Patent GB-914696-A (GB)
Title: Improvements in or relating to telephone systems
Inventor: HACKEY DONALD
IPC: H04M1/654
Filed: 1960-05-20
Abstract: 914,696. Magnetic tape recording apparatus; telephone answering. STANDON ASSOCIATES Ltd. May 19, 1961 [May 20, 1960], No. 17809/60. Class 40 (2). [Also in Group XXXIX] In an automatic telephone answering system using a tape recorder, a circuit responsive to an A.C. ringing signal applies an answering condition to the line after a predetermined delay and a timing circuit having two time intervals then initiates the usual sequence of events i.e. instruction to caller, recording of caller's message and release of connection. The longer of the two time intervals is adopted if pay tone (i.e. S.T.D. system) persists after the answering condition is applied, in which case the sequence referred to may be gone through, the absence of a caller's speech during " recording " leading to release of the connection or release may be effected immediately (after the longer time interval) without recourse to this sequence of events. The shorter of the two time intervals is adopted if pay tone ceases when (or soon after) the answering condition is applied, release in this case occurring a predetermined time after the caller's message is finished. The tape recorder itself is said to be of any conventional type and is connected to line 42 via a coupling unit 44. Initially switches SW1 and SW2, SW3 (interconnected) are operated, a mains supply thus being connected to a power pack 45 and to the tape recorder circuits shown generally as 30 and relay J comes up. In response to alternating ringing current on the line, valve amplifier V1 conducts sufficiently for a remanent relay A to operate. This starts a motor 38 (the spools 31, 32 not being driven yet as clutch 39 is disconnected), connects H.T. to the timing circuits which include gas discharge tubes V2-V7, transfers the anode circuit of V1 to relay K and allows a capacitor C3 in an answering delay circuit to charge. After 10-15 seconds, V2 fires and B pulls up so as to complete the D.C. loop (R3, L1) across the line and allow capacitors C4 and C5 to charge. If there is pay-tone (or other V.F. noise) on the line, relay K operates and prevents a relay D from operating for 12 seconds but if there is no pay tone, or it ceases in less than 12 seconds, D pulls up since C5 is charged within 2 seconds of relay B operating and thus V4 can fire. With D up, relay E is connected in the anode circuit of V1 and the spools are now driven forward so that the instruction message can be sent to line. E operates to this speech but on its cessation it relapses and 3 seconds later relay G operates. The calling party can now record a message and 8 seconds after he stops speaking relay N comes up. This opens the line loop but the tape is still driven on so that the instruction message is amplified by V1 to hold E operated. There is a 3-second interval between each of the identical instruction messages (these and the incoming messages are recorded on different tracks of the tape 33) and at the end of this 3 seconds relay H operates. Relay A is thus released and the apparatus restored to normal. An alternative embodiment using a separate relay in each of the anode circuits of valves V3, V4 is mentioned, the arrangement being such that if relay K is held to pay-tone, noise &c. on the line then operation of H without the intermediary steps is obtained after valve V3 fires. Near the end of the tape, a metallic portion 47 bridges contacts 48 and thus valve V8 fires to energize relay F. When relay A relapses at the end of the corresponding message the apparatus is prevented from answering any further calls due to the opened contact F1, it being arranged that once operated relay F requires external help to release.