US3710372A - Alarm system for monitoring a plurality of serially connected objects utilizing signal translation techniques - Google Patents

Alarm system for monitoring a plurality of serially connected objects utilizing signal translation techniques Download PDF

Info

Publication number
US3710372A
US3710372A US00096332A US3710372DA US3710372A US 3710372 A US3710372 A US 3710372A US 00096332 A US00096332 A US 00096332A US 3710372D A US3710372D A US 3710372DA US 3710372 A US3710372 A US 3710372A
Authority
US
United States
Prior art keywords
signal
input
objects
loop
guarded
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00096332A
Other languages
English (en)
Inventor
T Andersson
S Warring
L Isheden
B Johansson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Application granted granted Critical
Publication of US3710372A publication Critical patent/US3710372A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/04—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using a single signalling line, e.g. in a closed loop
    • G08B25/045—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using a single signalling line, e.g. in a closed loop with sensing devices and central station in a closed loop, e.g. McCullough loop
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
    • G08B29/02—Monitoring continuously signalling or alarm systems
    • G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults
    • G08B29/08—Signalling of tampering with the line circuit

Definitions

  • An arrangement for causing an alarm in a guarding device for example a burglary alarm device, includes a central guarding unit which sends out control signals through a loop to a number of objects to be guarded.
  • the objects are connected in series with the guarding unit and upon unwarranted manipulation with the loop, for example upon attempts to by-pass an object, an alarm is obtained.
  • Each object to be guarded comprises a signal translating means which translates the signal obtained through the loop in a manner characteristic of the respective object.
  • the central guarding unit compares the control signal sent out from the guarding unit, with the signal sent back from the objects to be guarded. At least one of said two signals is translated before the comparison in order to obtain the same translation which has been obtained in the object to be guarded. During a comparison when an inequality between the two signals is sensed the alarm device is operated.
  • Drawing Figure mm 9 was KTLZI 85 E NTO RS nssvuunm Luuouflunnsson Lgas Rune Isuzaew Bo Emu. Jomwssam srle EmKWmmme BM WM, 16%
  • This invention refers to an arrangement for causing an alarm in the guarding unit of a guarding device, for example a burglary alarm device, in which a central guarding unit sends out a control signal through a loop to a number of objects to be guarded which are connected in series with the guarding unit, upon unwarranted manipulation with the loop, for example upon attempts to by-pass one or more objects to be guarded.
  • a central guarding unit sends out a control signal through a loop to a number of objects to be guarded which are connected in series with the guarding unit, upon unwarranted manipulation with the loop, for example upon attempts to by-pass one or more objects to be guarded.
  • each object to be guarded should be provided with an alternator, the output signal of which is superimposed on a direct current supplied from the central guarding unit through the loop.
  • Supervision of both the direct and the alternating current is in this case carried out in the guarding unit.
  • An object of the invention is to provide an arrangement in which a number of objects to be-guarded can be supervised by means of one single loop and in which the alarm system cannot be defected by by-passing one or more objects to be guarded and where an object to be guarded which is exposed tounwarranted manipulation, for example by-passing, is immediately identified in the guarding unit.
  • the guarding device consistsof a central guarding unit C, to which a number of objects to be guarded B1, B2 Bn are connected in series through a current loopa.
  • Each object to be guarded includes in the known manner an alarm detector and an alarm contact which are diagrammatically shown as a relay function R1, R2 Rn.
  • the alarm detectors as well as the alarm contacts are assumed to be inaccessible to undue actuation.
  • a control signal is sent out from the guarding unit C through the loop.
  • this control signal is translated in each of the objects to be guarded, in a predetermined manner characteristicof the respective object to be guarded.
  • the signal obtained is then compared, taking in consideration the translations carried out by the objects to be guarded, with the control signal sent out from the guarding unit C.
  • the signals compared- will be equal. if, however, one of the objects to be guarded is by-passed, the expected translation of the control signal in this object will be lacking upon the comparison and alarm is initiated in the guarding unit.
  • the control signal sent out through the loop a to the objects to be guarded B1, B2 Bn is supposed to be a pulse train which is generated by for example a random sequence generator G.
  • Each object to be guarded includes, besides said alarm detector and alarm contact,
  • the signal translating means consists of an exclusive-orcircuit E11, E12 EIn-to which are supplied on one hand the pulse train incoming to the respective object to be guarded through the loop a and on the other hand a pulse train individual for each object to be guarded.
  • This pulse train is generated by a generator G11, G12 Gln according to a previously known pattern.
  • the translated signal is supplied through the loop a from the object Bn to be guarded to the central guard ing Unit C.
  • this signal is to be compared with the control signal sent out from the guarding unit considering the known translations carried out in the objects to be guarded. This can be solved in many different ways.
  • a comparison circuit K is provided, tov
  • a pulse train is supplied from the generator G which train is subjected to the same known translations as the pulse trains transmitted through the loop a
  • the translations occur in a signal code translating means SK which according to the example comprises a number of exclusive-or-circuits E21, E22
  • E2n and pulse generators, G21, G22 G2n corresponding to the number of objects to be guarded.
  • These pulse generators are identical with the pulse generators G11, G12 Gln in the objects to be guarded.
  • the pulse train obtained from the signal code translating means SK is identical with the pulse train incoming through the loop provided that no ob ject to be guarded has been by-passed.
  • an alarm signal is generated which may actuate an alarm device L in the guarding unit.
  • the guarding unit C is provided with an identifying means IM.
  • This is assumed, according to the example, to consist of parallel comparison branches the number of which corresponds to the number of objects to be guarded.
  • Each of these comparison branches contains an exclusive-or-circuit E31, E32 E3n to one of the inputs of which the pulse train incoming through the loop a is supplied.
  • a pulse generator G31, G32 6301 is connected to the second input of the respective exclusive-or-circuit.
  • These pulse generators are identical with the pulse generator G11, G12.. Gln of the respective object to be guarded.
  • the pulse train obtained on the respective exclusive-orcircuit E31, E32 E3n is conducted to one of the inputs of an individual comparison circuit K1, K2 Kn.
  • an individual comparison circuit K1, K2 Kn To the other input of the respective comparison circuit the pulse train incoming from the signal code translating means SK is supplied.
  • Alarm in the guarding unit C is obtained not only when an object to be guarded has been by-passed but also when an alarm is detected in one of the objects to be guarded.
  • the corresponding alarm detector R1,R2 Rn is activated, its alarm contact interrupting the connection from the respective pulse generator G11,G12 Gln. No translation of the signal through the loop a occurs in this object to be guarded-In the same manner as described above an alarm will be obtained in this case in the guarding unit C from the alarm device L as well as from that one of the alarm devices L1,L2 Ln which corresponds to the object to be guarded giving the alarm.
  • the signal code translating means SK can very well be connected in series with the loop a between the object to be guarded Bn and the comparison circuit K instead of between the pulse generator G and the comparison circuits K, K1, K2. Kn as is shown in the FIGURE.
  • the pulse generator G is connected directly to the upper inputs of the comparison circuits K, K1,K2. Kn.
  • An alarm system comprising a central guarding unit, a plurality of objects to be guarded and a loop connecting said objects to be guarded in series with said central guarding unit, said central guarding unit including means for transmitting a control signal through said loop to said different objects to be guarded, each of said objects to be guarded comprising a signal translating means including a signal generator, a function generator provided with a first input for receiving said control signal transmitted through said loop and a second input for receiving the signal generated by said signal generator, said function generator generating on an output a signal which is a definite function of the input signals, each of said objects furthermore including an alarm detector having means for disconnecting said signal generator from the respective input of said function generator upon manipulation of the object to be protected to cause an interruption'of the signal translation in the respective signal translating means, and said central guarding unit further comprising a comparison circuit for comparing the transmitted control signal with the control signal returning through the loop from the objects to be guarded after having subjected at least one of said signals to a further translation, and
  • the signal code translating means translates the same control signal which is supplied to said loop and has an output connected to one input of said comparison circuit in order to supply translated signals to said input. selected 3.
  • the signal code translating means translates the control signal received through the loop from the objects to be guarded and has an output connected to one input of said comparison circuit in order to'supply translated signals to said input.
  • the central guarding unit further comprises identifying means for identifying which of said objects has caused alarm, said identifying means comprising parallel branches whose number equals the number of objects to be guarded, each of said branches comprising a signal translating means each identical with a corresponding signal translating means of one of said objects and a comparison circuit in series, said signal translating means each having an input for receiving the signal incoming from said loop and an output connected to a first input of the respective comparison circuit in order to supply translated signals to said input, each of said comparison circuits having a second input for receiving said control signal so upon equality between the two compared signals in anyone of the comparison circuits an indication is given as to which of said objects has caused alarm.
  • An alarm system comprising: signal generating means having an output for generating coded combinations of signals; a plurality of objects to be guarded, each of said objects'comprising a signal generator for generating coded combinations of signals; a function generator having first and second inputs and an output for transmitting from said output coded combinations of signals related to coded combinations of signals received at said inputs, said first input being the signal input of the object and said output being the signal output of said object; an alarm detector means for connecting said signal generator to the second input of said function generator as long as the object is undisturbed; means for serially connecting the signal input of one object to the signal output of another object to form an open loop of serially connected objects with the signal input of the object at one end of said loop being the loop signal input and the signal output of the object at the other end of said loop being the loop signal output; a comparator means having first and second inputs for comparing coded combinations of signals received at said inputs; first connecting means for connecting the output of said signal generating means to said loop signal input; second connecting

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Burglar Alarm Systems (AREA)
  • Alarm Systems (AREA)
US00096332A 1970-01-08 1970-12-09 Alarm system for monitoring a plurality of serially connected objects utilizing signal translation techniques Expired - Lifetime US3710372A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE00162/70A SE329358B (enrdf_load_stackoverflow) 1970-01-08 1970-01-08

Publications (1)

Publication Number Publication Date
US3710372A true US3710372A (en) 1973-01-09

Family

ID=20256131

Family Applications (1)

Application Number Title Priority Date Filing Date
US00096332A Expired - Lifetime US3710372A (en) 1970-01-08 1970-12-09 Alarm system for monitoring a plurality of serially connected objects utilizing signal translation techniques

Country Status (6)

Country Link
US (1) US3710372A (enrdf_load_stackoverflow)
DE (1) DE2064858C3 (enrdf_load_stackoverflow)
DK (1) DK124153B (enrdf_load_stackoverflow)
GB (1) GB1295189A (enrdf_load_stackoverflow)
NO (1) NO124613B (enrdf_load_stackoverflow)
SE (1) SE329358B (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792469A (en) * 1972-07-17 1974-02-12 Johnson Service Co Multiplexed alarm transmission system having alarm storage circuits
US4229734A (en) * 1978-10-26 1980-10-21 Honeywell Inc. Line supervision
US4240078A (en) * 1978-06-07 1980-12-16 Minnesota Mining And Manufacturing Company Frequency selective annunciator system
US4262284A (en) * 1978-06-26 1981-04-14 Stieff Lorin R Self-monitoring seal
US4268823A (en) * 1979-11-02 1981-05-19 Ici Americas Inc. Protective electrical system for providing indications of removal of objects from plural monitored locations by use of parallel-connected object-sensors
US4555930A (en) * 1984-02-14 1985-12-03 Control Instruments Corp. Digital gas sensing system
US4577184A (en) * 1983-05-23 1986-03-18 Tetra-Tech, Inc. Security system with randomly modulated probe signal
US4716401A (en) * 1985-09-19 1987-12-29 Deere & Company Tamper-resistant supervisory system
USD330339S (en) 1990-08-08 1992-10-20 Joseph Roselle Motion detecting alarm

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2324172A1 (fr) * 1975-09-15 1977-04-08 Gautier Gerard Dispositif de protection antifrauduleuse pour ligne telephonique exploitee en transmission d'alarme
SE7803437L (sv) * 1978-03-28 1979-09-29 Saab Scania Ab Forfarande for att vid en anleggning vars enheter er sammanbundna medelst en kommunikationsledning for informationsberande signaler, kontinuerligt overvaka tillstandet for de till kommunikationsledningen anslutna ...
JPS61177841A (ja) * 1985-02-04 1986-08-09 Mitsubishi Electric Corp 直列伝送装置
ES2040786T3 (es) * 1987-08-14 1993-11-01 Siemens Aktiengesellschaft Procedimiento de transmision de datos.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2423649A (en) * 1944-12-08 1947-07-08 Horvitch Gerard Michael Electric burglar alarm
US3253270A (en) * 1963-08-02 1966-05-24 Downer Frank Theft alarm for shoplift prevention

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2423649A (en) * 1944-12-08 1947-07-08 Horvitch Gerard Michael Electric burglar alarm
US3253270A (en) * 1963-08-02 1966-05-24 Downer Frank Theft alarm for shoplift prevention

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3792469A (en) * 1972-07-17 1974-02-12 Johnson Service Co Multiplexed alarm transmission system having alarm storage circuits
US4240078A (en) * 1978-06-07 1980-12-16 Minnesota Mining And Manufacturing Company Frequency selective annunciator system
US4262284A (en) * 1978-06-26 1981-04-14 Stieff Lorin R Self-monitoring seal
US4229734A (en) * 1978-10-26 1980-10-21 Honeywell Inc. Line supervision
US4268823A (en) * 1979-11-02 1981-05-19 Ici Americas Inc. Protective electrical system for providing indications of removal of objects from plural monitored locations by use of parallel-connected object-sensors
US4577184A (en) * 1983-05-23 1986-03-18 Tetra-Tech, Inc. Security system with randomly modulated probe signal
US4555930A (en) * 1984-02-14 1985-12-03 Control Instruments Corp. Digital gas sensing system
US4716401A (en) * 1985-09-19 1987-12-29 Deere & Company Tamper-resistant supervisory system
USD330339S (en) 1990-08-08 1992-10-20 Joseph Roselle Motion detecting alarm

Also Published As

Publication number Publication date
DE2064858C3 (de) 1974-05-30
DK124153B (da) 1972-09-18
NO124613B (enrdf_load_stackoverflow) 1972-05-08
DE2064858A1 (de) 1971-07-15
DE2064858B2 (de) 1973-10-31
GB1295189A (enrdf_load_stackoverflow) 1972-11-01
SE329358B (enrdf_load_stackoverflow) 1970-10-05

Similar Documents

Publication Publication Date Title
US3710372A (en) Alarm system for monitoring a plurality of serially connected objects utilizing signal translation techniques
US3833895A (en) Intrusion alarm with indication of prior activation
US3711846A (en) Segment locating intrusion alarm system
US4749853A (en) Light barrier having multiplexer for actuating transceiver pairs and multiple channel operation
US3735353A (en) Alarm transmission line security system utilizing pseudo random encoding
GB2116808A (en) Randomized tag to monitoring station communication system
US3803594A (en) Programmed time division multiplexed coded tone transmission system
GB926688A (en) Signalling system
RU2310236C1 (ru) Устройство для имитозащиты контролируемых объектов
US3035248A (en) Remote control systems
US2298840A (en) Alarm system
US3970940A (en) Overall equipment condition checking
GB1255221A (en) Improvements in or relating to an alarm device and a supervising installation including said device
US3806921A (en) Detector device
US3161732A (en) Testing and control system for supervisory circuits in electronic telephone exchanges
US3380023A (en) Electronic alarm system
US3449738A (en) Electronic security system
US3792469A (en) Multiplexed alarm transmission system having alarm storage circuits
RU2387017C2 (ru) Система сопряжения устройств для имитозащиты контролируемых объектов
US3686439A (en) Telephone-line installation for keeping a remote watch on premises
US1816621A (en) Testing system
US4070669A (en) Anti-fraud alarm transmission line security system
US2275981A (en) Alarm system
JPS58169079A (ja) 放射線異常検出装置
US1625823A (en) Radio receiver and trouble alarm