 79 which in turn causes supply circuit 83 to energise motor 24, amplifier 84 and solenoid 31. Capstan 25 presses the tape against motor spindle 17 to drive the tape so as to playback the answer message on the first track via head 18 to the caller. After one revolution of the tape a conductive strip passes detector 35 associated with a detection circuit 39 which causes bistable 73 to change its Q output to 1 so as to activate changeover circuit 74, thereby switching contacts 76, 77, 78, contact 76 changing the speed of the motor 17, contact 77 causing changeover of the playback and record heads 18, 19 and contact 78 preparing a warning circuit 38. The motor then drives the tape at a second lower speed to record the incoming message. Differentiating circuit 75 produces a positive pulse in response to the change of the Q output of bi-stable 73 which has no effect on bi-stable 79 or a circuit 91 to be described below. When the tape has nearly completed one revolution the conductive strip passes a second detector 34 which causes the prepared warning circuit 38 to give an audible indication to the caller that the recording period is terminating. As the conductive strip again passes detector 35 bi-stable 73 is switched back to its original state, causing changeover circuit 74 to switch contacts 76, 77, 78 thereby disengaging the tape drive and switching the heads and motor speeds to these original connections. Bi-stable 79 is reset by the negative pulse produced by differentiating circuit 75 to switch off the motor after a time determined by a delay circuit 85. This negative pulse also energizes a monostable multivibrator 92 for a time sufficient to cause transistor 89 (Fig. 8) to operate a relay 88 which in turn causes solenoid 52 to energize, the relay resetting after a predetermined time. Referring to Fig. 5 solenoid 52 causes pulley 56 to engage motor flywheel small diameter portion 21a whereby the motor drives cam 58a through one revolution to cause the record head 19 to be stepped up the width of one track via ratchet 50, 46, the solenoid 52 being held on by operation of a contact 71 associated with an arm and roller 67 which runs on the cam surface of cam 58a. At the end of one revolution contact 71 opens to de-energize solenoid 52. The drive coupling to the motor is disengaged and the motor stops under the control of delay circuit 85. An indicator is attached to the ratchet wheel 46 to indicate to which track the record head has been stepped and a knob 49 is attached, the spindle of this wheel for manually adjusting the position of the head. The record speed may be ¢, 1/3 or 2/3 of the answer message playback speed. In alternative embodiments the detectors 34, 35 are situated at the same position and the tape has two spaced pieces of conductive strip either on the same side of the tape and separated both longitudinally and width-wise of the tape or on opposite sides of the tape, the detectors being arranged accordingly.