US3909538A — Control circuit for telephone answering device wi…

Claim 1

Independent Claim 194 words

A control circuit responsive to a ringing signal on a telephone line, comprising: a silicon controlled rectifier, triggering means for initiating condition of said silicon controlled rectifier in response to occurrence of said ringing signal, a transistor, a rectifier bridge connected across said telephone line, one non-control element of said silicon controlled rectifier being connected to the base of said transistor to bias on said transistor when said controlled rectifier conducts, the other non-control element of said silicon controlled rectifier being connected to one output terminal of said bridge, the emitter of said transistor being connected via a tElephone line loading element to the other output terminal of said bridge, and a resistor connected between the base and emitter of said transistor to prevent turn-on of said transistor prior to turn-on of said silicon controlled rectifier, and a source of current connected to a utilization circuit via the emitter-to-collector path of said transistor, said transistor thereby switching on current to said utilization circuit in response to occurrence of a ringing circuit, the series circuit including said silicon controlled rectifier, the base-emitter junction of said transistor and said loading element maintaining said telephone line loaded.

Claim 2

Dependent Claim 194 words

A control circuit responsive to a ringing signal on a telephone line, comprising: a silicon controlled rectifier, triggering means for initiating condition of said silicon controlled rectifier in response to occurrence of said ringing signal, a transistor, a rectifier bridge connected across said telephone line, one non-control element of said silicon controlled rectifier being connected to the base of said transistor to bias on said transistor when said controlled rectifier conducts, the other non-control element of said silicon controlled rectifier being connected to one output terminal of said bridge, the emitter of said transistor being connected via a tElephone line loading element to the other output terminal of said bridge, and a resistor connected between the base and emitter of said transistor to prevent turn-on of said transistor prior to turn-on of said silicon controlled rectifier, and a source of current connected to a utilization circuit via the emitter-to-collector path of said transistor, said transistor thereby switching on current to said utilization circuit in response to occurrence of a ringing circuit, the series circuit including said silicon controlled rectifier, the base-emitter junction of said transistor and said loading element maintaining said telephone line loaded.

Claim 3

Dependent Claim 189 words

In a telephone answering device of the type wherein incoming messages are recorded on a reel-to-reel magnetic tape, said device including a drive motor for said magnetic tape and other electrical components for performing telephone answering operations, means, operatively connected to said drive motor and to said other components, for inhibiting subsequent answering operation of said device when insufficient tape remains on the supply reel to record additional incoming messages, comprising; a single control element on said magnetic tape near the terminal end thereof, detector means on said device for detecting the presence of said control element when substantially all of said tape has been filled with incoming messages, a ring-responsive circuit for connecting power to the drive motor and other components of said device and for loading the telephone line so as to enable automatic answering of incoming telephone calls in response to a ringing signal, and disconnection means cooperating with said circuit for disconnecting power from said motor and other components upon detection by said detector means of said control element and for keeping said telephone line loaded, so that subsequent callers will receive a busy signal.

Claim 4

Dependent Claim 189 words

In a telephone answering device of the type wherein incoming messages are recorded on a reel-to-reel magnetic tape, said device including a drive motor for said magnetic tape and other electrical components for performing telephone answering operations, means, operatively connected to said drive motor and to said other components, for inhibiting subsequent answering operation of said device when insufficient tape remains on the supply reel to record additional incoming messages, comprising; a single control element on said magnetic tape near the terminal end thereof, detector means on said device for detecting the presence of said control element when substantially all of said tape has been filled with incoming messages, a ring-responsive circuit for connecting power to the drive motor and other components of said device and for loading the telephone line so as to enable automatic answering of incoming telephone calls in response to a ringing signal, and disconnection means cooperating with said circuit for disconnecting power from said motor and other components upon detection by said detector means of said control element and for keeping said telephone line loaded, so that subsequent callers will receive a busy signal.

Claim 5

Dependent Claim 46 words

Means according to claim 2 wherein said control elements comprises a conductive segment on said tape, wherein said detector means comprises a pair of contacts shorted by said conductive segment, and wherein said circuit includes a switching component opened in response to shorting of said contacts.

Claim 6

Dependent Claim 131 words

Means according to claim 2 wherein said ring-responsive circuit comprises; a transistor having its emitter-to-collector path connected as a power switch for said answering device, a silicon controlled rectifier triggered on in response to a ringing signal, and a component for loading the telephone line, connected in series with said silicon controlled rectifier and the base-to-emitter path of said transistor across the telephone line so as to load said line when the silicon controlled rectifier conducts, and wherein said disconnection means comprises means for shorting the base-to-emitter path of said transistor in response to detection of said control element so as to switch off said transistor and hence disconnect power from said answering device, while maintaining conduction of said silicon controlled rectifier so as to continue loading of said telephone line.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-09-29	1979-03-31	1979-09-30	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-09-29	1983-03-31	1983-09-30	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-09-29	1987-03-31	1987-09-30	$7700.00	Window Closed / Lapsed

Control circuit for telephone answering device with end of tape detection means

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