Patent GB-1492933-A (GB)
Title: Telephone answering machines
IPC: H04M1/65
Filed: 1974-11-14
Abstract: 1492933 Telephone answering machines ANSAFONE Ltd 14 Nov 1974 [14 Nov 1973 14 May 1974] 52793/73 Heading G5R A telephone answering machine on detecting a ringing current on a connected telephone line first reproduces a recorded answering text, and then records an incoming message on an endless recording medium, and a control circuit is operative so that when a plurality of messages have been so recorded on said medium subsequent application of an electrical command signal for reproducing the messages causes the last-recorded message to be reproduced first. The control is preferably arranged so that the messages are reproduced in the reverse order from the order in which they were recorded. The machine uses a ¢ in. wide, 60 in. long endless magnetic tape (1), Fig. 1 (not shown), having a blank track (0) along a bottom edge, 15 message recording tracks thereabove and a track 16 along the top edge carrying an answering text comprising an opening text (3) and a closing text (5), a metal strip (7) being provided on the tape to bridge pairs of contacts A 0 , A 000 ; B 0 , B 00 ; C 0 , C 00 ; P 0 , P 00  of the control circuit, Fig. 4. In a standby condition strip (7) is just beyond contacts A and the start of text (3) just before contacts A, contacts B, and shortly thereafter P and C, being bridged by strip (7) after about 25 sees. of the 30 secs. needed for drive of tape (1) by a capstan motor M once round a predetermined path. The answering track (16) is played back by a fixed head AH, Fig. 4, and tracks 1 to 15 are recorded/replayed by a combined record/playback/erase head MH, movable by means of a rack 27 and a pinion 25 Fig. 3, on a shaft 21 carrying a head position indicator 59 and cams 23 operating leaf switches LC16, LCC, Fig. 4, shaft 21 being manually rotatable by a knob 51 or automatically by a stepping motor MS driving a switching plate 19 to which are pivoted pawls 35, 37 operable on head raise 31 and lower 33 ratchets respectively. Motor MS may be replaced by two solenoids. Operation.-When an outside telephone call produces a ringing current on line L1, L2, Fig. 4, SCR1 is turned on by current from rectifier bridge MR whereby relay RL1 is energized. Thus, a primary of transformer TR is connected across line L1, L2 to complete a loop to the telephone exchange, and tape drive motor M and playback amplifier PA-shown twice, as is recording amplifier RA, for convenience-are energized whereby head AH replays the opening (3) of the answering track (16) and when strip (7) bridges contacts C 0 , C 00 , capacitor C3 discharges whereby SCR2 fires to turn off playback amp. PA and turn on record amp. RA, and transistors T7, T8 turn on to energize motor MS and step head MH to track 1 or the track immediately above the last one of the message tracks to have been recorded, whereby during the next traverse of tape loop (1) the incoming message is recorded on the selected track and then when strip (7) has bridged contacts B 0 , B 00  and C 0 , C 00 , head AH plays back the closing part (5) of the answering text and the apparatus then stops in the standby condition. The final message track, 15, can carry an announcement indicating that all tracks are full and is played back, when this condition is reached, at each incoming call. The apparatus owner may replay the recorded message tracks by 'phoning from a remote location whereupon the answer text (3) is initially played back and during this time the owner sends an audio tone of predetermined frequency over line L1, L2 to be sensed by detector TD resulting in head MH being moved to the track above the last-recorded message track and being connected to the playback amplifier PA, subsequent bridging by strip (7) of contacts P 0 , P 00  moving head MH down to the last-recorded message track which is thereby replayed into line L1, L2 via the secondary of transformer TR when contacts C 0 , C 00  are bridged, bridging of contacts P 0 , P 00  during replay of the last message stepping head MH down to next replay the penultimate message and so on until head MH is stepped to track 0 and a can 23 on shaft 21, Fig. 3, opens switch LCC, Fig. 4, resulting in replay of the closing answer text (5) and then return to the standby condition. Transmission of n pulses of the predetermined audio frequency steps head MH up (n-1) tracks allowing repeated playback of any desired tracks. Other controls (not detailed or shown except for switches LP1, LP2, Fig. 4) allow recording of the answer track 16 and local playback via a loud-speaker of the message tracks. Means for sensing jamming or breakage of the tape is sensitive to the level of D.C. in amplifier PA when a call is received and if the D.C. level is low-text (3) not being transmittedhead MH is moved to track 16 and further operation of the apparatus is inhibited. In modifications one or more of the contact pairs B 0 , B 00 , P 0 , P 00 , C 0 , C 00  may be replaced by a timer, a fixed sixteen-track head with a head switching circuit may be used instead of the movable head MH, and strip (7) may be replaced by a photo-electric detector or a tape section may be provided with means actuating a magnetic, electrical or mechanical sensor. In a further modification. Figs. 5A to 5C (not shown), a tape with two laterally and longitudinally spaced contact-bridging foils (MF1), (MF2) is used in apparatus having a simplified head shifter and a common record and playback amplifier (A). An alternative embodiment (not shown or detailed) uses a taut band, or tape, record medium with means for causing lateral shift of the band or preferably of a record/playback head. The tape or band may have perforations and/or edge notches or a separate element to trigger head shifting, with electrical, magnetic or mechanical tape position sensing. The tape or bands may act as an escapement mechanism to initiate operation of a mechanical headshifter powered directly from the tape drive mechanism.