GB1536843A - Telephone answering machines - Google Patents

Abstract

1536843 Telephone answering machine ANSAFONE Ltd 22 Dec 1975 [24 Dec 1974] 55880/74 Heading H4K A telephone answering machine which reverts a tone signal to a calling subscriber so that he may signal his own number to the machine for storage therein, comprises an automatic dialler that is enableable by the machine owner so as to "dial" the stored number. Operation.-When the owner-subscriber is absent a detector circuit 1 is enabled by the closure of switch S1 so that persistent incoming ringing current is effective to operate relay A whose contacts Al and A2 respectively loop the line and actuate the control circuit 3. The latter enables a control circuit 6 which holds relay A even when the ringing current ceases and a tone generator 5 which applies a predetermined tone to line L1, L2. The caller on receipt of the tone dials his own number. The dialled signal is shaped by pulse shaper 7 and stored in store 9 via binary/decimal converter 11. When the dialled signal ceases, control circuit 3 de-energizes relay A through circuit 6, and energizes an indicator light L. Subsequent caller's numbers are stored, in order, up to a maximum of, e.g. 10. The owner-subscriber can call back the earliest caller by lifting his handset and pressing button PB which actuates the control circuit 3; relay A is energized through circuit 6 and the line is looped by contacts Al. A detector 13 responds to dial tone and signals to the control circuit 3, which via circuit 8 energizes relay B whose contacts Bl short-circuit the line. The control circuit 3 causes store 9 to be read out so that voltage pulses representing the stored number are applied to the line through contacts Al of relay A. If the caller has been contacted his number is erased from the store by pressing button CB. Subsequent calls are similarly treated. If the owner-subscriber presses switch S2 instead of button PB in addition to the stored number being called the dialling pulses are stored by the shaper circuit 7 and by subsequently pressing button PB, the same number, stored in circuit 7, can be dialled. The caller's set may be modified by additional circuits, so that it can store the caller's number and automatically transmit it to an absent subscriber's machine on reception of the predetermined tone signal.