CA1047605A - Security system - Google Patents

Abstract

ABSTRACT

A security alarm system for selectively detecting and signalling abnormal or emergency conditions, such as robbery, assault, fire, smoke, burglary, medical emergencies, etc. in a home, apartment, institution, plant or other place of business via digitally-coded messages, to a central data station. This central station monitors or service a plurality of areas to be guarded or protected and manually or automatically directs or dispatches appropriate aid to the location or area from which the signal originated. Essentially, the system comprises sensors responsive to the occurrence of abnormal or emergency conditions which transmit digitally-coded messages including information on self-identification and the nature of the emergency to a line converter. The line converter decodes the signal and then adds on information identifying its own location (e.g., room number, apartment number), and synthesizes a combined digital message which is then transmitted along power lines, such as the 110 Volt or 220 Volt AC power circuits commonly used in homes, apartments, businesses and institutions, at transmission fre-quencies and voltages substantially different from the power frequency and voltage, to a master controller. The master con-troller receives and decodes the digitally-coded messages trans-mitted by the line converters and adds further location information (e.g., street address) and synthesizes an appropriate digitally-coded message which it communicates to one or more central stations using one or more of a variety of transmission media:
telephone line, coaxial cable, radio and external power line.
Each central station services a plurality of master controllers in different protected areas.

Description

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Present day trends toward massed housing in communities ~;
and high-rise apartment complexes as well as wide spread changes in socio-economic conditions afecting the aged, infirm, or sick have accentuated the desirability, need and importance of effec-tive security systems capable of effecting an alarm and/or a response to a siynal by police, fire bureau, medical or ambulance service to provide aid and assistance to pexsons involved in an emergency situation.
Similarly, there is an increasing present-day need in institutions, such as schools and hospitals, and in industrial plants, depaxtment stores, and other places of business, for ; security protective systems which provide a prompt response and assistance to meet the emergency requirement of any particu-lar situation, be it robbery t assault, burglary, fire, sickness ; or injury to persons.
We are aware of prior art patents relating to this subject. For example, U.S. Patent 3,601,540, issued August 24, 1971 discloses a security system useful in the home and in - commercial structures whereby to provide warning against impend-ing danger, such as intruders, fire, etc. The patent discloses circuitry whereby the alarm means may include automatic tele-; phone diallng of a predetermined number, such as the nearest fire station or police station, to deliver a voice message.
We are also aware of a more recently issued U.S. patent, U.S.
Patent 3,694,579, dated September 26, 1972, ~Ihich describes an -emergency reporting digital communications system ~7hereby a ; selectively activated encoder-transmitter communicates data via a computer relay receiver to a data center where an oper-ator reads the computer output and dispatches necess2lry assist-ance in response to the particulax emergency decoded dispatch.
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Both of these patents are~limited in their usefulness and are not adapted to provide the necessary scope, reliability and supervision or monitoring re~uired ~or a security system suited, for example, to a massed housing situation or to an institutional application.
It is an object, therefore, o~ our invention to provide a security system, involving digital communication networks, whereby a master controller services a large number o~ locations, such as rooms in a home or institution, or apartme~ts in an apartment complex, and by a reliable communication medium, such as a telephone line, delivers a suitable message to a central station, where personnel are constantly on duty to see to the dispatch of the re~uired assistance to the appropriate loca-tion. It is,moreover, an object of our invention to provide automatic supervision by the master controller of the line converters at the various locations and also of the intervening circuitry.
We provide a security system comprising essen-tially five types o~ components, comprising (a) ensors actuated manually or responsive to conditions, which initiate trans-mission of digitally-coded messages to ~b) a line converter which adds its own digital code to the digitally-coded data received from the sensors to provide a synthesized digital message communicated via a power line such as the usual 110 or 220 Volt, 60 or 50 cycle, AC house wiring, to a (c) remote input or output device such as a remote intelligence siren, and to a (d) master controller which receives all signals, ; stores them, processes them, adds its own digital codes, and locally triggers an alarm while communicating via an appropriate communication media (e.g., telephone line~ coaxial cable. radio, `

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external power lins) with (e) a remote central station.
The message transmitted by an active sensor includes complete identification of its location and nature o the emergency, thereby inferentially serving to advise the nature of assistance required. The sensors are o:f the fixed location .
type activated automatically (as by openin~ a door or window) or of the mobile type activated voluntarily by the person wear-ing or carrying the sensor. The counterpart line convexter which receives messages from a sensor first stores i-t and then adds on its own digital code identifying its own location, which may be a specific room in a home, a room in an institu- -~
tion, or a specific apartment within an apartment complex.
The digital message transmitted by a line converter is in the :-~
form of a coded electrical signal of much lower voltaye and much higher frequency than that carried in usual power circuits within the securiky area, for example, 110 or 220 Volts at 60 or 50 cycles.
We further provide supervisory circuitry which enables a master controller to determine the status of the line converters connected to the powex lines, that is, whether any of them have been activated or not, and whether any of the devices are malfunctioning or are disconnected from the power line.
We further provide alternate circuitry wherein the sensors are of various types, such as the direct-wired type, the radio frequency (RF) type or ultrasonic (US) type. The RF and the US types communicate with their counterpart line :. ~
converters by radio fre~uency or by ultrasonic waves, respect : ~.
ively. ~. -A preferred embodiment of our invention will be more ; :.
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fully described hereinater, along with variations thereof, in connection with the accompanying drawings, wherein:
Fi~ure 1 depicts in diagramma-tic block form one form :.
of the security system embodying our invention using a direct- .
wired link to the line converter;
; Figure 2 shows a preferred variation of the em~odi-ment of Figure 1 employing a radio frequency type sensor; . ~. :
Figure 3 shows a further variation of the embodiment of Figure 1 employing an ultrasonic ~ype o-f sensor;
Figure 4 shows a preferred variation of the embodi ment of Figure 1, wherein the master controller and the central station communicate via radio transmission media;
Figure 5 shows a further variation of the embodiment of Figure 1, wherein the master controller and the central station communicate via a telephone network or coax:ial cable, such as one channel of a television coaxial cable, using ei-ther leased voice-grade lines or regular switched lines;
Figure 6 shows in diagrammatic block form a prefexred embodiment of security system for an individual home or apart- ..
ment;
Figure 7 shows in diagrammatic block ~orm the func-tional specif:ics of a sensor, whether of the RF, ultrasonic or direct wire type, including a digital encoder;
Figure 8 shows in diagrammatic block form a preferred .::
form of digital encoder for use in the sensor of Figure 7;
Figure 9 show~s the speci.fic circuitry for a preferred .
embodiment of the transmitter of the RF sensor type shown in : Figure 7; ::~
Figure 10 shows the specific circuitry for a pre-~erred embodiment of the transmitter of the u].trasonic (US) ::

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sensor type shown in Figure 7;
Figure 11 shows in diagramma-tic block form the details of an embodiment of RF line converter in Figure 2;
Figure 12 shows, fragmentally, a line converter (direct wire) variation of the line converter of Figure 11, suited for directly wired input;
Figure 13 shows, fragmentally, a variation of Figure 11, an embodiment of the ultrasonic line converter of Figure 3, used with a sensor of the ultrasonic type;
Figure 14 shows in diagrammatic block -Eorm the specific circuitry of an embodiment of the digitc~l processor employed in the line converter embodiment shown in Figure 11;
E'igure 15 shows diayrammatically the format of the data transmitted by the digital processor shown in Figure 14;
Figure 16 shows ~e specific circuitry for the digital data averager and memory section in the digital processor of : Figure 14;
Figure 17 shows in diagrammatic block form a simpli : .
fied variation of the line converter of Figure 11, suited to ultrasonic (US) transmission from the sensor;
Figure 18 and 18A show alternative embodiments of circuitry whereby a line converter (of direct wire, RF, or US
types) using the po~er line external to the security area as a communication medium can be partially supervised by the ~:~
master controller;
Figure 19 shows an embodiment of the circuitry where-by full supervision of line converters (of direct wire, RF or US types) may be obtained;
Figure 20 shows the timing diagram for the RF pulses generatecl by the supervisory circuit of Fiyure 19, in response : 5.

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6~5 to RF supervisory signals fromthe master controller;
Figure 21 shows in diagrammatic block form the func-tional specifics of the master controller in the embodiment of Figure l; .!: ,.. :.. ''., Figure 22 shows an embodiment of the circuitry used in the master controller of Figure 21 for the full supervision :-of the line converters and the power lines, utili~ing time-division multiplexing; and Figure 23 shows in diagrammatic bloc~ form the speci-fics of the equipment provided in the central station of theembodiment of security system shown in Figure 1.
Referring to the drawings, particularly F:igures 1-5, there is shown therein a security system embodying ol1r inven-tion, and variations thereof. In Figure 1, a general security . area 10 is shown, which may be a home, an apartment, an insti-tution, an industrial plant, or other place of business. The .
system comprises a number of components within the security . .:
area, namely detectors 11, line converter 12, and master con- . .

troller 13. Outside the security area are located a remote 20 control device 14 (such as a siren) and a central station 15. .~.
If desired, device 1~ may be located within the security area.
In Figure 2, a modification of the embodiment in ~. Figure 1 comprises a sensor 16 of the radio frequency type :
-.~ which communicates via electromagnetic waves with its counter-part line converter 12a. Similarly, in Figure 3 a further modification of the embodiment of Figure 1 comprises an ultra- ~
sonic sensor 17 which communicates via ultrasonic waves with ::
its counterpart line converter 12b. :-Referring again to ~igure 1, the master controller 13 comprises a line receiver 18, a controller digital processor 19, ''; ': '.
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an alarm device 20 of the visual and/or audible type, and a communicator 21 for transmitting signals via a communication link 22, which may be a telephone line, coaxial cable, radio~
~requency link, high-voltage power line, direct cable or other, to the central station 15.
The central station 15 comprises a communicator 23 for receiving signals from the communicator 21 of the master controller, a central station digital processor 24, an internal alarm device 25 including visual and audible elements, and an external alarm device 26 including visual and audible elements.
Referring to Figures 1, 2 and 3, the detectors 11 are simply electrical switches such as magnetic switches, micro switches, slide switches, temperature-sensitive switches or smoke-sensitve switches. The switches may be of the normally-open or normally-closed type. They may be actuated manually, triggered by a person in distress, or they may respond auto- ;
matically to a change in conditions such as the opening of a door, or change in pressure or temperature, smoke and the like.
These detectors may either provide an input signal directly (i.e., direct-wire? to the line converter 12, as in Figure 1, or through the intermediary of a sensor as in Figures 2 and 3.
As will be explained more fully hereinafter by reference to Figure 7, the sensor (16, 17) comprises a digital encoder 27 and a transmitter 2~ of either the radio frequency (RF) or - ultrasonic (US) type for signalling the counterpart line con-verter. The digitally coded signals originating at a sensor are received and interpreted by the counterpart line converter.
As more fully explained later, the line conver-ter 12a or 12b combines its own digital code with the digitally coded informa-tion received from the sensor and then transmits the synthesi~ed :

digital signal via the power-line system 29 to the line receiver 18 of the master controller.
The coded signal from a sensor identifies the partic ular sensor activated and the type of emergency (e.g., personal attack, medical emergency, robbery, burglary, fire). The line converter code added to the signal transmitted to the master controller identifies the location and status of the particular line converter activated.
The master controller 13 is one common receiving unit within any security area. The security area may be a home, an apartment complex, an institution such as a school, hospital or prison, or a business or commercial establishment, such as a department store, a warehouse, or a shop.
As will be noted from Figures 1, 2 and 3, a plurality of detectors 11 in different locations tranSTnit a signal to a ;;
common line converter 12, 12a, or 12b. Also, any number of -~
additional line converters Inot shown) may feed into the master controller 13 via the power-line system 29. Additional details concerning the component parts of the sensors 16 ancl 17 and of the line converters 12, ]2a and 12b will be described ~
later on in connection with Figures 7 through 16. As will be ~ ;
explained in more detail later in connection with Figure 21, the master controller 13 receives all signals from the line converters, stores them, processes them, adds its own digital codes and takes action of two kinds~ Locally, it triggers the alarm 20 ~hich gives visual and/or audible indication of the nature of the emergency, its location, and the person or ~-property threatened. Also, the master controller communicates with the remote central station 15 using any one of several communication media of which Figure 1 shows coaxial cable or ~L7~
direct wire 22, Figure 4 shows radio, and Figure 5 shows a telephone network. If desired, a high-voltage external power-line system may be employed also. The master controller 13 sends digitally coded messages to the central station 15 which - include the information received from active line converters 12 (or 12a, 12b) as well as self-identification code providing information as to the location and nature of the emergency and a status message as to the operational and functional status of the various system components.
It will be understood that a single central station 15 services a large number of master controllers. Thus, there may be one central station 15 for an apartment complex in which there is one master controller 13 for each apartment. ~lterna-tively, a sinyle central station 15 ma~ service an entire area or region in which individual security systems are provided for a number of homes or apartment buildings.
In Figure 6 is depicted a security system for a typical home installation. The similarity of components to those of Figure 1 will be apparent. It will be noted that radio frequency type sensors 16 and line converters 12a are employed. If desired, ultrasonic type sensors 17 and line converters 12b may be employecl, or direct-wire line converters 12. Also, the master controller 13a communicates with the central station 15a via the switched telephone network 22a ~-~
similar to that of Figure 5. The communicator 21a of the -master controller 13a in Figure 6 includes a digital dialer which is pre-proyrammed to automatically dial the telephone numbers associa~ed with the central station 15a~ ~he master c~ntroller 13a activates a local alarm 20a which provides audible/visual alarms with different alarm patterns for ~ 9 '', ~'.' . ~' .,.' ' .. . . ... . . . . . . .

7~¢~5 different emergencies. This provides immediate local identi-fication of the emQrgency and information as to the type of assistance required.
It should be understood that the alternate embodiments of security systems shown in Figures 4 and 5 differ from that shown in Figure 1 merely in the type of communication medium employed between the master controller and the central station.
Accordingly, the master controller, the central station and components thereof in Figures 4 and 5 are designated by the same reference numerals, as in Figure 1 except for the addition of the suffix letter "a" and suffix letter "b". ~
Referring now to Figures 7-16 inclusive, additional -details of the sensors and line converters will be described.
As shown generally in Figure 7, -the siynaL input to the diyital encoder 27 of the sensor is provided by one or more detectors 11, represented by a normally-open electric switch lla, though if desired, a normally-closed switch may be employed.
A change in the state of the switch lla may be effected manually or automatically in response to a change of conditions (e.y., pressure, heat, smoke, etc.). The details of one embodiment of the digital encoder 27 are shown in block form in Figure 8.
In this figure, a ~atiny latch 30 stores input information upon sensor actuation and turns on the voltaye-controlled oscilla-tor 31, bit width counter 32, address counter 33 and timer counter 34. The voltage-controlled oscillator 31 determines the subcarrier requency and its frequency is controlled by the data output from the read only-memory element 35. The bit width counter 32 determines the number of waves of subcarrier for one data bit length. ~ messaye . ~.
consists of a fi~ed number of sequential data bits. The 10. ::

~17~i~5 address counter 33 sequentially selects data bits from the read only-memory element 35 or from external data (e.g., type of emergency -- depending on ~he alternative means of actua-tion). Timer counter 34 determines the number of messages to be transmitted, and upon entering the end of transmission resets the gating latch 30 which in turn resets the entire circui~.
Figure 9 shows the details of one embodiment of the frequency modulated RF transmitter 2g of Figure 7. In Figure 9, the transistor 36 and its associated parts form an ~
oscillator. Inductor 37 and capacitors 38, 39, and 40 determine the frequency of the oscillations. Current through transistor 36 can be gated on or o~f by transistor ~1 and hence, an enable input to transistor ~1 can be used to gate the oscillator on or of~. ~pplying the siynal to subcarrier input at ~2 modulates the oscillator.
In Fîgure 10, the details of an embodiment o~ the alternative ultrasonic transmitter of Figure 7 are shown. In this figure, logic gates 43 and 44 form a low power oscillator whose frequency is determined by resistor 45 and capacitor 46 and to a large extent by the natural resonance frequency of the bimorph ultrasonic transducer ~7. Driving the enable input ~8 low turns the oscillator on, while driving it high -turns the oscillator off. A subcarrier signal applied to input ~9 both ~requency modulates and amplitude modulates the output signal from the transducer ~7.
Figure 11 shows in block diagram form a preferred embodiment of the line converter 12a of Figure 2. The signal transmitted by RF sensor 16 is received by an RF receiver-demodulator 51. Figure 12 shows a block diagram variation of Figure 11 wherein the input signal is over a direct wire rather 11. ,.. , :,. :

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than via an RF sensor~ Figure 13 shows a block diagram varia-tion of Figure 11, wherein an ultrasonic receiver-demolulator 51a is provided.
In any ~vent the input signal is transmitted directly or through RF receiver-demodulator 51 or through ultrasonic -receiver-demodulator 51a to a digital processor 52. The output signal of the receivers 51, 51a is an encoded subcarrier. The digital processor 52 decodes this subcarrier and recovers the :
digital messages received. These messages are stored in a memory, as more fully described in connection with Figure 14, until they are ready for a retransmission. RF detector 53 detects the presence of transmission from other line converters.
If the power line (29) is clear of a transmission signal, time delay element 54 is actuated and after a predeterminecl time delay, RF generator ancl modulator 55 is activated sending a signal to the RF ampliier 56 which in turn transmits an RF
signal along the power line (29) system. Isolatox 57 isolates the power current from the radio-frequency circuits. As shown, the digital data from the digital processor 52 modulates a sub-carrier signal generated in the subcarrier yenerator and modu-lator 58, and the modulated subcarrier signal then modulates the RF siyllal generated in the RF generator and modulator 55.
The digital message is sent repeatedly and continuously for a predetermined time unless a request for extension (received from the mas~er controller) is sensed by the RF detector 59.
Figure 14 shows, in block diagram form, a more de-tailed circuitry for the digital processor 52 of Figure 11.
The subcarrier input signal received from the RF demodulator 51 is detected and demodulated by the subcarrier demodulator 60 which gives data output, write clock and subcarrier detect 12.
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signals. If a subcarrier is detected, monostable element 62 is triggered producing positive voltage output for a period sufficient to trigger gate 63 which in turn puts the digital data averager 64 in "write" mode. During this period, the data produced by the subcarrier demodulator 60 are averaged and stored and partially decoded. At the end of the "write"
period, flip-flop 65 is set and prevents gate 63 from being enabled by subsequent incoming subcarrier signals, thus preserving the data stored in data averager and memory 64 until signal processing is complete. The disabling of gate 63 puts data averager and memory 64 in-to a "read" mode during which the stored data are transmitted into data selector 66.
Simultaneously, the digital data averager 6~ also ~etects for the presence of word synchroni2ing bits. ~he speed of the data transmission is determined by output o the read clock generator 67 which is also used to drive the 6-bit address counter 68. This counter selects data from a read only-memory (ROM) and status register 69. Synchronizing pulses from digital data averager and memory 64 puts the data transmission from ROM and status register 69 in the proper sequence relative to the data output from digital data averager and memory 64. Data selector 66 alter~ately selects either the data output from the digital data averager and memory 64 tsensor/actuator identification and status codes) or from ROM and status register 69 (line relay receiver identification and status codes) to be transmitted out into the communicator. The format of the data transmitted out ~rom the line converter is shown in i`
Figure 15.
Gate 70 i5 turned on by the presence of a transmission siynal from another line relay receiver. In the absence of 13.

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such a signal and when flip-flop 65 is activated, gate 71 is enabled and in turn triggers monostable 72 to start a delay pulse. At the end of the time delay, flip~flop ?3 is triggered sending an enabling signal to the RF transmitter. At the same timel gate 74 is readied to receive a reset co~.and from the master controller receiver 18. When a reset command is sent, flip-flop;65 and 73 and other modules are reset. If gate 70 detects the presence of a transmission from another line relay receiver, gate 71 is inhibi-ted, preventing the line relay re-ceiver from transmitting until the line is clear of transmission.
In Figure 16 is shown an embodiment of the circuitryembodied in the data averager and memory element 6~ of the dig-ital processor of Fiyure 14, adapted for processiny 32-bit worcl messages. If desired, messages of other lengths may be employed.
During a "wxite" mode, clock selector 76 selects the write clock to be used for syndromes by processing the digital data. These data enter via terminal 77 through gate 78 into one of the inputs of a 6-bit binary adder 79. At this time, gate array 80 inhibits input into the B-inputs, collectively ,: .
identified by reference nurnber 81, of the adder 79. All these ,:....:
inputs are set to zero. The A-inputs collectively identified by the reference numbers 82, of adder 79 are connected -to the date output of a 6 x 32^bit shift register array 83. Also at this time multiplexer 84 connects the sum outputs 85 of adder 79 into the data inputs of shift register array 83. The adder ;~
outputs 85 shows the binary sum of the stored data bi~s and ~he incoming data bit from 77. If 1 is the cell member in each element of the shift register 83, (i = 0, 1, . . . . 31) and ~ is the number of messages (words) written into the memory then the binary value of the sum output 85 will be: xi - ni, 14.

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where ni represents the number of ones of bit l that appear during N number of messages.
Counters 86 and 87 record the number of messages N
accepted by the digital averager and memory.
During the read cycle, gate 78 is inhibited, pre-venting incoming data from being written, and gate array 80 is enabled, connecting the adder inputs 81 to the output of the 7-bit counter 87. The binary number represented by the inputs 81 is 63 -(~).
At the same time multiplexer 84 is selected as to feed the outputs of shift register array 83 into its inputs, thereby continuously recirculating the data. The numher represented by the outputs 85 and 88, Si, is the sum of the adder inputs 82 and 81 and may be expressed thusly:

Si = 63 ~ 2 ~ ni- ~

If ni> ~ or ni - N ~ l, then Si ~ 64. ~ ~;

; Thus, for a given bit cell, if the number of ones ~
appear more than half of the number of messager (majority = one) ~ ;
then the carry output 88 will be one. On the other hand, if the majority of the bits for a given cell bit .is zero, then the carry output 88 will be zero. Therefore, the carry output 88 represents the averaged output of each cell bit over the number of messages received.
The serial to parallel converter 90 gives 8 bit parallel outputs at one time. These are fed into the synch ; detector 91 which gives a high output at 92 when a bits combin~
ation of 0111 1110 is detected. When a reset pulse iis applied at 93, counters 86 and 87 are reset and, at the same time, ~; monostable 94 is triggered, giving an output for a period of at least one word (32 bits) long disabling the multip:Lexer 84 .
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-and setting all the inputs of the shift register array 83 to ~.
zero. This loads zeros into the shift registers, clearing them within 32 bits time.
Figure 17 is a block diagram of a simplified form of line converter, which may be utilized in substitution for ~ .
the more complex embodiment of Figure 13. In this arrangement, :
which is of relatively low cost, the digital processor is greatly reduced in size and complexity. It will be seen that :
the signals received by the ultrasonic receiver-modulator 51a are transmitted via a radio frequency generator-modulator 101 and a subcarrier demodulator 102 to the isolator 57 which, in turn, is connected to the power line (e.g., 110 V. AC).
E'igures 18 and 18A show alternative embod:iments of pass.ive circuitry whereby a line converter or any ~evice using :~ the power line as a communucation medium may be partially super- .
vised by the master controller 13 to detect a condition where .
one or more line converters have been actuated. In both embodi-ments an isolator 106 decouples the power-line voltage (e.g., 110 V. 60 cycle) from the circuitry. In Figure 18, a frequency-dependent impedance network 106 is connected via the isolator ; 1.05 to the power-line system :in series with a normally open contact 107 in the converter to be supervised. In Figure 18A, an impedance network 108 is provided having a transormer type inductance 109, the secondary winding of which is shunted by a normally-closed contact 110 in the device to be supervised.
Upon the closure or contact 107 or the opening of contact 110, a low impedance or a narrow frequency band is presented across the power line and this impedance change can be detected by a sensor in the supervisory circuit ~hereinafter to be described) :`
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of the master controller 13. More than one ce.nter f:requency 16. .

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can be used to indicate various types of equipment operation indicative o~ an emergency situation (e.g., burglary, Eire, etc.) and combinations of frequencies can be used ~or digitally coding the line converter. Since more than one line converter, connected to the same line, may be sirnultaneously actuated without causing interference, it is thus possible for the supervisGry circuit o~ the master controller to indicate that any one or more of such converters have been actuated.
Figure 19 shows an alternate embodiment of circuitry providing for full supervision of line converters with respect to occurrence of actuation and/or malfunction or some disability such as disconnection from the power line, dead battery, power-line breach and the like. The apparatus of the circuitry shown in Figure 19 comprises a tuned circuit 111, which with an RF
amplifier 112 senses RF signal pulses sent by the master con-troller supervisory circuit, later to be described, at a center frequency o~ Fc. These RF pulses are detected and amplified by a pulse detector 113, giving a series of clock pulses. At certain time intervals, the RF pulses are gated ofE for 8.3 milliseconds (m.secs) giving synchronizing pulses which are detected by a synchronizing pulse detector 114. The clock ; pulses are supplied to an 8-bit counter 115 at 116 and serve `~ to increment it, while the synchronizing pulses are applied to the counter 115 at 117 and serve to reset it.
-; Each line converter is assigned a uni~ue time slot within 128 time slots, and this aSSigNment is prograr~ned into the device by a diode network 118. Each time slot is in turn divided into two halves, one half being used to indicate a normal connected device, and the other hal~ being used to in-; 30 dicate an actuated condition. When a time slot assigned to 17.
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7~i~5 the device matches the time slot indicated by the counter 115, as detected by timing detector 119, a monostable 120 is trig-gered on either half of the time slot depending on the condition of the actuator switch 121. Pulse stretcher 122 ensures that the effect of the actuation of swi-tch 121 stays long enough (e.g., 5-10 seconds) to be detected by subsequent scan cycles, (each scan cycle taking about 2 seconds ~or 128 devices). The output of monostable 120 enables the gated RF generator 123, sending an RF pulse with a centex frequency of Fs via the ne-t-work 124 for about 6 milliseconds (m.secs) to the master con-troller 13. Failure of the RF generator 123 to send an RF
pulse response within the time slot assigned indicates that the device is either disconnected or has mal~unctloned.
Figure 20 shows the timing diagram for the RF pulses 125 sent by the supervisory circuit of the master controller 13, the clock pulse output 126, RF generator outputs at a normal condition 127, or at an actuated condition 128 with respect to the time slots. While the number of time slots has been selected as 128, any number larger or smaller than 128 may be selected, depending on the number of conver~ers to be super-vised, with sui~able alteration of circuitry.
Figure 21 shows, in block diagram form, the speci~ic component elements of the master controller 13. As isolator 131 isolates the power line voltage (e.g., 110 V. AC-60 cycle) circuit from the signal circuitry. The RF signal transmitted by a line converter (see Figure 11) is sensed, amplified and demodulated by the RF receiver-demodulator 132 which delivers a subcarrier output that is further demodulated by the subcar-rier demodulator 133. The data output from this demodulator 133 is fed into a digital processor 134 to be processed, 18.

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analyzed and stored. Upon completion of ~he processing, a reset command is sent to the RF transmitter 135 which transmits an acknowledge and reset signal to the transmitting line relay receiver. Local decoding either fully or partially may be performed by the digital processor 134 and results displayed and/or announced by the annunciation and display device 136, such as bell, siren, print out and the like. In addition, commands to remote devices may be sent by means of transmitter 135. In addition, these information/data and the master con-troller identification and status code may be relayed/transmitted .. . .
to a central station, for example, central station 15 i.n Figure1, by means of a communicator 137 through any one of various ; communication media, such as telephone, raclio, coaxial cable, high-voltage power line and the like. The digital processor 134 may be similar to the digital processor 52 shown in Figure 14 but arranged for handling the identification and status codes of the sensors and the line converters. If desired, a more sophisticated digital processor may be employed involving a micro-computer system.
The supervisory circuitry 138, interposed between the diyital processor 134 and the isolator 131, serves to detect malfunctioned or disconnected line converters or other remote devices utilizing the power-line circuitry as a signal communication means. Details of the supervisory circuitry 138 ' are shown in Figure 22 and will now be briefly described. A
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tuned RF amplifier detector 141 detects signals sent by a responding line converter or other remote device and tuned to frequency Fs. A second tuned amplifier detector 142 is tuned slightly of~ Fs and the outputs of the two amplifier cletectors (141, 142) are fed into a comparator 143. Any noise pulses or ' .

19.
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76~95 signals which are broad band in nature will appear on both outputs and will cancel each other. A signal sen~ by a device under a noisy condition will appear in the output of ampliE.ier detector 141 slightly above the output of amplifier detector 142, and the difference in outputs will be detected by the comparator 143. The output 144 of the comparator is sent to the digital processor (see 134 of Figure 21) to be evaluated along with the time slot indicated by counter 145 which appears as an 8-bit address 146. .
Counter 145 is incremented by a 120 cycle clock~ ~
generator 147. Synch detector 148 detects the conditi.on when ;.
the counter indicates time slot zero. RF yenerator 1~9 is ..
gated in such a way that during a synch pulse or when the cloc]c generator 147 is low Eor approximately 2 millisecond"
the RF generator is turned off. However, upon command from the digital processor (134 in Figure 21) presented at the scan .
inhibit input 150, the RF generator remains turnecl on regard- .
less of the conditions of the synch detector 1~8 or clock .
generator 147. The scan inhibit is used when the master con- .
troller requests that the message stored in a device, such as a line converter, be transmitted for decoding at the master controller.
Figure 23 shows, in diayrammatic block ~orm, the essential components o~ the central:station (e.g., 15 of Figure 1). The apparatus comprises a communicator module 152 which receives and transmits message signals from and to a master controller. From the communicator module 152, the digital signal is transmitted to a demodulator 153, which :~ .
extracts the digital message to be processed/ analyzed, de-:~ 30 coded and stored by the digital processor/computer 15~o The ~"

. 20 ' - . ~ ., . .. , . : .

s messages are decoded into the identification code of the sensor, type of emergency, line converter identification code and status and the master controller identification code and status.
These are displayed or printed out on the annunciation device 155. eommands may in turn be sent to the master controller through the modulator 156 and co~.unicator 152. ~ .
While we have shown and described herein-a preferred embodiment and several alternative embodiments of a security system, it will be seen that modifications may be made within the terms of the following claims.

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Claims (10)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A security system for a given security area, said system comprising:
(a) security breach detecting means actuable responsively to occurrence of a breach condition within said area, (b) a sensor for encoding and transmitting self-identification signals responsively to actuation of said breach detecting means, (c) communication means comprising two lines of a secondary power distribution system of which at least one line is a phase line, (d) line converter means connected between said two lines of the secondary power distribution system, said converter means receiving said coded signals, adding its own self-identification code thereto, and transmitting the resulting synthesized line converter signal at radio frequencies along said two lines, and (e) master controller means comprising:
(i) receiver means coupled to said two lines for receiving line converter signals and decoding a plurality of trains of coded line converter messages, (ii) variable memory means coupled to said receiver means for storing a plurality of said coded line converter messages, (iii) receiver memory means coupled to said receiver means for identifying the nature of the transmission mode of each line converter signal received by said receiver means, and (iv) status memory means coupled to said variable memory means and said receiver memory means for synthesizing a status mes-sage from said coded line converter messages, the nature of the transmission mode of each of the line converter signals received and the status of the said security system including said master controller.

2. A security system for a given security area, said system comprising:
(a) security breach detecting means actuable responsively to occurrence of a breach condition within said area, (b) a sensor for encoding and transmitting self-identification signals responsive to actua-tion of said breach detecting means, (c) internal communication means limited to said given security area, comprising two lines of a secondary power distribution system of which at least one line is a phase line, (d) line converter means connected between said two lines of the secondary power distribu-tion system, said converter means receiving said coded signals, adding its own self-identification code thereto, and transmitting the resulting synthesized line converter signal at radio frequencies along said two lines, (e) communication means extending externally from said security area, (f) a plurality of master controller means each comprising line receiver means connected between said two lines of the secondary power distribution system, means for decoding and registering said synthesized line converter signals, and communicator means coupled to said externally extending communication means, for transmission of information beyond said given security area, and (g) central station means outside said given security area comprising:
(i) central station receiving means connected to said externally extending communication means for receiving commun-ication signals from any one of said plurality of master controllers along said externally extending communication means, (ii) central station means for de-coding and registering signals received from a plurality of said master controllers, (iii) central station transmission means for transmitting coded messages and signals back to a plurality of master controllers along said externally extending communication means, for the remote control of functions and for the remote registration of the status of the security system, (iv) central station storage means for storing a plurality of signals received from a plurality of master controllers, (v) central station message checking means for examining all received signals for consistency in the information conveyed by each coded message within the signal, thereby requiring a continuous reception of messages and signals from each master controller that is in communication with said central station until the message-checking procedure reveals that the quality of information received is above a predetermined fixed level, and (vi) central station interpreter means, for interpreting a plurality of conditions of security breach and a plurality of status conditions transmitted by a plurality of said master controllers connected to said central station means.

3. A security system according to claim 2, wherein said central stations means further comprises:
(a) central station audible alarm means coupled to said central station receiving means, for alerting the operators manning said central station means to the arrival of a plurality of messages from a plurality of master controllers, and (b) central station display means for the display of a plurality of coded sensor messages, coded line converter messages, and other coded message.

4. A security system for a given security area, such system comprising:

(a) security breach detecting means actuable responsively to occurrence of a breach condition, (b) a sensor for encoding and transmitting self-identification signals responsively to actuation of said detecting means, (c) communication means comprising two lines of a secondary power distribution system of which at least one line is a phase line, (d) line converter means connected between said two lines of the secondary power distribution system, said converter means receiving coded signals, transmitted by said sensor, adding its own self-identification code thereto, and transmitting the resulting synthesized line converter signal at radio frequencies along said two lines, and (e) master controller means comprising line receiver means connected between said two lines of the secondary power distribution system, and means for decoding and registering said synthesized line converter signals.

5. A security system according to claim 4, wherein said sensor comprises:
(a) sensor triggering means coupled to said security breach detecting means, for triggering and activating the entire circuitry of the sensor means for predetermined periods of time following detection of a security breach by said breach detecting means, (b) memory means for storing digital informa-tion to provide self-identification of said sensor means, (c) message means coupled to said memory means for synthesizing a coded sensor message from the self-identification digital information, (d) message timer-counter means coupled to said message means for repeating said coded sensor messages periodically for said predetermined periods of time, thereby generating a train of said coded sensor messages, and (e) transmission means coupled to said message means and message repeating means for converting said train of coded sensor messages into a modulated signal with a predetermined carrier frequency suitable for transmission by radiation.

6. A security system for a given security area, said system comprising:
(a) security breach detecting means actuable responsively to occurrence of any one of a plurality of breach conditions, (b) a sensor for encoding and transmitting self-identification signals responsive to actuation of said detecting means, (c) a first communication means within said security area comprising two lines of a secondary power distribution system of which at least one line is a phase line, (d) line converter means connected between said two lines of the secondary power distribution system, said converter means receiving said coded signals, adding its own self-identification code thereto, and transmitting the resulting synthesized line converter signal at radio frequencies along said two lines, (e) a second communication means extend-ing externally from said security area, (f) master controller means comprising line receiver means connected between said two lines of the secondary power distribution system, means for decoding and registering said synthesized line converter signals, and communicator means coupled to said external extending communication means, for transmission of information beyond said security area, and (g) central station means outside said security area comprising communicator means coupled to said externally extending communi-cation means, and means for decoding and registering signals received from said master controller means.

7. A security system according to claim 4, wherein supervisory circuitry partly in said line converter and partly in said master controller automatically detects any breach in communication via said secondary power distribution system and registers same at the master controller.

8. A security system according to claim 4, in which said line converter means comprises:
(a) converter receiver means for receiving and demodulating sensor signals of predetermined carrier frequency from said sensor, (b) converter memory and digital processor means coupled to said converter receiver means, for discriminating, extracting and storing a train of coded sensor messages, for storing a converter self-identification code for said line converter, and for synthesizing a train of coded line converter messages from said train of coded sensor messages and said con-verter self-identification code, and (c) converter transmission means coupled to said converter memory and digital processor means for converting said train of coded line converter messages into a modulated line con-verter signal with a predetermined carrier frequency suitable for transmission on said two lines of the secondary power distribution system.

9. A security system according to claim 8, in which said line converter means additionally comprises means to prevent a plurality of line converters from communicating simultaneously with the same master controller, thereby eliminating possible interference in communication.

10. A security system according to claim 4, wherein said master controller further comprises:
(a) supervisory circuitry means for auto-matically detecting and registering any breach in communication between said line converter means and said master controller means via said two lines of the secondary power distribution system.