Telephone line seizure circuit
First Claim
1. A telephone line seizure circuit connected between a telephone and a telephone line in which an automatic telephone dialer is connected to the telephone line, comprising:
- a first circuit for determining if the automatic telephone dialer is off-hook, wherein the first circuit detects a D.C. voltage level on the telephone line to determine if the automatic telephone dialer is off-hook;
a second circuit for disconnecting the telephone connected to the telephone line seizure circuit when it is determined that the automatic telephone dialer is off-hook, and the second circuit maintaining the telephone connected to the telephone line seizure circuit disconnected for a predetermined period of time until a central office releases the telephone line to which the telephone is connected; and
wherein the first circuit and the second circuit are powered from the telephone line.
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Accused Products
Abstract
The present invention is directed to a telephone line seizure circuit which may find particular application in home security systems which feature an automatic dialer which automatically sends an alarm detection signal out on a telephone line when an alarm condition is detected. The telephone line seizure unit of the present invention operates so that when the automatic alarm dialer is on-hook, the telephone line seizure units are transparent to the telephone system and the telephones can then be used normally. When the automatic alarm dialer goes off-hook, then the telephone line seizure unit operates to disconnect any telephone in use connected thereto, which will thereby allow the automatic alarm dialer to go back on-hook briefly, and after about 30 or so to go off-hook, to thereby utilize the telephone line to send out the alarm detection signal.
22 Citations
11 Claims
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1. A telephone line seizure circuit connected between a telephone and a telephone line in which an automatic telephone dialer is connected to the telephone line, comprising:
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a first circuit for determining if the automatic telephone dialer is off-hook, wherein the first circuit detects a D.C. voltage level on the telephone line to determine if the automatic telephone dialer is off-hook; a second circuit for disconnecting the telephone connected to the telephone line seizure circuit when it is determined that the automatic telephone dialer is off-hook, and the second circuit maintaining the telephone connected to the telephone line seizure circuit disconnected for a predetermined period of time until a central office releases the telephone line to which the telephone is connected; and wherein the first circuit and the second circuit are powered from the telephone line. - View Dependent Claims (2, 3, 4, 5)
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6. A telephone line seizure circuit connected between a telephone and a telephone line in which an automatic telephone dialer is connected to the telephone line, comprising:
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means for determining if the automatic telephone dialer is off-hook by detecting a D.C. voltage level on the telephone line to determine if the automatic telephone dialer is offhook; and means for disconnecting the telephone connected to the telephone line seizure circuit when it is determined that the automatic telephone dialer is off-hook and maintaining the telephone connected to the telephone line seizure circuit disconnected for a predetermined period of time until a central office releases the telephone line to which the telephone is connected; and wherein the means for determining if the automatic telephone dialer is off-hook and means for disconnecting the telephone connected to the telephone line seizure circuit are powered from the telephone line. - View Dependent Claims (7, 8, 9, 10)
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11. A method for seizing a telephone line connected between a telephone and a telephone line in which an automatic telephone dialer is connected to the telephone line, comprising the steps of:
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determining if the automatic telephone dialer is off-hook by detecting a D.C. voltage level on the telephone line to determine if the automatic telephone dialer is off-hook; and disconnecting the telephone connected to the telephone line seizure circuit when it is determined that the automatic telephone dialer is off-hook and maintaining the telephone connected to the telephone line seizure circuit disconnected for a predetermined period of time until a central office releases the telephone line to which the telephone is connected.
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Specification