1.415185
`
`XR
`
`444944111
`
`United States Patent [19]
`Rocci et al.
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,494,111
`Jan. 15, 1985
`
`[54] FREQUENCY AGILE SECURITY
`APPARATUS
`
`[75] Inventors: Joseph D. Rocci, Lansdale; Stephen
`E_ Crook, Horsham; Marc Kauffman’
`Elkins Park, an of Pa.
`[73] Assignee: General Instrument Corporation, .
`New York’ NY"
`[21] Appl. No.: 328,301
`.
`Dec‘ 7’ 1981
`[22] Flled:
`[51] Int. Cl.3 ........................ .. G08B l/08; H04N l/OO
`[52] US. Cl. .................................. .. 340/533; 340/505;
`340/531; 340/8508; IMO/825.54; 455/3;
`358/36; 375/ 36
`_
`[58] Field of Search ............. .. 340/533, 531, 532, 518,
`340505407’ 536' 825-21’ 82506-82513’
`825-29’ 825-52’ 825'54’ 870'09’ 87016’ 870-18’
`87_03‘2g;
`9R1; 2P ; 81678347653 I156’
`4A5’
`693
`C’ 5 / ’
`’
`’
`’
`/14’ 1’5 17 63 ’26
`’
`’
`’
`’
`
`[56]
`
`,
`
`,
`
`v References Cited
`Us. PATENT DOCUMENTS
`340/825 54
`3 742 452 6/1973 A d t h t 1
`3,761,914 9/1973 Hardy et al. ...................... .. 340/533
`3,803,491 4/1974 Osborn ................. .. 340/825.54
`4,066,966 l/ 1978 Takeuchi et al. .
`..... .. 340/310 R
`4,075,628 2/1978 Masuda et a1. .............. .. 358/86
`
`u re sc e a. .......... ..
`
`.
`
`4,114,150 9/1978 Yamazaki et al. ................ .. 340/531
`4,245,245 l/ 1981 Matsumoto et al. .............. .. 358/122
`4,408,345 10/1983 Yashiro et al. ............... .. 340/825.08
`_
`_
`Primary Examiner—Donn1e L. Crosland
`Attorney, Agent, or Firm—Allan Jacobson
`[57]
`ABSTRACT
`A cable TV security system utilizes three radio fre
`quency signals as three data communication channels:
`one downstream channel and two upstream channels. A
`headend alarm processor transmits system commands
`on the downstream channel. A plurality of subscriber
`alarm units, connected to the cable TV system, transmit
`messages on the upstream channels to the headend
`alarm processor. The respective center frequency of
`both upstream channels is selectable by command on
`the downstream channel transmitted from the headend.
`In the event that one subscriber’s alarm unit malfunc
`tions whereby a continuous stream of upstream trans
`mission jams one of the upstream channels, the headend
`alarm processor changes the respective transmitter fre
`quency of the remaining subscriber alarm units to a
`clear channel frequency. Alternatively, the frequency
`or frequencies of the malfunctioning unit may be
`waged‘ I“ elctlher case’ System secumy coverage 15
`rap‘ Y restore -
`
`-
`
`-
`
`-
`
`6 Claims, 15 Drawing Figures
`
`POLLING
`MN POLLING
`mmsmrrza CHANNEL
`
`26
`7
`
`32
`W04?“
`CABLE TV
`
`36
`
`2e
`
`SYSTEM "
`
`34?
`
`__
`
`IG’N
`
`.
`
`12:112..
`ISL
`RALARMR
`ECEIVE
`
`l—>
`
`551st
`3°
`
`CHANNEL
`
`CONTROLLER
`
`I20
`
`J2
`
`38 '_—1 r”
`518.51%;
`447
`l
`l
`l
`MICROPROCESSOR —- 5535:2522;
`
`46
`
`42
`
`HEADEND ALARM PROCESSOR
`
`48
`
`CENTRAL SYSTEM 'x/
`COMPUTER
`22
`
`47¢
`
`CONTROL
`CONSOLE
`
`SUBSCRIBER ALARM PROCESSOR
`
`1a
`
`ARRIS883IPRI0001000
`
`

`
`U.S. Patent
`
`Jan
`
`.15,
`
`1985
`
`Shcetl ofll
`
`4
`
`,494
`
`,111
`
`>ozm:omE
`
`mmN_mm:»z>m
`
`
`
`mmt_zmz<Emm>_uomm
`
`
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`Emiowmammmmaommsm
`
`:m»m>mmm
`
`om
`
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`
`0Z_._;_On_oz_._._oa
`
`
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`zm:h.Emm>_moum
`
`
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`.m_2z<_..umm>_mumm
`
`2m<._<
`
`mm._._oEzoo
`
`.6528
`
`mjcmzoo
`
`
`
`_2u..m>mimkzmo
`
`mafia$.00
`
`
`
`
`
`mommuoomm_2m<4<ozmofi:
`
`
`
`>._.m._m<u
`
`
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`><s>.O3._.._mzz<:ommC__2mz<E
`
`mm
`
`
`
`oz_._._omoZ_._:_On_
`
`ARRIS883IPRI0001001
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet 2 of 11
`
`4,494,1 1 1
`
`|B5|B4IB3| LB2|BI|B0I
`IBTIBS]
`L, , C
`v
`4
`2 CONTROL
`6 COMMAND 0R
`BITS
`ADDRESS BITS
`
`-
`F76 2
`
`-
`B5 — Bo
`B7 B6
`W0 0 o I_owER 6 BITS OF I8 BIT SUBSCRIBER ADDRESS
`WI 0 I MIDDLE 6 BITS OF IS BIT SUBSCRIBER ADDRESS
`w2 I
`o UPPER 6 BITS OF 18 BIT SUBSCRIBER ADDRESS
`we, I
`I COMMAND CODE
`
`T
`
`T-9
`
`PM
`
`I
`
`I
`
`I
`
`I
`
`I
`
`I
`I
`I
`I
`17.75 23.75
`POLLING RETURN
`AND
`ALARM FREQUENCIES
`
`I
`I
`50
`
`.L
`
`I
`
`III I
`
`:
`I
`I
`108,
`88
`POLLING
`CHANNEL
`FREQUENCY
`
`‘if
`MHZ
`
`ARRIS883IPRI0001002
`
`

`
`U.S. Patent Jan. 15,1985
`
`Sheet 3 of 11
`
`4,494,111
`
`$6; 3.3
`
`
`
`.Lwia ._._<_1.wm|||ll_|||||||_
`
`30.6
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`
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`<20 8585 IL
`
`wish E3 “65 >55
`
`5
`
`ARRIS883IPRI0001003
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet4ofl1
`
`4,494,111
`
`GLOBAL COMMANDS. m [LT/6-5
`W3
`
`OPERATION
`NAME
`CODE
`37? INTER-RECORD GAP (IRG) SYNCHRONIZING SIGNAL
`367 ALL QUIET
`STOP UPSTREAM TRANSMISSION
`ON ALARM CHANNEL
`REQUEST UPSTREAM TRANS
`MISSION ON ALARM CHANNEL
`SET POLLING RETURN AND
`ALARM CHANNEL FREQUENCIES
`AS QEFINED IN SUBSCRIBER PROM
`LOCAL ALARM ONLY, STOP
`UPSTREAM TRANSMISSION
`ALL OPERATE ON BATTERY
`ALL OPERATE ON PRIMARY AC
`RESET TO INITIAL CONDITION
`
`353 ALL SPEAK AGAIN
`
`354 RESTORE ORIGINAL
`FREQUENCY
`
`'
`374 ALL STAND ALONE
`
`356 BATTERY TEST ON
`357 BATTERY TEST OFF
`376 RESET
`
`A‘jgg?i?gal
`
`BI>V<IXI2I>§IXIUI>§IXIWI>§IXI
`
`W3
`
`W2
`
`W1
`
`W0
`
`NAME
`CODE
`360 POLLING
`
`352 ALARM VERIFIED
`
`OPERATION
`REQUEST ADDRESSED SUBSCRIBER
`TO ACKNOWLEDGE
`INFORM ADDRESSED SUBSCRIBER
`THAT 'HEADEND HAS RECEIVED
`ALARM MESSAGE
`REQUEST ADDRESSED SUBSCRIBER
`TO SEND ALARM MESSAGE ON
`POLLING CHANNEL
`TURN OFF INTRUSION ALARM
`375 DISARM
`355 LEARN PRIMARY CODE PERMIT SUBSCRIBER TO ENTER
`A NEW PRIMARY CODE
`
`373 DIRECT VERIFY
`
`ARRIS883IPRI0001004
`
`

`
`US. Patent Jan. 15,1985
`
`SheetSofll ‘4,494,111
`
`F/G-7
`QEEEEEZMII 3I >V<I XIIILZBIXIHI 1 IfIXIQI?xIIx I {l xl
`w3
`_w2
`W1
`W0
`wx
`
`OPERATION
`NAME
`CODE
`364 TUNE POLLlNG RETURN TUNE POLLING RETURN CHANNEL
`CHANNEL
`FREQUENCY OF ADDRESSED UNIT
`TO FOLLOWING DATA WORD
`365 TUNE ALARM CHANNEL TUNE ALARM CHANNEL FREQUENCY
`OF ADDRESSED UNIT TO FOLLOW
`ING DATA WORD
`
`GLOBAL DATA: mil - I xIx 1
`W3
`w2 OFIWI or we or wx
`
`F/G-cS’
`
`NAME
`CODE
`362 GLOBAL TUNE ALARM
`CHANNEL
`
`366 ADDRESS SEARCH‘ 0
`
`363 ADDRESS SEARCH I
`
`OPERATION
`TUNE ALARM CHANNEL FRE
`QUENCY OF ALL UNITS TO
`FOLLOWING DATA WORD
`SEND ALARM CODE IF ADDRESS
`MATCHES FOLLOWING ADDRESS
`WORD AND DID NOT MATCH
`PREVIOUS ADDRESS WORD
`SEND ALARM CODE IF ADDRESS
`MATCHES FOLLOWING ADDRESS
`WORD AND DID MATCH PREVIOUS
`ADDRESS WORD
`
`ARRIS883IPRI0001005
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet 6 Of 11
`
`4,494,111
`
`F/G-9
`
`GLOBAL DATA=\L3 l x 1 x1
`wa
`
`wzzrvwI Or
`wO
`
`wvx
`
`OPERATION
`NAME
`cODE
`361 GROUP TUNE POLLING TUNE POLLING RETURN CHANNEL
`RETURN CHANNEL
`TO FOLLOWING DATA wORD IF
`ADDREss MATcI-IEs FOLLOWING
`ADDREss wORD
`
`ALARM CODESEE
`
`O INTRUSION
`I
`FIRE
`2
`UsER DEFINED
`3
`I
`I-
`4
`II
`II
`
`5
`
`6
`
`II
`
`II
`
`II
`
`II
`
`7
`ll
`II
`20 MEDICAL BUTTON
`4O FIRE BUTTON
`IOO FOLIOE BUTTON
`2OO BATTERY FAILURE
`272 TANIPER
`274 CANCEL (SYSTEM DISARMED)
`
`F/G/O
`
`ARRIS883IPRI0001006
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet 7 of 11
`
`4,494,1 l l
`
`I F/G-H
`
`NORMAL POLLING AND DIRECT VERIFY LOGIC
`
`ENTER
`
`POLLING RETURN AND ALARM FREQUENCIES CLEAR?
`
`I02
`FIND CLEAR
`CHANNELS
`AS PER FIG-I5‘
`
`NO
`
`YES
`
`I04
`
`POLL SUBSCRIBER UNITS
`
`POLLING RESPONSE ?
`
`YES
`
`NO
`
`I06
`
`I087
`
`SET CUT .
`CABLE ALARM
`
`T
`
`I167
`SEARCH VERIFY
`AS PER FIG-I3
`
`110’?
`
`y
`
`No ALARM RECEIVED?
`
`YES
`V
`112'}
`ALARM GARBLED ? YES
`
`NO
`
`‘
`114-7
`NO
`DIRECT VERIFY ?
`
`YES
`
`FORWARD ALARM
`CODE TO CENTRAL
`COMPUTER
`
`ARRIS883IPRI0001007
`
`

`
`US. Patent Jan. 15, 1985
`
`Sheet 8 ofll
`
`4,494,111
`
`F/G/Z
`
`NORMAL POLLING AND DIRECT VERIFY SEQUENCE
`
`POLLING RETURN
`
`POLLING CHANNEL
`ALARM CHANNEL
`5 IRG'S
`T20
`POLLING
`T21
`@1111
`T22
`@1111
`3 IRG'S
`T23
`l 2 | x x m
`T24
`[
`1
`I x x
`m
`T25
`126 @3111 m
`T27 ALARM CODE
`m
`T28
`CHECKSUM m
`T29
`[511E
`T30
`T31
`T32
`T33
`T34
`T35
`T36
`T37
`T38
`T39
`T40
`T41
`T42
`
`5 IRG'S
`ALL QUIET
`5 IRG'S
`DIRECT VERIFY
`L; x I x
`. (I x I x
`@1111
`
`4
`
`5 IRG'S
`I I x X]
`IIIXE
`
`ALARM CODE
`CHECKSUM
`
`.
`
`T43
`T44
`T45
`T46
`W
`T48
`T49
`
`> s IRG'S
`ALARM VERIFIED
`@1111
`mm
`@1113
`s IRe's
`ALL SPEAK AGAIN
`
`ARRIS883IPRI0001008
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet9 Ofll
`
`4,494,111
`
`SEARCH VERIFY LOGIC'
`ENTER
`
`122 /
`SET1 IN HIGHEST ORDER ADDRESS BIT
`
`I247
`TRANSMIT SEARCH VERIFY 0
`
`I
`
`I32
`7
`I
`SHIFT I TO NEXT
`LOWER ADDRESS BIT
`INC
`
`'26?
`REPLY REcEIvEo?
`
`1307
`I287
`NO sET BIT IN
`SEARCH REG- T ésEAi'g?ED?
`ISTER TO 0
`'
`
`,YEs
`sET BIT IN
`SEARCH REGISTER
`TO I
`
`[I34
`
`YES
`
`I36
`f
`I
`I8 BITs SEARCHED ? YES
`
`I42
`7 I
`EXIT
`
`~
`
`No
`f'z’e
`I
`SHIFT I TO NEXT
`I_owER ADDRESS BIT
`
`14o
`f
`TRANSMIT SEARCH
`VERIFY I
`
`F7643
`
`ARRIS883IPRI0001009
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet 10 Ofll 4,494,111
`
`F/G-/4
`
`SEARCH VERIFY SEQUENCE
`
`ALARM CHANNEL
`T59 GARBLED ALARM
`T60
`T61-
`we
`T63
`T630
`T64
`T65
`T66
`T67
`
`T68
`T659
`T70
`w
`T72
`T73
`T74
`T75
`
`T76
`T77
`T78
`T79
`T80
`T81
`
`POLLING CHANNEL
`
`POLLING RETURN
`
`s IRG'S
`ADDRESS SEARCH 0
`m
`5 IRC'S
`ADDRESS SEARCH 0
`Ell-12G
`5 IRG'S
`ADDRESS SEARCH 0
`ELIE]
`ETC., UNTIL REPLY
`RECEIVED
`5 IRC'S
`ADDRESS SEARCH 1
`m
`s IRG'S
`ALARM CCDE
`I
`ADDRESS SEARCH 1
`m
`ETC., UNTIL
`NO REPLY RECEIVED
`s IRG'S
`ADDRESS SEARCH 0
`
`ALARM CCDE
`
`5 IRG'S
`ADDRESS SEARCH 0
`
`ETC. FOR REMAINING
`ADDRESS BITS
`
`ARRIS883IPRI0001010
`
`

`
`US. Patent Jan. 15,1985
`
`Sheet 11 of 11 4,494,111
`
`FIND CLEAR CHANNEL LOGIC
`ENTER
`
`15 O’,
`
`F7645
`
`No POLLING RETURN CHANNEL CLEAR .7
`YES
`r152
`GLOBAL TUNE
`-
`NO
`ALARM CHANNEL CLEAR? “- ALARM CHANNEL
`YES
`TO CLEAR FREQUENCY
`
`'54’?
`
`L__I
`
`SET 1 IN HIGHEST ORDER
`ADDRESS BIT
`
`r158
`GROUP TUNE POLLING RETURN
`CHANNEL TO NEW FREQUENCY
`
`{I60
`NEW POLLING RETURN CHANNEL
`CLEAR?
`
`/178
`
`EXIT
`
`I62
`’I
`SET BIT IN
`SEARCH REGISTER
`To 1
`
`No
`
`I64
`
`IYES
`SEI' BIT IN SEARCH REGISTER TO 0
`
`‘661
`RESTORE ALL uNITS
`‘687 {"_"'——- TO ORIGINAL
`FREQUENCY
`I8 BITS SEARCHED? YES
`I707
`NO
`SEARCH ADDRESS =0?
`
`SHIFT I TO NExT
`LOWER ADDRESS BIT
`WEI
`
`,No
`I747
`RESTDRE ORIGINAL
`FREQUENCY
`
`I76’)
`
`TUNE UNIT WITH
`SEARCH ADDRESS To
`ANOTHER FREQUENCY
`
`YES
`
`r/fa
`
`EXIT
`
`ARRIS883IPRI0001011
`
`

`
`1
`
`.
`
`4,494,1 l l
`
`2
`However, a portion of the subscribers on the effected
`feeder line, i.e. downstream of the activated bridger
`switch are without security coverage. Moreover, the
`speci?c location of the jamming subscriber unit must be‘
`5 determined by manually checking the cable system in
`the ?eld.
`
`FREQUENCY AGILE SECURITY APPARATUS
`
`FIELD OF THE INVENTION
`This invention relates to security apparatus utilizing
`two way cable TV systems for transmitting alarm mes
`sages to a central location.
`
`SUMMARY OF THE INVENTION
`The present invention is embodied in a security appa
`ratus responsive to commands from the cable system
`headend for changing the respective frequency of the
`upstream channels, i.e. polling return channel and the
`alarm channel.
`Thus, when one subscriber unit malfunctions, causes
`a jamming signal, the transmitter frequency of each
`respective remaining subscriber unit, responsiveto hea
`dend commands, changes to a clear channel frequency. ,
`Alternatively, the transmitter frequency of the sub
`scriber unit causing the jamming signal changes to an
`other frequency responsive to headend commands,
`thereby leaving the remaining subscriber units on a
`clear frequency.
`Therefore, the security system is rapidly returned to
`operational condition so that interruption in security
`coverage is reduced. Furthermore, the subscriber appa
`ratus that caused the jamming signal is known at the
`headend so that the malfunctioning unit may be located
`without further ?eld testing.
`
`25
`
`BACKGROUND OF THE INVENTION
`10
`A security system utilizing a cable TV communica
`tions system is disclosed in a pending patent application
`entitled “Security System”, by Tom O’Brien, Ser. No.
`328,304 ?led Dec. 7, 1981, which application is assigned
`to the assignee of the present invention. The latter pa
`tent application describes an alarm system utilizing
`three radio frequency signals as data communication
`channels between a headend alarm processor and a
`plurality of subscriber alarm processors. One channel is
`a polling channel on which the headend alarm proces
`sor transmits command messages to all subscriber units.
`Another channel is a polling response channel on which
`an addressed subscriber unit responds to a headend
`command message. The third channel is an alarm chan
`nel on which subscriber units transmit alarm messages
`to the headend essentially when a respective alarm
`condition is ?rst detected.
`Thus, a security system of the type described above
`has one transmitter tuned to the downstream polling
`channel frequency, but a plurality of transmitters re
`spectively tuned to either the upstream polling return
`frequency or alarm channel frequency. If one of the
`plurality of subscriber alarm units should fail in a mode
`wherein a continuous transmission is coupled to the
`cable system, then one or both of the polling return
`channel or alarm channel will be jammed, thereby dis
`abling the entire security system.
`In a security system, continuity of security coverage
`is of great importance. When a system failure does oc
`cur, the system must be restored to proper operation
`quickly so that theres no signi?cant interruption in secu
`rity coverage.
`On prior art solution to the above described jamming
`problem is to use a radio frequency (RF) signal sensor
`coupled to a switching circuit on the output of each
`45
`subscriber transmitter. If the RF signal output from any
`subscriber unit is continuous, i.e. if rf transmission ex
`ceeds a predetermined time duration such as 10 millisec
`onds, then the switching circuit is rendered operative,
`effectively preventing the output of the subscriber’s
`transmitter from entering the cable system.
`Another prior art solution to the jamming problem is
`available in cable systems utilizing bridger ampli?ers
`with bridger switches that are controllable from the
`headend.
`Bridger ampli?ers connect trunk lines to local feeder
`lines. Within the bridger ampli?er, there is a return
`ampli?er (i.e. a 5 to 30 MHZ ampli?er which propa
`gates signals in the reverse direction). The return ampli
`?er includes a bridger switch that is controllable from
`the headend for disabling the bridger return ampli?er.
`When a jamming signal is detected at the headend,
`succesive bridger ampli?er switches throughout the
`cable system are opened under headend control until
`the jamming signal is eliminated. Then all bridger
`switches are enabled except for the bridger switch cor
`responding to the feeder line containing the jamming
`subscriber unit.
`
`BRIEF DESCRIPTION OF DRAWINGS
`In the Drawings:
`FIG. 1 is a block diagram illustrating a security sys
`tem embodying the present invention;
`FIG. 2 shows the data word format used in the sys
`tem of FIG. 1;
`FIG. 3 illustrates various communication signals in
`the time domain utilized in the system of FIG. 1,
`wherein FIG. 3a is the system clock,
`FIG. 3b is the data word format,
`FIG. 3c is the data frame format,
`FIG. 3d is a Manchester encoded data frame, and
`FIG. Se is the frequency shift keyed (FSK) modu
`lated signal;
`FIG. 4 illustrates the frequency bands from which
`channel frequencies are assigned for the system FIG. 1;
`FIGS. 5 through 9 are table listings of the commands
`used by the headend alarm processor to control the
`respective subscriber alarm processors illustrated in
`FIG. 1;
`FIG. 10 is a table listing the alarm codes transmitted
`by respective subscriber alarm processors in to the hea
`dend alarm processor illustrated in FIG. 1;
`FIG. 11 is a program ?ow chart illustrating the nor
`mal polling and direct verify logic for the program
`embodied in the controller at the headend alarm proces
`sor of FIG. 1;
`FIG. 12 illustrates a typical command sequence for
`normal polling and direct veri?cation transmitted from
`the headend alarm processor, and the corresponding
`respective return sequences received from the sub
`scriber alarm processors for the ?ow chart of FIG. 11;
`FIG. 13 is a program ?ow chart illustrating the
`search verify logic for the program ?ow chart of FIG.
`11;
`FIG. 14 illustrates a typical command sequence for
`the program ?ow chart of FIG. 13; -
`
`40
`
`50
`
`55
`
`60
`
`65
`
`ARRIS883IPRI0001012
`
`

`
`3
`FIG. 15 is a program ?ow chart illustrating the logic
`to ?nd clear channels for the program flow chart of
`FIG. 11.
`'
`
`4,494, l l 1
`
`30
`
`DETAILED DESCRIPTION
`The security system shown in FIG. 1 comprises a
`headend alarm processor 10, a subscriber alarm proces
`sor 12, and a cable TV distribution system 32 which
`provides for two way communication between the hea
`dend alarm processor 10 and the subscriber alarm pro
`cessor 12.
`The headend alarm processor 10 comprises a polling
`transmitter 14, a polling receiver 16, an alarm receiver
`18, and a controller 20.
`The subscriber alarm processor 12 is one of a plural
`ity of similar subscriber alarm processors which com
`municate with the headend alarm processor 10 over the
`cable TV system 32. The subscriber alarm processor 12
`is connected to an extension 34 of the cable system
`though a drop line 36 leading into the subscriber's prem
`ises.
`In operation, individual alarms, e.g. ?re, intrusion
`etc., are received at the respective alarm ports 56. The
`subscriber alarm processor 12 transmits an alarm mes
`sage corresponding to the alarm received at alarm port
`56 through the cable TV system 32 to the headend
`alarm processor 10. After receipt by the headend alarm
`processor 10, the alarm message is forwarded over a
`telephone data link 24 to a central system computer 22
`where the alarm is serviced. For example, the sub
`scriber address originating a ?re alarm would be for
`warded to the appropriate ?re department.
`Alarm messages over the cable TV system 32 are
`provided on three radio frequency signals, i.e. separate
`communications channels. One of the channels is a pol
`ling channel 26 wherein polling messages are sent from
`the headend alarm processor 10. The second channel is
`a polling return channel 28 wherein messages are trans
`mitted from an addressed subscriber alarm processor 12
`for receipt by the headend alarm processor 10 in re
`sponse to a polling message. The third channel is an
`alarm channel 30 wherein any subscriber alarm proces
`sor 12 can initiate an alarm message for immediate trans
`mission to the headend alarm processor 10.
`The subscriber alarm processor 12 comprises a sub
`scriber receiver 38, a subscriber transmitter 40, an alarm
`port encoder 54, and a microprocessor 42 for interpret
`ing polling messages from receiver 38, and providing
`polling response and alarm messages to transmitter 40.
`The microprocessor 42 is also responsive to a control
`console 48 used by the subscriber and connected to the
`microprocessor 42 over a serial data link 47. For exam
`ple,'in addition to providing controls for arming and
`disarming the system, the control console 48 has call
`buttons for police, ?re and medical alert which cause
`the microprocessor 42 to initiate a suitable alarm mes
`sage to subscriber transmitter 40.
`A frequency synthesizer 44 is also provided for set
`ting the frequency of the subscriber transmitter 40
`under control of the microprocessor 42. The subscriber
`alarm processor 12 further includes a programmable
`read only memory (PROM) 46 which contains data
`unique to each respective subscriber alarm processor
`(such as unique subscriber address or special customiz
`ing alarm features). PROM 46 also stores data used by
`65
`the microprocessor 42 to set the original frequencies of
`the polling return channel 28 and alarm channel 30
`through the frequency synthesizer 44.
`
`4
`A battery 52 is provided to back-up the AC power
`supply 50. Battery test logic 49 is also provided for
`monitoring the battery 52 to insure that the battery
`back-up 52 continues to be functional in the event of a
`primary AC power failure. In operation, the AC power
`supply 50 continuously recharges battery 52. If AC
`power fails, battery test logic switches in the battery 52
`to provide power for the subscriber alarm processor 12.
`The system generally operates as follows. The hea
`dend alarm processor 10 polls each of the subscriber
`alarm processors in sequence on the polling channel 26.
`Each respective subscriber alarm processor responds to
`its polling address by transmitting a message on the
`poling return channel 28. Lack of a polling response
`indicates a cut cable alarm.
`If any subscriber alarm processor receives a local
`alarm on an alarm port 56, such subscriber alarm pro
`cessor transmits an alarm message on the alarm channel
`30 essentially when the alarm condition is ?rst detected.
`‘An individual subscriber alarm processor forwards an
`alarm message once on the alarm channel 30 and then
`waits for veri?cation or other instructions from the
`headend alarm processor 10.
`The headend alarm processor 10 upon receipt of an
`alarm message on the alarm channel 30, suspends nor
`mal polling on the polling channel 26. The headend
`alarm processor 10 then directly polls_the subscriber
`alarm processor that originated the message to verify
`the alarm. The addressed subscriber alarm processor
`then transmits its complete address and an alarm code
`on the polling return channel 28. After veri?cation of
`the alarm, the headend alarm processor 10 will forward
`the alarm to the central system computer 22.
`The headend alarm processor 10 has the capability to
`change the respective frequencies of the polling return
`channel 28 and the alarm channel 30, as well as to oper
`ate all subscriber units under battery power for battery
`test purposes, and to search for and verify the sub
`scriber unit that originated a garbled alarm message.
`Messages and commands between the headend alarm
`processor 10 and the subscriber alarm processor 12 are
`exchanged in the form of 8 bit data words. FIG. 2 shows
`the format for the 8 bit words. The two most signi?cant
`bits, B7 and B6, designate either a command code word
`11 (word 3) or an address word 10,01, or 00 (corre
`sponding to word 2, word 1, or- word 0 respectively).
`For word 3 messages, bits B5 through B0 correspond to
`one of 32 possible command codes originating from the
`headend. For word 2, word 1, or word 0 messages, bits
`B5 through B0 correspond to the respective higher
`order 6 bits, middle 6 bits, or lower order 6 bits of an 18
`bit address for each respective subscriber alarm proces
`sor.
`FIG. 3 illustrates the manner in which an 8 bit mes
`sage is transmitted in the present system. The specific
`example illustrated is a command (ALL QUIET) issued
`from the headend to all subscriber alarm processors.
`The ALL QUIET command as well as the other com
`mands utilized in the system is discussed in detail below.
`FIG. 3a is the system clock at approximately 13.985
`KHZ. The system clock is conveniently generated by
`binary division of a 3.58 color subcarrier signal which is
`generated using an available, mass produced color TV
`crystal.
`FIG. 3b represents the command code 367 or 11 110
`111 in binary code. The 8 bits of the command code
`occur in 8 time intervals, T2 through T9 with the most
`signi?cant bit occurring ?rst in time interval T2.
`
`25
`
`35
`
`45
`
`ARRIS883IPRI0001013
`
`

`
`4,494,111
`5
`FIG. 3c shows the data frame format Containing the
`command message. The data frame includes a start bit
`during time interval T1, and odd parity bit during time
`interval T10, and a stop bit during time interval T11.
`FIG. 3a’ is a Manchester encoded signal wherein the
`clock signal of FIG. 3a is combined with the data frame
`signal of FIG. 3c. The Manchester encoded signal is
`generated by an exclusive or logic function between a
`clock (FIG. 3a) and the data frame (FIG. 30). Note that
`the clock and data are now integrated in such manner
`that there is a waveform transition in the middle of each
`bit interval. An upward transition (from logic 0 to logic
`1) in the middle of a bit interval indicates a logic 1,
`while a downward transition (from logic 1 to logic 0)
`indicates a logical 0.
`FIG. 4e illustrates the actual signal encoding of the 8
`bit word on the cable TV system. FSK modulation is
`used wherein a logic 1 corresponds to plus 75 KHZ
`above center frequency and logic 0 corresponds to
`minus 75 KHZ below center frequency. When the en
`coded data (FIG. 4d) is at a logical l, the FSK signal
`(FIG. 4e) is of a ?rst, higher frequency, and when the
`encoded data is logic 0, the F SK signal is of a 2nd lower
`frequency. The transition of the encoded data between
`0 and l (and vice versa) is shaped to provide a smooth
`gradual transition so that the signal transitions of the
`FSK signal between high and low frequency is also
`relatively gradual. This premodulation wave shaping
`tends to prevent an unduly broad spectrum spread for
`the FSK signal.
`With regard to communication channel frequency
`and bandwidth, reference is made to FIG. 4 which
`illustrates the preferred channel assignments to be used
`with the present system. The polling channel frequency
`is chosen from any conveniently available frequency in
`the standard FM band, i.e. from 88 to 108 MHZ. An
`unused space in the FM band can be found in most
`localities. Based on the system clock frequency and the
`difference between upper and lower FSK frequencies, a
`bandwidth of 400 KHZ at 40 db is anticipated.
`The polling return channel and alarm channel fre
`quencies are chosen from the T-9 video channel (17.75
`to 23.75 MHZ) in the return spectrum. Again, band
`width of the polling return channel and alarm channel
`are expected to be 400 KHZ at 40 db. Note that while
`the polling channel frequency in a given system is gen
`erally ?xed, the polling return channel and alarm chan
`nel frequencies are selectable by headend command, as
`will be more clearly understood from the following
`detailed description of system commands.
`
`6
`ALL STAND ALONE command causes each sub?
`scriber alarm processor to sound local alarms only on
`the subscriber’s premises but not to transmit alarms on
`the alarm channel. The ALL STAND ALONE com
`mand is distinguishable from the ALL QUIET com
`mand in that the ALL STAND ALONE command
`causes the last alarm condition received to be stored
`while the ALL QUIET command causes the ?rst alarm
`condition received to be stored.
`ALL SPEAK AGAIN command causes all sub
`scriber alarm processors to transmit stored alarms again
`over the alarm channel. This command essentially can
`cels the ALL QUIET command and/or the ALL
`STAND ALONE command. Generally, regardless of
`whether or not a previous command was issued, the
`ALL SPEAK AGAIN command requests all sub
`scriber alarm processors in the system to retransmit
`their stored alarm condition, if any, on the alarm chan
`nel.
`RESTORE ORIGINAL FREQUENCY command ,
`causes all subscriber alarm processors to set the frequen
`cies of the polling return channel and alarm channel to
`respective values as de?ned by data stored in the
`PROM of each respective subscriber alarm processor.
`BATTERY TEST ON is used for a global battery
`test. Upon transmission of the BATTERY TEST ON
`command, all subscriber alarm processors switch over
`to battery power. The global battery test provides for
`actual operation of each subscriber’s battery under sim
`ulated power fail conditions. The battery test is contin
`ued for a speci?ed time duration (eg, 1 hour). If any
`battery failed during the test, the low battery alarm is
`transmitted from the respective subscriber unit to the
`headend. A local low battery alarm may also sound at
`the subscriber’s premises indicating that the battery
`should be replaced. A battery failure during the global
`battery test causes the respective subscriber alarm pro
`cessor to switch back to AC power, so that there is no
`interruption in security coverage. A battery that passes
`the global battery test therefore has a demonstrated
`capability to power the subscriber’s unit for the speci
`?ed time duration in the even AC power fails.
`BATTERY TEST OFF command indicates to all
`subscriber alarm processors to terminate the global
`battery tests and return to normal AC power operation.
`RESET is global command for resetting all sub
`scriber alarm processors to a predetermined initial state.
`
`15
`
`30
`
`45
`
`50
`
`GLOBAL COMMANDS
`Global commands, shown in FIG. 5, have a format
`consisting of a single word 3 message.
`INTER-RECORD GAP (IRG) is used as a system
`synchronizing signal. Both the headend alarm processor
`and the subscriber alarm processor may preceed a mes
`sage transmission by transmitting 5 IRG codes.
`ALL QUIET command causes all subscriber alarm
`processors to stop all upstream transmission on the
`alarm channel unless otherwise requested by another
`headend command. If an alarm condition existed prior
`to the ALL QUIET command, such alarm is stored for
`later transmission, or if no alarm was received prior to
`the ALL QUIET command, then the ?rst alarm re
`ceived after the ALL QUIET command is stored for
`later transmission.
`
`55
`
`65
`
`ADDRESSABLE COMMANDS
`Addressable commands shown in FIG. 6 have a for
`mat consisting of a word 3 command code followed by
`word 2, word 1, and word 0 which de?ne an 18 bit
`subscriber address.
`POLLING command polls individual addressed sub
`scriber alarm processors. The addressed subscriber unit
`acknowledges the polling command by transmitting the
`word 0 portion of its address on the polling return chan
`nel. There is an alternate format for this command
`which increases the polling speed. The alternate format
`consists of a single word 0. In such case, a subscriber
`alarm processors utilize the previously transmitted
`word 2 and word 1 as the upper 12 bits of the address
`polled.
`‘ DIRECT VERIFY command requests the addressed
`subscriber alarm processor transmit an alarm message, if
`any alarm condition is stored, on the polling return
`channel. The format of the alarm message in response to
`a direct verify command is 5 IRG, word 2, word 1,
`
`ARRIS883IPRI0001014
`
`

`
`4,494, 1 1 1
`
`7
`word 0, followed by an alarm code indicating the type
`of alarm condition, and a checksum. This command is
`typically used to directly verify that an alarm received
`on the alarm channel did, in fact, originate at the ad
`dressed subscriber unit.
`ALARM VERIFIED command clears the alarm
`storage of the addressed subscriber unit in order to
`permit that subscriber unit to process a new alarm. The
`ALARM VERIFIED command is typically used to
`clear an alarm condition after the alarm has been re
`ceived and direct veri?ed from the headend.
`DISARM command turns off the intrusion alarm of
`the addressed subscriber unit.
`LEARN PRIMARY CODE command, intended as
`an added level of access security, this command autho
`rizes the subscriber to enter a new primary code. The
`primary code is used to program secondary codes for
`use by others. Programming of a new primary code is
`enabled only by this headend command.
`
`8
`FIG. 9 shows a global data command with a three
`word format. The ?rst word identi?es the command,
`the second word is either a word 2, word 1, or word 0
`de?ning a 6 bit portion of an 18 bit address, and the
`third word is a data word X.
`GROUP TUNE POLLING RETURN CHANNEL
`command causes all subscriber units having an address
`that matches the following address word (word 2, or
`word 1 or word 0) to tune their respective polling re
`turn frequency to the following word X.
`FIG. 10 is a table listing of the 8 _bit alarm codes
`corresponding to various alarm conditions. Alarm ports
`0 through 7 are indicated in their order of priority.
`Alarm code 0, the highest priority, indicates an intru
`sion alarm. Alarm code 1, the second highest priority,
`indicates a ?re alarm. The next 6 codes in order of
`priority are de?ned by the user. Alarm codes 20, 40 and
`100 correspond to medical, ?re and police panic button
`alarms. Alarm code 200, 272 and 274 correspond to
`battery failure, tamper alarm and system disarm condi
`tions respectively.
`-
`The program ?ow chart in FIG. 11 illustrates the
`normal polling and direct verify logic carried out by the
`headend alarm processor 20 (FIG. 1). In the following
`description, FIG. 11 is discussed in conjunction with
`the system block diagram of FIG. 1.
`The program is entered in step 100 wherein the pol
`ling return and alarm channel frequencies are monitored
`to determine whether such channels are clear. A conve
`nient criteria for deciding as to whether the channel
`frequencies are clear is to monitor the receiver squelch
`of respective polling receiver 16 and alarm receiver 18.
`If the respective squelch function is continuously open,
`then the respective channel is considered to be not clear
`indicating that a subscriber unit or other signal source is
`jamming that frequency.
`If both the polling return frequency and the alarm
`channel frequency is clear, a polling command is sent to
`a subscriber address at step 104. If no polling response is
`received at st