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Publication numberUS3854127 A
Publication typeGrant
Publication dateDec 10, 1974
Filing dateSep 18, 1973
Priority dateSep 18, 1973
Publication numberUS 3854127 A, US 3854127A, US-A-3854127, US3854127 A, US3854127A
InventorsDamon C
Original AssigneeDamon C
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Alarm system with automatic ringback
US 3854127 A
Abstract
An alarm system which senses, at a central location, change from day monitoring to night monitoring at the remote location and automatically sends a ringback signal to the remote location to indicate that the change has been received and noted. The ringback signal is a repetitive signal for a given number of repetitions. The central location includes an indication of the change which remains activated until the central monitor is reset and switched to night monitoring.
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United States Patent [191 Damon Dec. 10, 1974' 3,618,082 11/1971 Feulner 340/413 Primary ExaminerJohn W. Caldwell [76] Inventor: Clarence Stanley Damon, 6758 Penn I Kansas City 641 I3 Assistant Examiner-Richard P. Lange Attorney, Agent, or FirmFidelman, Wolffe, Leitner 22 Filed: Sept. 18, 1973 & Hiney [21] Appl. No.: 398,301

- ABSTRACT 340/226 A'n alarm system which senses, at a central location, hilt. Cl. hange from day monitoring to night monitoring at the Fleld of Search 340/2131, remote location and automatically sends a ringback 3 l4, 163, 413 signal to the remote location to indicate that the change has been received and noted. The ringback References Cited signal is a repetitive signal for a given number of repe- UNITED STATES PATENTS titions. The central location includes an indication of 2,978,676 4/1961 Spencer 340/226 the Change which remains activated until the Central 3 0 9 73 12 9 2 w et aL I I I I 340/226 monitor is reset and switched to night monitoring.

3,287,7l7 ll/l966 Kraus r 340/2l3.l I 3,585.620 6/1971 Durand 340/2132 18 Clams 2 Drawmg F'gures CENTRAL l0 l r I. 1 I I l I TAZ ZONE 1 l l l i O 0% A I I? l "m4 I i I l l l I TBI l I T52 ZONE 1 T83 B l T84 I l l l I I I l l I I TCI [l3 r -"1I I6 I T4 0 ZONE 1C5 l ea f REMOTE c I -l 0 oc l I I OM I l l PATENTEL 1 01974 SHEEI 2 OF 2 1 ALARM SYSTEM WITH AUTOMATIC RINGBACK BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a centrally monitored remote alarm system and more particularly to an automatic ringback system for centrally monitored remote alarm'systems.

2. Descriptionof Prior Art .In the field of centrally monitored alarm systems, a plurality of remote locations are monitored at a central location. At the remote location, there usually are a plurality of switches connected to various devices to be protected including a first group for day-time monitoring and a second group .(including part of the first group) for night-time monitoring. A selection switch is included at the remote location to connect the central office with either the group of day-time or the group of night-time switches at the remote location.

In the evening, a large number of stores in a given area close at approximately the same time; i.e., 6:00 or 9:00 in the evening. At this time, the remote systems are switched from day-time monitoring to night-timing monitoring and the central office must indicate by a ringback signal that the central office has received the change from day to night monitoring and that the system appears in order and consequently the client may leave the premises.

In the prior art devices, the operator at the central location must ring back each received signal manually. Consequently, the client must sometimes wait 2-3 minutes or sometimes as long as 10 minutes for the busy operator to ring back the received signal. To alleviate this inconvenience to the client, some companies have provided additional personnel at these peak hours. The

additional personnel required is unnecessary expense which is passed on to the client.

SUMMARY OF THE INVENTION The present invention overcomes the shortcomings of the prior art previously discussed by providing an automatic ringback system wherein the central office senses the changing from day to night monitoring at the remote location and automatically transmits a ringback signal to indicate that the change has been received and noted and that the alarm system is in operating order. A ringback signal is transmitted repeatedly for a given number of times. Upon the termination of the ringback signal, the client may leave the premises knowing that the central location has received the day to night change. At the central location, an indicator is activated for each client to which a ringback signal has been transmitted and is extinguished only by resetting of the central monitoring unit and switching the central monitoring unit from day to night monitoring. The central unit contains a single DC power source. for use with a plurality of monitoring circuits and a single AC generator for transmitting the ringback signal to the plurality of remote units.

OBJECTS OF THE INVENTION An object of the present invention is to provide an I automatic ringback system.

Another object is to provide a simple and inexpensive ringback system for alarms.

A further object of the invention is the provision of a single power source and a single ringback signal generator for use with a plurality of zone monitoring remote site alarm systems.

Another object is to provide an automatic ringback which is easily incorporated into a present alarm system without major modification.

Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawmgs.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the overall system including schematics of the central power system and the remote site switches;

FIG. 2 is a detailed schematic of the individual zone monitoring units with automatic ringback capability.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows, in block diagram form, a central office having a central power. supply unit 10 and individual zone monitoring units 11, 12 and 13 and remote locations 14, 15 and 16 connected respectively to zone monitoring units. The central power supply 10 has a DC source 17 having one side connected to ground 18 which is connected to output terminal T1. Connected to the other side of DC source 17 is lamp 19 which is also connected to terminal 20 of relay 21. Relay 21 includes a solenoid 22 having one side thereof connected to the terminal 22 and the other side connected to ground 23. Also connected to ground'23 are the two ganged switch elements 24 and 25 of relay 21. Switch element 25 connects terminal 20 to ground 23 and switch element 24 connects terminal 26 to ground 23. Connected to terminal 26 is a bell 27 which is connected to a 20-cycle motor generator set 28 which is also connected to ground 29. The ungrounded side of motor and generator set 28 is connected to terminal T3. The negative side of the DC power source 17 is connected to terminal T4.

Upon activation of relay 21, solenoid 22 closes the switch elements 24 and 25 to contacts 26 and 20, respectively, connecting light 19 with the DC source 17 and bell 27 with the AC signal from motor generator set 28.

Connected to the terminals T1-T4 of central power supply are terminals TAl-TA4, terminals TBl-TB4, and TCl-TC4, respectively of zone monitoring units 11, 12 and 13, respectively. Though showing only three units, the number of units may be increased and is limited only by the capacity of the central power supply system. The lamp 19, bell 27 and the 20-cycle motor generator 28 are examples of devices which may be used. Consequently any equivalent indicating and AC signal generating device may be used.

Connected to terminals TAS, TBS and TC6 are remote site units l4, l5 and 16, respectively. A simplified schematic of the remote site unit is shown at remote site 14. Generally, the remote site has a day-night switch 30 having a day terminal 31 with day switches 31A, 31B and day resistor 31R connected in series to ground. A second terminal 32 is a night terminal having night switches 32A, 32B and night resistor 32R connected in series to ground. Also in the remote unit is a ringback indicator 33 connected between the input line and ground. Devices 31A, 31B, 32A and 32B may be either normally open or normally closed switches which may be foil on windows, switches on doors, windows, safes and any device which is to be monitored during the day or night position of switch 30. If they are normally open switches, they are usually in parallel with the resistor so that the system can be monitored, whereas if they are normally closed switches, no resistors are needed. The individual resistors 31 and 32 are of different values such that the control monitoring system 11 can sense which mode switch 30 is in.

As will be discussed more fully in the explanation of FIG. 2, upon moving switch 30 from the day position 31 to the night position 32, central zone monitoring unit 11 will sense the change and automatically transmit back a signal from AC ringback signal generator 28 to activate ringback indicator 33 in the remote location. Also, upon sensing the changing of the position of switch 31, relay 21 is activated which in turn activates lamp 19 and bell 27 until reset by a central operator.

A detailed schematic of the zone monitoring unit 11 is shown in Hg. 2 and has terminals TAl-TA4 connected respectively to terminals T1-T4 of the central power supply and terminal TA-5 connected to the remote site unit 14. TAl and TA2 are connected to three position toggle switch 40 at switcharms 41 and 42, respectively. Switcharms 41, 42 and 43 are ganged by a restoring spring 44, and are shown in their neutral position resting on contacts 46, 48 and 49, respectively. In the reset position, the switcharms are moved up, arm

41 coming in contact with contact 45, 42 coming in contact with 47 and 43 breaking contact with contact 49. For the test position, the switch is moved down and switcharm 41 breaks contact with contact 46, 42 breaks contact with contact 48, and 43 comes into contact with contact 50, which iis connected to terminal TA-3. Terminal TA-l is also connected through resistors 51 and Zener diode 52 to terminal TA-4 and provides current regulation for the zone monitoring network.

Connected in parallel between contact 46 and terminal TA4 are two series circuits having lights 53 and 54, resistors 55 and 56, and silicon control diodes (SCR) 57 and 58, respectively. Connected in parallel with lights 53 and S4 and series resistors 55 and 56 are resistors 59 and 60, respectively. Upon detection of a break 63 and 64 are connected to the output of transistors 71 which has capacitor 72 at its base and biasing resistors 73, 74 and 75. Transistor 71 amplifies a signal obtained I i by a variable voltage divider formed by resistor 76 and a movable tap.

The voltage across voltage dividing resistor 76 is determined by the resistance between 76 and the remote site. The resistance between the remote location and the central office may change due to opening of one of the switches in the remote site, breaking of a line between the remote site and central location and a short between the remote site and central location. The resistance between 76 and remote site may be changed also by varying the position of switch 77 having contact arms 78, 79, 80 and 81 and positions A, B, C and D. When the four ganged contact arms 78, 79, 80 and 81 of switch 77 are in the A position, the alarm system is in the night monitoring position. When the contact arms are in the B position, the alarm system is in the day monitoring position. When the contact arms are in the C position, the alarm system will simulate an opening condition to test the zone monitoring electronics, including SCR 57 and indicator light 53. When the contact arms are in the D position, the alarm system will simulate a grounding condition to test the electronics, including SCR 58 and indicator light 54.

The resistance from the remote location is connected to contact arm 78. In the day-time position, 78 is connected directly to resistor 82 which is connected to parallel combination of voltage dividing resistors 76 and capacitor 83. In the B, C and D positions of contact arms 78, resistor 84 is connected in series with resistor 82. Contact arm 79 is open in the A and B position and in the C position, connects variable resistor 85 in parallel with a series combination of resistors 82, 84 and capacitor 83. Resistance 85 is chosen to be large enough so as to simulate a break or open circuit condition. In the D position, contact arm 79 connects resistor 86 between resistors 75 and 82 and is chosen so as to simulate a grounded condition. Connected in series between contact 49 and terminal TA4 of switch 44 are variable resistor 87, meter 88, resistor 89 and parallel capacitor 90. Connected between meter 88 and resistor 89 is contact arm 78 of switch 77. In the neutral position of switch 40, contact arm 43 connects the resistance of the remote site via terminal TA5 with meter 88 via contact 49. The condition of the remote site is not only monitored by meter 88 but by the electronics including SCRs 57 and 58 and indicators 53 and 54.

Connected to contact 46 of switch is relay coil 90 having contact arms 91 and 92. In parallel with relay coil is capacitor 93 which, as will be described later, provides a slow release of the relay. The parallel combination of capacitor 93 and relay coil 90 is connected to variable resistor 94 which is connected to switch contact 95. When relay coil 90 is activated, it will break its circuit with the power supply by moving contact 92 out of engagement with contact 95 and into engagement with open contact 96, but will retain contact arms 91 and 92 in their down position for a time to be determined by the values of the capacitor 93 and the relay coil 90. Contact 97 for contact arm 91 is connected to positions B, C and D of contact arm 81 of switch 77 and contact 98 is connected to switch arm 43 of switch 40. Contact arm 81 of switch 77 is connected to contact 50 of switch 40 and terminal TA3 and has its A position open and its B, C and D positions connected to contact 97. It should be noted that contact arm 80 of switch 77 has all four of its positions open and is not connected in the circuit.

Connecting contact arm 92 to the anode of SCR 57 is the parallel combination of capacitor 99 and resistor 100 and series resistor 101. Though capacitor 99 and resistors 100, 101 are shown between SCR 57 and contact arm 92, 92 and 57 may be directly connected and the capacitor 99 and resistors 100 and 101 may be connected in series with the parallel combination of relay coil 90 and capacitor 93. As will be described more fully hereafter capacitor 99 and resistors 100, 101 provide a cycle limiting function to limit the number of cycles relay coil 90 opens and closes gang contact arms 91 and 92.

The anodes of SCRs'57 and 58 are connected to terminal TA2 through switch arm 42 and contact 48 by diodes 102 and 103, respectively. Diode 103 prevents the ignition of light 54 upon the activation of SCR 57 and diode 102 prevents the ignition of light 53 upon the activation of SCR 58.

Since the alarm circuitry alone is not part of the present invention, only the operation of the automatic ringback system will be described in detail. Initially, the system is in the day monitoring condition wherein said switch 77has contact arms 78, 79, 80 and 81 in their B position. Switch 40 which has switch arms 41, 42 and 43 in'their neutral position contacting contact 46, 48 and 49, respectively. Relay coil 90 is deactivated with contact arm 91 contacting contact 98 and contact arm 92 contacting contact 95. With the switches in the position just described, the remote site is being monitored via terminal TA5, contact arm 91, contact 98, switch arm 43, contact 49, meter 88, contact arm 78 to the monitoring electronics. When the client at the remote site desires to leave his premises and switches his daynight switch to the night-time position, the monitoring electronics sense a' break in the system and activates SCR 57. Upon activation of SCR 57, a series circuit is created from the DC source 17 through terminals T4 and TA4, SCR 57, diode 102, contact 48, switch arm 42, terminalTAZ, terminal T2 to relay coil 22 to activate indicator light 19 and bell 27. Also connected to the DC power source 17 through SCR 57 is break indicator 53 via contact 46, switch arm 41, terminal TAl, and terminal T1, and relay coil 90 via resistors 101, 100, capacitor 99, contact arm 92, contact 95, resistor 94, contact 46, switch arm 41, terminal TA] and terminal TA2. Thus, on switching the remote site switch from the day to night position, SCR 57 is activated and activates relay coil 22 and its indicators 19 and 27; indicating light 53, and relay coil 90.

Upon the activation of relay coil 90, contact arms 91 and 92 are moved to their down position. With contact arm 91 in contact with contact 97, and AC signal from motor generator set 28 is transmitted to the remote location to ring remote indicator buzzer 33 through terminals T3 and TA3, the switch contact arm 81, position B, contact 97, contact arm 91, and terminal TA5. When contact arm 92 moves out of engagement with contact 95, the DC power supply is removed from relay coil 90 and it starts to discharge through capacitor 93. Capacitor 93 prevents relay coil 90 from immediately discharging and consequently holds contact arms 91 and 92 in the down position for a preset amount of time, thus producing more than momentary buzzing of remote indicator 33. Also, upon the breaking of contact between contact arm 92 and contact 9, the charging circuit for capacitor 99 was broken and a small amount of charge is bled off during this break by resistor 100. With the energy in relay coil 90 being diss'ipated, contact arms 91 and 92'resume their upward position, cutting off the AC signal through terminal TAS and reactivating the charging circuit of the capacitor 99 and relay coil 90. The cycle is then repeated as 1 just described.

The number of times the cycle will be repeated so as to allow the contact arms 91 and 92 to move up and down is determined by the resistors 101, 100, 94 and capacitor 99. At some point in time, capacitor 99 will be charged to a voltage sufficient to prevent the activation of coil 90. At this point, a majority of the DC voltage will be across capacitor 99, relay coil 90 will be deactivated, and the contact arm 91 and 92 will be in their up position, disconnecting the AC signal from terminal TA5.

Since the remote condition sensing device is an SCR, SCR 57 will remain conducting once gated until reset. Thus, break-light 53 will be ignited and the operator will know which remote sites have been changed from night today monitoring. When the operator has time, he will move switch 40 into its reset position, breaking the series circuit of SCR 57 with the DC power source 17 and thus deactivate the SCR 57. At the same time, the operator moves switch 77 into position A for night monitoring.

Thus, the circuits as just described automatically transmit a ringback signal to the remote site to indicate that the central office has sensed the change of position of the remote site switch from night to day monitoring and automatically transmits an AC signal for a given number of cycles. When the operator has time, he resets the central office and turns the central office from day to night monitoring'of the remote site. Thus the present invention has provided an automatic ringback system which will allow the client to leave his premises knowing that his system is in operation without the necessity of manual manipulation by an operator in the central location.

Though the various indicators have been shown as lights, bells or buzzers, the power sources have been shown as a DC battery and a 20-cycle motor generator set, any substitution of equivalent elements can be made without deviating from the spirit or scope of the invention. The present automatic ringback system has been described in combination with a specific alarm system but may be used with any other type of alarm system. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the invention being limited only by the terms of the appended claims.

What is claimed is:

1. An alarm system with automatic ringback from a central location to a remote site comprising:

a manually operated remote switch at said remote site connected to said central location;

a remote indicator at said remote site connected to said central location;

a switching means at said central location having a first terminal connected to said remote indicator and a second terminal connected to a signal source;

a sensing means at said central location connected to said remote switch for sensing the condition of said remote switch; and

a switch control means at said central location connected to said sensing means for interconnecting said switching means first and second terminals for a limited time in response to a first sensed condition;

whereby said remote indicator is activated 'by said signal source for said limited time.

2. An alarm system as in claim 1 including a first central indicator connected to said sensing means and activated in response to said first sensed condition until manually reset.

3. An alarm systemas in claim 1 wherein said switch first and second terminals.

5. An alarm system as in claim 4 including a time delay means connected to said relay means for delaying the activation of said relay means upon opening of said relay switch.

I 6. An alarm system as in claim 3 including a cycle limiting means connected to said cycling means for disabling said cycling means at the expiration of said limited time.

7. An alarm system as in claim 6 wherein said cycle limiting means comprises a resistor-capacitor circuit whose rate of change determines said limited time. 1

8. An alarm system as in claim 1 wherein said manually operable remote switch has a day and night condition and said first sensed condition being said night ing means, and a third terminal connected to said ringback signal source for automatically interconnecting said first and third terminals for a fixed du ration in response to a sensed night position.

10. An alarm system as in claim 9 wherein said switching means includes a relay means connected to said sensing means for interconnecting said first terminal and said second terminal or interconnecting said first terminal and said third terminal.

11. An alarm system as in claim 10 wherein said sensing means is a bistable means'which remains activated upon sensing said night position until manually reset.

12. An alarm system as in claim 11 wherein said relay means includes a switch connected in series with said relay means, said relay upon activation simultaneously opening said series switch and interconnecting said 7 switch means first and third terminals.

13. An alarm system as in claim 12 including a capacitor in parallel with said relay to delay deactivation of said relay upon opening of said series switch.

14. An alarm system as in claim 12 including an RC circuit in series with said relay whose rate of charge determines the fixed duration.

15. An alarm system as in claim 11 including a first indicator connected to said sensing means; and manual reset means for resetting said sensing means, and said first indicator, and for discharging said RC circuit.

16 An alarm system as in claim 15 including a manual switch connected between said ringback signal source and said third terminal.

17. An alarm system as in claim 2 wherein there is a I corresponding plurality of remote switches, remote indicators, switching means, sensing means, switch control means, and first central indicator; a single signal source connected to said second terminal of each switching means, and a single second central indicator connected to each of said sensing means.

18. An alarm system as in claim 17 wherein said single signal source is an alternating current and includes a single direct current source connected to each of said

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
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US3069673 *Mar 18, 1959Dec 18, 1962Westinghouse Electric CorpRemotely controlled alarm system
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3991412 *Feb 14, 1975Nov 9, 1976Arne Verner HillbergMulti-subscriber alarm system with central receiving and transmitting installation
US4012727 *May 21, 1975Mar 15, 1977General Signal CorporationAlarm control system
US4282517 *Jan 25, 1979Aug 4, 1981Potter Electric Signal CompanyAutomatic ringback for direct current monitoring system
US4777488 *May 16, 1986Oct 11, 1988Cw Products, Inc.Restaurant service request communications system
Classifications
U.S. Classification340/502, 340/550, 340/517, 340/504
International ClassificationG08B25/01
Cooperative ClassificationG08B25/014
European ClassificationG08B25/01C