Systems and methods for integrating telephone and security devices

• US 5,799,062 A
• Filed: 03/07/1997
• Issued: 08/25/1998
• Est. Priority Date: 03/07/1997
• Status: Expired due to Term

• Current Assignee: Sal Lazzara
• Original Assignee: Allsop Incorporated
• Inventors: Sorenson, Donald C., Lazzara, Sal
• Primary Examiner(s): Chan, Wing F.
• Application Number:
  US08/813,912
• Time in Patent Office: 536 Days
• Field of Search: 379/38-40, 379/45, 379/50, 379/51, 379/93.02, 379/93.05, 379/184, 379/194, 379/195, 379/354-356, 379/377, 379/387, 379/441, 379/442
• US Class Current: 379/51
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

A system or method for interconnecting a security system with a telephone system. The system comprises one or more lockout modules that are connected between non-priority telephone devices and a telephone line. A security panel is directly connected to the telephone line. The lockout modules comprise a switch means for disconnecting the telephone device attached thereto from the telephone line when the security panel connects to the telephone line. The lockout modules further comprise a latch device that gives the first non-priority telephone device to connect to the line exclusive use of the line against other non-priority telephone devices. The lockout module further comprises a circuit that inhibits the reconnection of the telephone devices to the line to allow the security panel to recover a high and dry telephone line. The lockout module may be modified to include a switch that allows other non-priority telephone devices to share the line.

Claims

1. A lockout circuit for allowing a security system to access a telephone line connected to at least one telephone device, comprising:

first and second circuit nodes connected in series with each telephone device such that a terminal voltage is present across the first and second circuit nodes; and

voltage offset means for creating an offset voltage between the first and second nodes, where the offset voltage has a first predetermined voltage level; and

latch means in series with the voltage offset means for allowing current to flow between the first and second circuit nodes only if current begins flowing through the latch means when the terminal voltage is above a second predetermined voltage level.

2. A lockout circuit as recited in claim 1, further comprising switch means connected in series with the offset means, where the switch means opens after the terminal voltage goes below a third predetermined voltage and closes a predetermined time period after the terminal voltage exceeds the third predetermined voltage.

3. A lockout circuit as recited in claim 1, further comprising a diode bridge connected between the lockout circuit and the telephone line.

4. A lockout circuit as recited in claim 1, in which the voltage offset means comprises a Zener diode, where the first predetermined voltage level is determined by a breakdown voltage of the Zener diode.

5. A lockout circuit as recited in claim 1, in which the voltage offset means comprises first and second Zener diodes the cathodes of which are connected together.

6. A lockout circuit as recited in claim 1, in which the latch means comprises at least one circuit device selected from a group consisting of a silicon trigger switch, a diac, a thyrister, and a transistor.

7. A lockout circuit as recited in claim 2, in which the second switch means comprises a switch circuit connected in series with the voltage offset means and a control circuit for controlling the switch circuit.

8. A lockout circuit as recited in claim 7, in which the control circuit comprises a Zener diode and an RC circuit, where the third predetermined voltage is determined by a breakdown voltage of the Zener diode and the first predetermined time period is determined by a time constant associated with the RC circuit.

9. A lockout circuit for allowing a security system to access a telephone line connected to at least one telephone device, comprising:

first and second circuit nodes connected in series with each telephone device such that a terminal voltage is present across the first and second circuit nodes; and

voltage offset means for creating an offset voltage between the first and second nodes, where the offset voltage has a first predetermined voltage level; and

switch means connected in series with the offset means, where the switch means opens a first predetermined time period after the terminal voltage goes below a second predetermined voltage level and closes a second predetermined time period after the terminal voltage exceeds the second predetermined voltage level.

10. A lockout circuit as recited in claim 9, further comprising a diode bridge connected between the lockout circuit and the telephone line.

11. A lockout circuit as recited in claim 9, in which the voltage offset means comprises a Zener diode, where the first predetermined voltage level is determined by a breakdown voltage of the Zener diode.

12. A lockout circuit which recited in claim 9, in which the switch means comprises a switch circuit connected in series with the offset means and a control circuit for controlling the switch circuit.

13. A lockout circuit as recited in claim 12, in which the control circuit comprises a Zener diode and an RC circuit, where the second predetermined voltage level is determined by a breakdown voltage of the Zener diode and the first predetermined time period is determined by a time constant associated with the RC circuit.

14. A method of connecting a security system to a telephone line comprising first and second conductors, the method comprising the steps of:

connecting a dialer portion of the security system to the telephone line;

providing a lockout circuit for each telephone device connected to the telephone line, where each lockout circuit comprises

voltage offset means for creating an offset voltage having a first predetermined voltage level, and

switch means connected in series with the offset means, where the switch means opens after the terminal voltage goes below a second predetermined voltage level and closes a predetermined time period after the terminal voltage exceeds the second predetermined voltage level; and

connecting one of the lockout circuits in series with each of the telephone devices.

16. An integrated system as recited in claim 14, further comprising switch means connected in series with the offset means, where the switch means is operable to prevent current from flowing through the associated local telephone device.

17. An integrated system as recited in claim 16, in which the switch means prevents current from flowing to the associated local telephone device for a first predetermined time period after the terminal voltage goes below a third predetermined voltage level.

18. An integrated system as recited in claim 14, further comprising switch means connected in series with the offset means, where the switch means prevents current from flowing to the associated local telephone device for a first predetermined period after the terminal voltage goes below a third predetermined voltage level.

19. An integrated system as recited in claim 14, in which the offset means comprises a Zener diode, where the first predetermined voltage level is determined by a breakdown voltage of the Zener diode.

20. An integrated system as recited in claim 14, in which the offset means comprises first and second Zener diodes the cathodes of which are connected together.

21. An integrated system as recited in claim 14, in which the latch means comprises a device selected from the group consisting of a silicon trigger switch, and a transistor.

22. An integrated system as recited in claim 17, in which the switch means comprises a switch circuit connected in series with the first switch means and a control circuit for controlling the switch circuit.

23. An integrated system as recited in claim 22, in which the control circuit comprises a Zener diode and an RC circuit, where the third predetermined voltage is determined by a breakdown voltage of the Zener diode and the first predetermined time period is determined by a time constant associated with the RC circuit.

15. An integrated telephone/security system, comprising:

a telephone network for transmitting telephony signals;

a first telephone line at a local premises, the first telephone line being connected to the telephone network;

a second telephone line at a remote premises, the second telephone line being connected to the telephone network;

a remote telephone device at the remote premises, the remote telephone device being connected to the second telephone line;

a security system for detecting security conditions at the local premises, the security system comprising dialer means connected to the first telephone line for transmitting security data indicative of detected security conditions to the remote telephone device;

at least one local telephone device at the local location;

a lockout circuit associated with each local telephone device, each lockout circuit being connected in series with its associated local telephone device;

wherein

each lockout circuit comprises offset means for creating an offset voltage having a first predetermined voltage level, where the offset means is connected in series with the local telephone device;

the first predetermined level is selected such that, when the dialer means connects to the local telephone line, a voltage across the local telephone devices is insufficient to allow the local telephone devices to connect to the local telephone line, thereby providing the dialer means with exclusive access to the local telephone line; and

latch means in series with the voltage offset means for allowing current to flow to the associated local telephone device only if current begins flowing through the latch means when the terminal voltage is above a second predetermined voltage.

24. A method of connecting a security system to a telephone line comprising first and second conductors, the method comprising the steps of:

connecting a dialer portion of the security system to the telephone line;

providing a lockout circuit for each telephone device connected to the telephone line, where each lockout circuit comprises

voltage offset means for creating an offset voltage having a first predetermined voltage level, and

latch means in series with the voltage offset means for allowing current to flow between the first and second circuit nodes only if current begins flowing through the latch means when the terminal voltage is above a

second predetermined voltage level; and

connecting one of the lockout circuits in series with each of the telephone devices.

25. A lockout device for allowing a security system to access a telephone line having first and second line conductors connected to first and second telephone conductors of at least one telephone device, comprising:

first, second, and third circuit conductors;

a first connector assembly for connecting the first and second circuit conductors to the first and second line conductors;

a second conductor assembly for connecting the first and third circuit conductors to the first and second telephone conductors;

a diode bridge having first, second, third, and fourth bridge nodes, where the first and third bridge nodes are connected to the second and third circuit conductors;

first and second circuit nodes connected to the second and fourth bridge nodes; and

a first Zener diode connected between the first and second circuit nodes, where the Zener diode allows current to flow between the first and second circuit nodes when a voltage across the circuit nodes is above a first predetermined voltage level and prevents current from flowing between the first and second circuit nodes when the voltage across the circuit nodes is below the first predetermined voltage level.

26. A lockout device as recited in claim 25, further comprising:

a switch circuit connected in series with the first Zener diode; and

a control circuit for operating the first switch circuit to allow current to flow between the first and second circuit nodes a predetermined time period after the voltage across the first and second circuit nodes goes above a second predetermined voltage level and to prevent current from flowing between the first and second circuit nodes when the voltage across the first and second circuit nodes goes below the second predetermined voltage level.

27. A lockout device as recited in claim 26, in which the control circuit comprises:

a control resistor and control capacitor connected in series across the first and second circuit nodes such that the capacitor is charged by the voltage across the first and second circuit nodes; and

a second Zener diode connected between the control capacitor and the switch circuit such that when a control voltage across the control capacitor exceeds the breakdown voltage of the second Zener diode current flows through the second Zener diode, thereby controlling the switch circuit to allow current to flow between the first and second circuit nodes.

28. A lockout device as recited in claim 27, further comprises a silicon trigger switch arranged in series with the first Zener diode between the first and second circuit terminals, where the silicon trigger switch allows current to flow between the first and second circuit terminals if current begins flowing through the silicon trigger switch when the voltage across the first and second circuit nodes exceeds a third predetermined voltage level.

29. A lockout module for providing access to a telephone line to one of a plurality of telephone devices, where the telephone line comprises first and second telephone line conductors and the telephone devices are each assigned to one of a plurality of priority levels including a first, relatively higher, priority level and a second, relatively lower, priority level, the lockout module comprising:

connecting means for connecting the module in line with an attached telephone device assigned to the second priority level such that current flowing through the first and second conductors to the attached telephone device flows through the lockout module;

first and second circuit nodes connected to the first telephone line conductor;

offset means for establishing an offset voltage between the first and second circuit nodes, where the offset means effectively disconnects the attached telephone device from the telephone line when the voltage across the first and second circuit nodes falls below a predetermined offset voltage level; and

switch means arranged in series with the offset means for selectively allowing current flow between the first and second circuit nodes in response to a control signal; and

control means for generating the control signal.

30. A lockout module as recited in claim 29, further comprising indicating means for indicating whether current is flowing to the attached telephone.

31. A lockout module as recited in claim 30, in which the indicating means comprises a light-emitting diode and shunt means for shunting excess current around the light-emitting diode.

32. A lockout module as recited in claim 31, in which the shunt means comprises a transistor and a resistor, where the light-emitting diode is connected between the base and the collector of the transistor and the resistor is connected between the between the emitter and the base of the transistor.

33. A lockout module as recited in claim 29, control means generates the control signal if no other telephone device has been connected to the telephone line for a predetermined period of time before the attached telephone device attempts to connect to the telephone line.

34. A lockout module as recited in claim 33, in which the control means comprises trigger means for generating a trigger signal based on a voltage across the first and second telephone line conductors, where the control means generates the control signal whenever the trigger signal is present.

35. A lockout module as recited in claim 34, in which the trigger means generates the trigger signal when the voltage across the first and second telephone line conductors exceeds a predetermined trigger voltage for a predetermined trigger charge period.

36. A lockout module as recited in claim 35, in which the trigger means generates the trigger signal for a predetermined trigger discharge period after the voltage across the first and second telephone line conductors falls below the predetermined trigger voltage.

37. A lockout module as recited in claim 36, in which the trigger means comprises a trigger capacitor and a trigger Zener diode connected in series between the first and second telephone line conductors such that the trigger capacitor is charged by a voltage across the first and second telephone line conductors and the trigger Zener diode generates the trigger signal as long as (a) the attached telephone device connects to the telephone line and (b) a voltage across the trigger Zener diode exceeds a breakdown voltage of the trigger Zener diode.

38. A lockout module as recited in claim 36, in which the control circuit comprises latch means for generating a latch signal a predetermined latch charge period after the attached telephone device has connected to the telephone line, where the control circuit generates the control signal whenever the latch signal is present.

39. A lockout module as recited in claim 38, in which the predetermined latch charge period is shorter than the predetermined trigger discharge period.

40. A lockout module as recited in claim 29, in which the control means comprises latch means for generating a latch signal a predetermined latch charge period after the attached telephone device has connected to the telephone line, where the control circuit generates the control signal whenever the latch signal is present.

41. A lockout module as recited in claim 40, in which the latch means comprises a holding capacitor that begins charging when the attached telephone device connects to the telephone line and is discharged when the attached telephone device disconnects from the telephone line.