Patent GB-1515176-A (GB)
Title: Recording and reproducing machines
IPC: H04Q9/12
Filed: 1975-07-28
Abstract: 1515176 Recording and playback apparatus ANSAFONE LTD 28 July 1975 [26 July 1974] 31514/75 Divided out of 33228/74 Heading G5R A machine which records and reproduces electric input signals by means of a magnetic head H on a magnetic tape 5 driven forwardly by a motor FM has a control arrangement which ensures that when the end of the most recently recorded signal in the tape 5 is adjacent head 5 the tape can only be driven forwardly if the machine is set to the recording node and ensures that the record mode cannot be selected if said signal end has been moved rearwardly of the head H, so that a succeeding signal will always be recorded on the section of the tape 5 succeeding the end of the most recently recorded signal. The invention may be applied to recording/playback of video or data signals, but is illustrated in the form of a telephone answering machine to record incoming messages on telephone line L1, L2 and, by operation of controls on the machine or in response to control signals on a telephone line, to reproduce such messages. An incoming ringing signal on line L1, L2 is detected by detector D which, after a delay, closes a switch S1 whereupon control link CU energizes a motor to drive an answering text tape (both not shown) which is replayed into line L1, L2 by a head (not shown) connected by unit CU to amplifier A. Unit CU then closes record switch S3 and switches a switching circuit S to a record mode in which line L1, L2 is connected to the input of amplifier A, the output of which is connected to record/replay head H so that the incoming message is recorded thereby on tape 5, driven by motor FM in response to AND gate G1 being enabled by a signal on line F from unit CU. At the end of the allowed recording period, or when the caller hangs-up if the machine is voice-controlled, unit CU stops motor FM, puts circuit S in a standby mode, opens switch S3, and operates a solenoid 9 to decouple a tape counter C from take-up spool 3 and cause counter C to rotate to its zero position in which a switch S2 associated therewith is open. Switch S2 is only closed in a range of counts of counter near the maximum count thereof and just before it starts from zero again after going through the maximum. In the standby state forward drive by motor FM can only be obtained by engaging the record mode. When the machine owner starts tape rewind from the standby starter switch S2 closes immediately and a memory M in unit CU gives a logic 1 to OR gate G5. If rewind extends by an amount to reduce the counter count below said range, S2 opens, whereby if the machine is then switched to a record mode S3 is closed but forward tape drive by motor FM is prevented due to gate G1 being disabled by a "0" input from inverter I1 receiving a "1" input via OR gate G5 from memory M in unit CU. If S2 was still closed at the end of the rewind, inverter I1 would accordingly still give a "0" output even though memory M would then give a "0" output on selecting a forward drive mode. Playback or fast forward can, however, be selected following rewind in either case, since with record switch S3 open AND gate G2 can be enabled, on receiving a signal on line F from unit CU, to energize motor FM via OR gate G4. Fast forward or playback is terminated when gate G5 output goes to "0" when switch S2 opens or the head H reaches the end of the last message and counter C returns to zero, and unit CU puts the machine in a standby state wherein AND gate G3 gives a "1" output to operate a relay R, contacts of which thereby energize a standby lamp L and energize detector D. A tone generator may give a pre-determined signal when the end of the last recorded message on tape 5 reaches head H during the playback or fast forward mode. An erase head for tape 5, operating during recording, may also be energized during rewind, control unit CU resetting counter C to zero at the end of such an erase operation.