Note: Descriptions are shown in the official language in which they were submitted.
1 FIELD 0~ ~HE INVE~TION
This inventioll relates to security alarm sy~tems ~hich
include monitoring alarms for fire, smoke, intrusion, appli-
ance operation and the like.
BACKGROUND OF THE INVEN~IO~
Security alarm systems are becoming increasingly popular
in residential communities. Ilhe most common form of sensor in
residential areas and homes is -the form of fire and smoke de-
tector. However, -there has been increaaed use in reside~tial
areas of intrusion or burglar alarms and also devices which
monitor the status of various appliances in the home 9 whether
it be a gas-fired water haater, gas-fired furnace, free~ers
and the like. Similar alarm systems are, of cour~e, used in
industryO As the sy~tems are e~panded at each installation,
it becomes more and more important to have a central monitor-
ing device which determines the status of all of the sensors
to ensure that they are operative at all times and which is to
be located in an area such that, when an alarm is sounded,the
type of alarm and its whereabouts can be det~rmined.
This hAs resulted in the demand for a central monitor
which can communicate ~ith all forms of sen~ors in a home or
industrial installation. To accomplish this ob3ective, trans-
mitters have been devised for coupling with the various sen-
sor~ and transmitting information to a receiver of a central
monitor sy~tem. ~he information transmitted may identify the
type of alarm and its location~ In industrial applications,
radio transmitters are not frequently used, because it is easy
to install wiring to hook up the various sensors directly with
the central monitor system. Ho~ever in the home, wiring is
unattractive and with the use of radio receivers and trans-
~.~
~ ~o~
1 mitters, the wiring is eliminatedO
In residential applications, it i~ important to disting
uish the security alarm system o~ one household relative to
all ad,jacent households~ ~lhis pr~vents a transmitter in one
household transmitting fln alarm condition and having it picked
up by the neighbouring household alarm system. To avoid this
each transmitter i~ coded with in~ormation, l~hich not only
identifies the particular alarm system, but also the sensor
which is transmitting the alarm. This require~ that some form
of memory be provided with each transmitter and with the re-
ceiver~ Presently this has been accomplished by use of a mem-
ory which is precoded before the unit is sold, offering little
~lexibi~ity to the householder or by use of memories which may
be coded by mechanically flipping switches. By using a prede-
-termined format, the code ~or the system can be entered intG
the device by ~lipping the appropriate switches along with a
code for the particular sen~or being coupled with a tran~mit-
ter. Such preprogramed or limited mechanical switching pro-
gram memories of~er little flexibility and to the average con-
sumer are difficult to program. Since the pro~ram is providedby way of switches; they can be accidentally altered or could
be intentionally altered by an intruder into a household. In
addition, the tramsitters normally have their o~n power supply
which is ~eparate from the sen~or. It usually involves locat-
ing the transmitter outside of the sensor, adding to the bulk-
iness of the overall system and detracting from the attract--
iveness o~ the various sensors which are visible, such as the
smoke and perhaps the intru~ion detectors.
The improvements in security system~, according to thi3
invention, overcome the above problems in providing a far more
1 flexible syste~ to accommodate variations oP each household
and which can be read:ily installed by the con~umer.
SU MARY OF THE IWVRRTION
In most ~scurity alarm ~y~tem~, there are a plurality
of sensors for one or more of fire, ~moke, intrusion, appli-
ance operation and the like. A central monitor d~vice moni~
tors and i9 capable of perceptibly indicating the ~tatus of
each of the sensors. Individual tran~mitters are provided for
each of the sensors for transmitting information from a re-
spective sensor to a rec0iver associated with the central mon-
itor. The central monitor proces~es the transmitted infor-
mation to indicate perceptibly the status of the respective
sensor causing tran~mission of the information. A memory is
associated ~ith each transmitter and with the receiver for
storing information. This enables the monitor to recogni~e
information transmitted by a respective transmitter of its
system, as actuated by a corresponding sensor, to identify the
3tatus of the sensor. The improvement, according to this in-
vention, comprises electronic means for loading information
data into an electronic memoxy for each of the transmitters
and into an electronic memory associated with the receiverO
Each tran~mitter has electrical coupling means for electric-
ally connecting the transmitter to the data loading means.
The transmitter is ~eparable from the data loading means after
completion of loading the desired identification information
data into the electronic memory. Thi~ preclude~ altering the
information data 3tored in the electronic memory.
The data loading means may be a keyboard to ~acilitate
manual entry of the prede-termined information. The data load-
ing means is adapted to process the information entered via
~ ~$~3
1 the Xeyboard and convert it into data which i9 loaded into therespective electroni.c memory for the transmitter and the re
cei~er. The dRta loading means may be a component of the mon-
itor, where the monitor has an elect:ricnl coupler compatible
with the electrical coupler of each transmitter to pro~ide for
electrical communication between the respective transmitter
and the data loading means, In this instance, the data load-
ing means may be adapted to load at the same time the informa-
tiOII into both the respective transmitter memory and the mem-
ory associated with the receiver to avoid errors in loadinginformation into the memories of the transmitter and receiver.
This ensures that the proper information of the sensor i~
transmitted and recogni~ed by -the receiver of the monitor
The transmitter then, for use in associ.ation with the
security alarm system has a programmable electronic memory and
an electrical co~lpling means for electrical connection to an
electronic device ~or loading information into the program-
mable electronic memory.
To facilitate use of a transmitter with e~isting sen-
sors, the transmitter is adapted for insertion between anelectrical coupling to or terminals of a power supply for a
corresponding alarm sensor and the power supply leads to the
alarm sensor. The transmitter has means for sensing e~cess-
ive power drawn by the alarm sensor when the alarm goes into
an alarm state. 'rhe power sensing means activates the trans-
mitter when there is an alarm, to indicate the alarm by trans-
mitting the coded information in it~ memory for identifying
itself to the central monitor.
The -transmitter may be provided with a t~mporary power
~0 supply to power -the electronic memory of the -transmitter once
o~
1 disconnected from the data loading means until the transmitter
is connected to the power supply of the alarm sensor~ The
transmitter includes an electrical connector device to permit
connection with the means for loading the ideIItification
information data into the electronic memory of the tran~mitter
and permit discon.nection. ~he transmitter may also be
equipped with a battery voltage sensor to determine when the
battery voltage has dropp0d at steady state below a predeter-
mined lavel. Such device actuate~ the transmitter to signal
the central monitor that the power ~upply of the particular
battery powered sensor i~ low to notify the need for-battery
replacement.
B~IE~ DESCRIPTION OF THE DRAWI~GS
Preferred embodiments of the invention are shown in the
drawings, wherein:
~ igure 1 is a schematical representation of a security
alarm system having a plurality of ~ensoræ and a central moni-
toring ~ystem. A transmitter i9 associated with each 3ensor
which is adapted to transmit information to a receiver of -the
central monitor system;
Figure 2 is a schematical representation of the use of
an electronic keyboard for loading identification coding in-
formation into the memory of the transmitter a~sociated with
each sensor;
Figura 3 is a æchematical representation of the use of
th0 keyboard of Figure 2 for loading information into the mem-
ory associated with the receiver of the central monitoring
~ystem;
Figure 4 is a peræpective view of the keyboard;
~Q Figure 5 is a perspective view of the component form of
1 3
1 the transmitter which is adapted for insertion between the
power supply for and the electrical leads to the particular
~ensor;
Figures 6a through 6e ~chematical].y represen-t the ~tor-
age format in the memory of the transmitter and the string of
output of data when the transmitter is activated;
Figure 7 i9 a block diagram of the central monitor and
receiver network; and
Figure 8 is a block diagram of the tran~mitter~
DETAILED DESCRIPTIO~ OF THE PREF~RRED EMBODIME~TS
It i8 appreciated that there are many tran~mitter and
receiver components available which may be operated by way of
integrated circuit chips to provide compact units. ~igure 1,
thereforel schematically repre~ents the transmitter and re-
cei~er in the central monitor ~ystem where it is understood
for sake of illu~tration that the transmitter~ are 3hown as
large blocksO In Figure 19 the ~ecurity alarm system 10 com-
pri~es a central monitor 12 and a plurality of ~ensors 14, 16,
18 and 20. Each sensor i~ speci~ic to fire, window entry~
door entry and detection of high water level in a basement
sump area. Obviou~ly there are many other application~ for
~ensors, particularly in the household~ for sensing the status
of appliances ~uch as free~ers and refrigerator~ and the sup-
ply of gas to gas-~ired water heater~, to gas-fired furnaces
and the like. Associated with each of the sensors is a
specific trans~itter 22, 24, 26 and 28.
~ or purpose of 1llustration~ each tran~mitter is elect-
rically connected to the sensor by way of electrical leads 30.
The central monitor 12 includes a cabinet 32 which may include
a visual di~playO ~he cabinet houses a receiver for -the
~.~a~l3
1 tr~nsmitters 22, 24, 26 and 28. The central monitor can ~ctu-
ate an outside horn ~4, a telephone dialer 36, a voice synthe-
sizer 3~ and a trouble indicator ~0~ Sen30r 14, upon ~en~in8
smoke in a room, actuates the transmitter 22 to signal the
central monitor 12 and the appropriate a~arm or c~ll is made.
Similarly the opening of window 42 and door 4~ are
detected by contact switches to actuate the transmitters 24
and 26, where the signal as received by the central monitor
actuates the appropriate alarm. With the detector leads 46
i~ the sump area 48, a high water level is detected to actu-
ate sensor 20 and in turn cause the transmission from trans-
mitter 28 to signal the central monitor and cauee a trouble
alarm at 40. Each of the transmitters 22, 24, 26 and 28 has
an electronic memory which stores the particular coded infor-
mation to identify the sensor that the transmittar is associ-
ated with and to provide a code which identifies the alarm
system that the transmitter belongs to. As can be appreci-
ated, the central monitor system must be able to recognize
only its own transmitters and not those of some other
building. Thus, each transmitter memory is loaded with a
code to identi~y the system.
The particular format of the in~ormation stored in the
electronic memory o~ each transmitter is illustrated in Figure
6a. Bits 1 through 7 are reserved for storing in Binary form
the system identification number which uniquely identifies the
central monitor system that the transmitter belones to. The
seven bits of information can uniquely identify up to 128 dif
~erent systems and 7 therefore 9 with a judicious selection of
a system identi~ication number9 interference from neighbouring
systems will be eliminated.
~ ~ 8~1 3
lBits 8 through 19 are reserved for describing the type
of sensor and its characteristics. In particular, bits 8
through ll identify the description of the sensor suoh as
sensors for fire, window or door entry, and high water level
detection. Up to sixteen types of sensoIs can be described
by the sensor description field. In a large building, it is
desirable to have more than one of any particular type of
sensor. For e~ample, it rnay be desired to have a fire .sens-
ing device in each room of the house. ~herefore, bit fields
lO12 through 15 and 16 through l9 are reserved for indexes and
subindexes specifying the particular sersor's loc~tion. The
sensor location index field may be used to uniquely identify
up to sixteen locations in the systems purview. Each of these
sixteen locations may be further broken down into another si~-
teen sub locations by the sensor location subinde~ field con-
tained ~n bits 16 through l9. It will be appreciated that the
sensor description codes and .sensor location inde~ and sub-
inde~ codes may either be predetermined or as~igned a specific
meaning to be interpreted by the monitor at the time of
loading the information into a particular transmitter memory.
In order to load the information into the transmitter,
as shoNn in ~igure 2, a portable handheld keyboard 50 is u3ed
which has a visual display 52 and keys 54. ~he keyboard has
an electrical couyling 56 at the end of it~ electrical lead
58, which is connectible to the transmitter 28~ Information
can be loaded into the memor7 of the transmiter 28 by pressing
the appropriate keys of the keyboard 500 ~he keyboard 50 may
include a microprocessor to process the information being
entered on the keys and displayed at 52 to convert it into
properly coded information which is storable in the memory of
1 transmitter 28.
Figure 4 shows the keyboard 50 in greater detail with
the electrical coupler 56 having metal prong~ 60 which are
adapted to fit in the appropriate recepticle of' the tran~mit-
ter. Figure '7 ~how~ electrical lead 58 comprising two infor-
mation carrying wire~ 80 and 82. Wire 80 carries one of the
bits of data that is to be loaded into the transmitter memory
84 of Figure 8 and wire 82 carries a clock pul~e for synchron-
ization purpose~. As can be ~een in Figure 8, the transmitter
is equipped with a recepticle 80 to accept the electrical
coupler 56. Data on line 80 i9 transferred to line 88 in the
particular transmitter and the data on line 82 i8 transmitted
to line 90 in the particular transmitter. The nineteen bits
of information comprising the system identification number,
sen~or description, sensor location index and sensor location
subindex are sequentially down loaded into the memory 84 of
the transmitter. The-keyboard 50 is disconnectible from the
transmitter after the information is loaded into the memory
of the transmitter. Thus the information coded in the trans-
mitter cannot be altered unless it is recoupled with the key-
board 50. Thi~ prevents altering of the information loaded
into the transmitter to avoid errors and mishaps and also to
prevent intruders, such as burglars 9 modif`ying the program
before an alarm can be sounded.
As suggested in Figure 3, the keyboard 50 can in actual
f`act be an integral component of the central monitor system
and remain with the central monitor. ~he central monitor can
be provided with appropriate coupler to permit hook up of the
transmitter which is to be loaded with information to the
central receiver and then by use of the keyboard, load the
1 3
l necessary information into the respective tran~mitter.
If the keyboard is alpha-numeric, then the information
to be entered on the keyboard may read as follows: "~mi-th"
to identify the system identification number; "Water Sump" to
identify the sensor description; "~urnace Room" to identi~`y
sensor location; and a sub~location nams if so desired. The
keyboard is adapted to process such information and convert
it into data which is loaded into the corresponding memory 84.
When the sensor leads ~6 sense a high water level, the trans-
mitter 28 is actuated to transmit this information. Thereceiver, upon receiving the initial code of the transmission,
recogni3es the transmitter 28 as one of its system and pro-
cesses the transmitted information to actuate the trouble
alarm 40. Similarly with transmitters 22, 24, and 2~, the
keyboard 50, as shown in dot in each instance, may be used to
load the appropriate information into the electronic memory
of each of tho~e transmitter~
It will be appreciated to those skilled in the art that
many possibilities e~ist for the sequence and type of in-
structions accepted by the keyboard unit. It may bedesirable to have a "high level" type of communication with
the keyboard as previously discussed. That is to say, full
textual descriptions of the system identification number,
sensor description, sensor location index and sensor location
~ubindex may be used. ~his type of coding is readily under-
stood by the avera~e consumer, however, as will be appreci-
ated, leads to more complicated processing requirement~ in
ei-ther the keyboard or central monitor than may be economicalO
A le~s complex, but easy to use encoding system may be
as follows. Any number between l and 128 may be used for the
413
l sy~tem identification number. For the sensor description,
various codes may be preassigned, such as l for fire ~ensors,
2 for window en-try sensor, and so on. Similarly, for -the
sensor location index, l may identi~y the basement, 2 may
identi~y the attic and 90 on. The con~umer would be left to
attach a particular meaning to the sensor location subindex
codes which may rsng0 from l through 16. The system identifi-
cation number need only be entered oncey if the keyboard is an
integral component of the central monitor system. The micro-
processor of the central monitor would be adapted to automat-
ically load the system identification number into each trans-
mitter memory when the transmitter is being loaded with data.
In any event, when loading information into the memory of a
particular transmitter, the sensor description, sensor
location index and sensor location subindex codes must in-
dividually be specified. During loading of a particular
tran3mitter's memory, the display on the keyboard prompts the
user with the ne~t code to be entered. After all the codes
are entered the display on the keyboard responds with the
codes entered and an opportunity for verification i5 afforded.
The codes are then processed into the format illustrated in
Figure 6a and loaded into the memory 84 of the particular
transmitter .
The central monitor system 12 must also have a memory
92 to hold associated information indicative of ~hat has been
loaded into the transmitters. The keyboard 50 is used to
load into the central monitor system 12 all of the pieces of
information identifying the various transmitters 22, 24, 26
and 28, along ~ith the identification number for the system.
If the keyboard is an integral component of the central
~ ~û4~ 3
1 monitor sy~tem, it wlll be appreciated that the memory 92 of
the monitor system i9 loaded with the appropriate information
simultaneou~ly with the loadin~ of the informa-tion lnto the
memory 84 of a particular transmitter.
Figure 8 ~how~, enc]osed in dot, a transmitter such aa
transmitter 22. External to the transmitter is a power supply
62 which i9 conneoted through leads or terminal~ 64 and 66
to tarminals 94 and 96 of the transmitter. Power internal to
the transmitter i9 designated by numeral 98. ~erminals 72 and
74 are provided on the transmitter to power a particular
sensing device 100 through leads 68.
Memory 84, which has been previously discussed~ is a
shift register capable of holding 19 bits of information. A
clock input 102 shift~ data one position to the right a~ in-
dicated by arrow 104 upon each clock pulse. A bit of data
enters the shift register memory at 108 and e~its at 110. A~
information i~ loaded into the memory 84 from the keyboard or
central monitor, data enters on line 88 and synchronizin~
clock pulses enter on line 90. The information on lines 88
and 90 are OR'd through gate~ 112 and 114. Therefore, the
binary string of information, as indicated in Figure 6a, is
sequentially clocked into memory 84. ~he electrical coupler
56 i9 then disconnected from connsctor 80 and thereafter the
information stored in memory 84 is non-alterable~
After the coupler 56 is di~connected from connector 80,
the transmitter iB moved to its appropriate location and
connectsd between power supply 62 and sensor 100. In sit-
uations where the transmitter is programmed away from the
sensor power supply 62, the optional power supply l~ads 6~,
~0 65 from the k~yboard 50 are coupled to the transmitter
12
~ ~ 8 ~ 3
1 ~ockets g4 and 96 to power the transmitter while being pro-
~rammed. When the programming iæ complete, the power leads
63, 65 are di~connected. A capacitor 116 of sufficient cap-
acitance is connected acrosæ the power supply terminal~ in
order to maintain æufficient voltage in the tran~mitter and
in particular memory 84 so that it does not loo~e the informa-
tion that has been loaded into it prior to connection of the
transmitter to power supply 62.
A status register 118 i~ provided in the transmitter to
hold 6 bits of information indicative of the s$atus of the
sensor. One bit of the status register is connected to a low
voltage detector which indicates when power supply 62 is below
a predetermined threshhold levelO Another bit of the status
register i9 connected to a current sensor 122. If sensor 100
is of a certain type, upon an alarm condition being detected,
it will draw an amount o~ current above normal~ Current
sensor 122 is adapted to sense this increase in current drain
and thereby detect an alarm condition in the ~enæor 100. The
remaining four bits of statuæ register 118 are connected
through line~ 124 to æockets 126 in the side of the tran~mit-
ter. For a sensor 100 having outputs indicative of a partic-
ular ætatus, lines 12S æhown in dot, are connected to socketæ
126 thereby transferrine the information to the associated
bitY of thP status register 118. The six bits of information
of the status register 118 are shown in field format in Pig-
ure 6b.
Upon a status condition being sensed in status register
11~, the information in the transmitter i9 transmitted. Ac-
cording to this embodiment, the information is transmitted at
radio-wave frequenc~ through air. It is understood, however,
1 the information may also be transmittsd through air by using
other forms of electromagnetic radiation, such as ultra-sonic
and infra-red. In addition, the signal may be tranami-tt0d
through the existing household wiringO Thefra~le generator
130 CreQtes a binar~ stream of information, w'hich is output
there~rom on data line 132 and clock line 134. The frame
generator concatenates a unique deliminator flag, as shown in
Figure 6c, the in*ormation stor~d in memory 84, as shown in
Figure 6a 9 and the information stored in status register 118,
as sho~n in Figure 6b, into a string, as ~hown in Figure 6d.
To effect this concatenation, the information stored in memory
84 is clocked from output 110 into the frame generator and
thereafter reinserted into the memory 84 through input line
108 thereby restoring memory 84 to its original condition.
The bit stream as e~emplified in Figure 6d, is cyclic-
ally repeated until the information in status register 118 is
cleared by the alarm condition being corrected. q'o comply
with the regul~tions of certain communication authorities, the
repetition of the bit stream is randomnized. '~he repeating
bit stream is fed down data line 132 with clock pulses being
provided on line 134. Sync pulse generator 136 adds R synch-
ronizing pulse to the bit stream and has an output 138. As
representatively shown in Figure 6e, each downgoing edge of
the wave form serves as a timing edge for the receiver to
synchroni~e witho If a 1 is to be represented in the bit
frame, the sync pulse generator gener~tes a high level shortly
following the down going sync pulse. If a 0 is to be repre-
sented, -the level does not go high as soon.
~'he ~ignal on line 138 is then fed to a frequency shift
key (FSK) modulator 140. I'he output from the FSK modulator
14
1 appears on line 142 and, in accordance with the signal on line
138, varies between 11 kilohert~ and 9 kilohert~. This ~ignal
is then fed to transmitter 144 which amplitude modulate~ the
signal at a carrier frequency of 300 million hert~. In order
to comply ~ith csrtain communication regulatory authorities,
the field strength output by the transmitter should be limited
to less than 6,000 microvolts per meter at 3 meters. The
-transmitter receives a control signal on line 146 from the
frame generator to turn the tran~qmitter on only when the frame
generator is cyclically repeating the bit ~tream.
As shown in ~igure 5, a transmitter, such as transmitter
22 ? i.S very compact compared to the si~e of the usual battery
power supply 62 for a fire/smoke detector or intrusion de-
tector. ~he nine volt batory includes the usual male terminal
64 and female terminal 66 which mate with transmitter termin-
alæ 94 and g6 as may be ~een in E'igure 80 ~he electrical
leads to the sensor are encased in wire coating 6~ and, al-
though not ~hown, the underside of tab 70 includes the male
and female terminals which mate with the corresponding termin-
als on the battery. 'rhe tran~mitter i3 inserted between thelead 68 to the sensor and the power ~upply. ~hus the trans-
mitter i~ provided with two sets of male and female terminals
72 and 74. The s:ide of the transmitter includes the connect
pin arrangement 80 and 82 which permits connection of the
transmitter to the connect coupler 56 of the keyboard to per-
mit loading of information into the memory of the tranqmitter
22.
With this arrangement, it is apparent that the transmit-
ter may be simply inserted between the power supply and the
lead~ to the sensor without adding substalltially to the bulX
4 :~ ~
1 of the system. This permits users, particularly hou~eholders,
to insert the transmitter into existing sensor housings with-
out having to alter or replaco their existing units.
With reference to Figure 7, receiver and demodulator 148
receives the signals transmitted by the various transmitters
The modulator uses the down going edges of the pulses intro-
duced by sync pulse generator 136 to decode the received
signal and output a ~ignal on line 150 which corresponds with
the bit stream produced by frame generator 130 in a particular
transm:itter. The demodulated signal is then proces~ed by flag
recognizer 152 which searches for the unique deliminstor flag
sequence as illustrated in ~igure 6c. Upon recognition of
this flag bit pattern, the following 25 bits of information
are separated from the received stream and passed down line
154 to bit stream comparator 156. The 25 bit~ of information
contain the system identification number, sensor description9
sensor location index, sensor location subindex and sensor
status transmittsd by a particular transmitter. This informa-
tion is stored in the bit stream comparator 15~.
It will be appreciated that many transmitters from
either one security alarm system or neighbouring systems may
tran~mit simultaneously and thus result in broadcast congest-
ion and collisions which result in an erroneous signal being
recei~ed, Since each transmitter in either the security alarm
system itself or neighbouring systems transmits synchronously
and with periods of random length between the repeated *rames,
it i9 neces~ary to en~urs that the in~ormation passed on by
the flag recognizer 152 is correct. Many erron~ous recapt-
ions due to oYerlap ~ill be eliminated by the flag recognizer
152, but the possibility still exists for error in the
~ ~8~
1 subsequent 25 bits of information. Since the transmitters
randomly repeat the f'rame of informat:ion being -transmitted,
it is possible to compare several transmis~ions and determine
their correctnass~ To this effect, bit stream comparator 1S6
stores the most recent ten 'bit streams pas~ed on by fl~g
recogn,izer 152. If a matching pair of bit streams can be
found in the mo~t recent ten bit ~treams received, it is as-
sumed that the transmission is correct. A copy of the matched
bit stream is passed down bus 158 to a microproce~or 160
which is the principal par-t of the central monitor 12.
~ he microprocessor checks the first seven bits of the
bit stream received and determines if the information therein
corresponds to the ~ystem identification number which has pre-
viously been stored in memory 92 of the central monitor 12.
If the received sy~tem identification number corresponds to
the stored system identification number, the remainder of the
received information is processed and the correct response in~
itiated. The sensor description, sansor loation inde~ and
sensor location subindex and sensor s-tatus is compared with
the information stored in memory 92 and depending upon pre-
determined crite-ria, the appropriate alarm or alarms are act-
uated according to a predetermined response. ~he alarms in-
clude an outside horn 34, a telephone dialer 36, a voice
synthesi~er 38 ~nd a trouble indicator 40. The home o~ner is
alerted to the sensed alarm condition and appropriate cor-
rective action may then be taken~
Although variou~ preferred embodiments o~ the invention
have been described herein in detail, it will be understood by
those skilled in the art that variations may be made thereto
without departing from the spirit of the invention or the
scope of the appended claims.
17
