Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND SYSTEM FOR COMMUNICATING CALLER IDENTIFICATION INFORMATION BETWEEN
A REMOTE SITE AND A CENTRAL MONITORING STATION OVER PSTN
TECHNICAL FIELD
The present invention relates to communications and in particular to a
method and system for passing information and caller identification between
independent parties over a public switched telephone network.
BACKGROUND ART
Public switched telephone networks (PSTNs) have been commonly
used to establish telephone calls between communicating parties. With the
advent of
modems, PSTNs have also been used to allow electronic equipment at remote
sites,
such as for example, security panels, vending machines, environment monitoring
systems, meters, and load management systems, to send information to a central
location or clearing house.
Currently, in the latter case, when electronic equipment at a remote site
is to send information to the central location, the modem at the remote site,
goes off
hook and dials the telephone number assigned to the central location. When the
call is
answered, the electronic equipment at the remote site sends the information
electronically over the PSTN to the central location. Once the information has
been
' sent, the modem at the remote site hangs up to terminate the call.
Typically, the central location receives information from electronic
equipment at a significant number of remote sites. Often, a plurality of
remote sites
call into the central location at the same time. In order to handle multiple
calls, the
central location is connected to the PSTN via a number of telephone lines,
each having
an associated modem and telephone number. If a modem at a remote site dials
the
telephone number assigned to one of the modems at the central location and~a
busy
signal is received, the modem at the remote site hangs up and tries the
telephone
number assigned to another one of the modems.
In some countries, call charges apply whenever a remote modem makes
a connection with a modem at a central location. Also, long-distance charges
may
apply if the central location is situated in a different geographical location
than the
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remote site initiating the call. Even though electronic equipment at remote
sites often
send short information messages, telephone charges can still be substantial if
the
messages are sent on a regular basis, and especially if the messages are sent
over a
wireless communication network.
Security systems for both residential and commercial applications have
gained wide acceptance and central monitoring of such security systems is
typically
recommended. As a result, many security systems connect to a central
monitoring
station over a PSTN when an alarm condition arises to relay the alarm
information to
the central monitoring station.
Security systems of this nature typically include a number of sensors to
monitor the area under surveillance. The sensors communicate with an on-site
alarm
panel that acts as a central source for the sensors. The alarm panel connects
to the
central monitoring station over a PSTN when an alarm condition occurs, and
relays the
sensor information to the central monitoring station. The central monitoring
station in
turn processes the sensor information and based on the processed information,
takes or
initiates certain predetermined steps. These steps may include producing an
operator
report and/or contacting the local police department, fire department or
private
security personnel. Of course, the steps to take in response to sensor
information can
vary depending on the needs of the customer, the owner of the alarm panel
and/or the
assessment of the alarm condition made by the operator at the central
monitoring
station.
In modern PSTNs, caller line identification (CLI) data is often
transmitted to locations receiving incoming calls. CLI data is particular to
each
subscribed telephone service and typically contains the telephone number of
the calling
party, alpha-numeric identification of the calling party, and the time and
date of the
call. Of course, other information may also be provided. Security systems,
which use
CLI data accompanying a call, have been considered.
For example, U.S. Patent No. 5,511,109 to Hartley et al discloses a
security system using call display. The security system includes a plurality
of alarm
panels, each of which is associated with a plurality of sensors. The alarm
panels are
connected to a PSTN via telephone lines. A receiving arrangement is connected
to the
PSTN and recognizes calls generated by the alarm panels. The receiving
arrangement
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is also connected to a central computer. When an alarm panel generates a call
in
response to an alarm condition as detected by one or more of its associated
sensors,
the PSTN supplies CLI data identifying the calling alarm panel. The receiving
arrangement in turn answers the call allowing the alarm panel to send alarm
S information to the central computer. The CLI data supplied by the PSTN
together
with the alarm information received from the alarm panel is used by the
central
computer to determine the steps to take in response to the alarm condition.
Unfortunately, this security system can be costly to customers if long
distance
telephone charges apply to the call made by the alarm panel or if the call
made by the
alarm panel is carried out over a wireless communication network where airtime
charges apply.
Canadian Patent Application No. 2,214,525 to Drysdale et al discloses
a system for monitoring the integrity of a telephone connection between an
alarm
system and a central location established over a PSTN. The alarm system
includes a
digital communicator for establishing a call to the central location at
predetermined
intervals or in response to polls made by the central location. If no alarm
condition
exists when a call is to be made to the central location, the digital
communicator drops
the call after CLI data has been transmitted to the central location. This
allows the
central location to confirm the integrity of the telephone connection to the
alarm
system without having to answer the call. If an alarm condition exists when a
call is to
be made to the central location, the digital communicator maintains the call.
When the
call is answered by the central location, alarm information is transmitted to
the central
computer. As will be appreciated, during an alarm condition, a telephone call
is
established between the alarm system and the central location. Thus, long
distance
telephone charges may apply to the call made by the alarm system. Also, if the
call
made by the alarm system is carried out over a wireless network, airtime
charges may
apply.
Furthermore, regulations often require security systems to be tested on
a regular basis. In the case of the Hartley et al and Drysdale et al systems
described
above, this requires a telephone connection to be established between the
alarm
systems and the central locations. If long distance charges apply or if
wireless
communication network airtime charges apply, costs are added to the ownership
of the
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alarm systems.
It is therefore an object of the present invention to obviate or mitigate
the above-identified disadvantages.
DISCLOSURE OF THE INVENTION
According to one aspect of the present invention there is provided a
monitoring station to monitor the status of at least one remote site over a
public
switched telephone network (PST1~, said monitoring station comprising:
a plurality of call receiving interfaces to receive calls from said at least
one remote site over said PSTN and accompanying caller identification data,
each call
receiving interface having a telephone number corresponding to specific
information to
be conveyed from said at least one remote site to said monitoring station; and
a processor in communication with said call receiving interfaces, said
processor receiving call receiving interface identification data and caller
identification
data in response to calls received by said call receiving interfaces to allow
said
processor to receive specific information from said at least one remote site
and its
identity without requiring said call receiving interfaces to answer the calls.
Preferably, the caller identification data is caller line identification (CLI)
data generated by the PSTN. In one embodiment, the at least one remote site
includes
a plurality of sensors, each of the sensors being assigned a unique number. In
this
case, selected call receiving interfaces have telephone numbers incorporating
the
numbers of particular sensors so that calls received by each selected call
receiving
interface from the at least one remote site in response to sensor output,
identify the
sensor responsible for the calls. CLI data accompanying the calls identifies
the location
of the sensors.
In another embodiment, the at least one remote site includes at least one
meter for measuring a utility consumption and storing a meter reading. In this
case,
selected call receiving interfaces have telephone numbers with digits
representing digits
of the meter reading and digit values so that calls received by selected call
receiving
interfaces from the at least one remote site identify meter reading digits and
values.
CLI data accompanying the calls identifies the location of the at least one
meter.
Prefereably, the processor polls a database storing information
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concerning actions to be performed in response to calls received by the call
receiving
interfaces. In one form, the processor is a computer. The monitoring station
further
includes a display coupled to the computer for displaying CLI data received
from the
call receiving interfaces as well as information read from the database. It is
also
preferred that the monitoring station further includes a printer coupled to
the computer
for printing the CLI data and information read from the database in response
to calls
received from the call receiving interfaces.
According to another aspect of the present invention there is provided a
system for communicating information and caller identification between
entities over a
IO public switched telephone network (PS'I'I~ comprising:
at least one remote site including a device whose status is to be
monitored, said remote site being coupled to said PSTN and being operable to
make a
call when the device status is to be determined; and
a monitoring station including a plurality of call receiving interfaces
coupled to said PSTN and a processor coupled to said call receiving
interfaces, each
call receiving interface being assigned a dii~erent telephone number
corresponding to
information concerning the status of said device, each call receiving
interface
conveying caller identification data received from said PSTN and caii
receiving
interface identification data to said processor in response to a call received
from said
remote site over said PSTN to allow said processor to determine the status of
said
device and its location without requiring said call to be answered.
According to still yet another aspect of the present invention there is
provided a method for monitoring the status of a device at a remote location
over a
public switched telephone network (PSTN) comprising the steps of:
determining the status of said device and using the status to generate a
telephone number;
dialing said telephone number to make a call over said PSTN, said
telephone number corresponding to a specific call receiving interface of a
monitoring
station;
dropping the call after a sufficient number of ringing signals have been
received by said specific call receiving interface to ensure deliver of caller
identification
data to said call receiving interface by said PSTN; and
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processing the caller identification data and call receiving interface
identification data to determine the location and status of said device
without requiring
the call to be answered.
According to still yet another aspect of the present invention there is
provided a method for conveying the status of a device at a remote location
over an
Internet connection to a monitoring station comprising the steps of
determining the status of said device at said remote location and using
the status to generate an electronic mail (e-mail) address leader;
generating an e-mail address by appending said leader to the site
address assigned to said monitoring station;
dispatching an e-mail message to said monitoring station including said
e-mail address and a return address assigned to said remote location; and
processing the e-mail message by examining the e-mail address leader
to determine the status of said device and the return address to determine the
location
of said device.
The present invention provides advantages in that information can be
sent and received between entities over a PSTN with incurring long distance or
airtime charges. In addition, information can be transmitted over an Internet
connection in an manner which limits the amount of power and memory required
to
process the information.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the present invention will now be described more fixlly
with reference to the accompanying drawings in which:
Figure 1 is a schematic block diagram of a security system in
accordance with the present invention;
Figure 2 is another schematic block diagram of the security system of
Figure 1; and
Figure 3 is a schematic block diagram of an alternative embodiment of a
security system in accordance with the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
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The present invention relates to communications between two
independent systems over a public switched telephone network (PSTN).
Identification
information accompanying a call made by one of the independent systems to the
other
is used by the independent system receiving the call so that appropriate
action can be
taken and without requiring the called independent system to answer the call.
As a
result, long-distance and/or airtime charges are avoided. Although the present
invention is of general application, preferred embodiments of the present
invention in
relation to security systems will now be described for ease of understanding.
Turning now to Figures 1 and 2, a security system in accordance with
the present invention is shown and is generally indicated to by reference
numeral 10.
Security system 10 is designed to monitor one or more locations or premises 11
(hereinafter referred to as "locations") and generate calls to a remote
monitoring
station 13 in response to alarm conditions. As can be seen in Figure 1,
security system
in this embodiment includes a plurality of alarm panels 14, each of which is
associated
with a particular location 11 to be monitored. A plurality of sensors 12 are
connected
to each of the alarm panels 14. The sensors 12 connected to each alarm panel
14
monitor the associated location 1 l and provide information to the alarm panel
concerning the status of the monitored location. Each sensor 12 is assigned a
unique
sensor number XY that is stored in memory (not shown) within the alarm panel
14.
The alarm panel 14 is connected to a public switched telephone
network (PSTN) 20 via a telephone channel 18 and includes a modem (not shown)
to
dial a telephone number in response to an alarm condition, a ring tone
detector 16 such
as that manufactured by Teltone under part No. M980 or M981 to detect ring
back
tones generated by the PSTN 20 and a call receiving interface 26 to receive
calls
received from the PSTN 20 (see Figure 2). The alarm panel 14 also stores a
partial
telephone number 123 456 78xy that is completed using sensor numbers XY to
generate calls to the central monitoring station 13 in response to an alarm
condition as
will be described.
PSTN 20 includes a computer 22, which forwards caller line
identification (CLI) data to called parties thereby to identify the calling
parties. PSTN
20 may be a landline communication network, a wireless or cellular
communication
network or a combination of landline and wireless communication networks.
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The central monitoring station 13 includes a plurality of call receiving
interfaces 26, each of which is connected to the PSTN ZO via a telephone
channel 24.
Each call receiving interface 26 has a unique telephone number that is
associated with a
particular sensor number. The call receiving interfaces 26 are connected to a
computer
30 via communication channels 28. Computer 30 is responsive to operator input
38
and communicates with a customer database 40. Computer 30 also provides output
to
a display 42 and to a printer 44.
As can be seen in Figure 2, computer 30 also includes a ring tone
detector 16 and communicates with a plurality of call dialing interfaces 46
over
communication channels 48. Each call dialing interface 46 has an associated
telephone
number whose last two digits represent a dii~erent action code as will be
described.
The security system 10 is designed to notify the central monitoring
station 13 when alarm conditions are detected by the sensors 12. CLI data
accompanying the calls is conveyed to the computer 30 at the central
monitoring
station via the PSTN 20 to enable appropriate action to be taken without
requiring the
calls to be answered. Specifics of the security system operation will now be
described
further.
During operation, when a sensor 12 detects an alarm condition, an
alarm signal is sent to the associated alarm panel 14. In response to the
sensor alarm
signal, the alarm panel 14 determines the sensor number XY and appends the
sensor
number to the partial telephone number stored therein to complete the
telephone
number 123 456 78XY. The completed telephone number corresponds to the
telephone number of the call receiving interface 26 that is associated with
the triggered
sensor 12. At this time, the alarm panel 14 causes its modem to dial the
completed
telephone number 123 456 78XY thereby to generate a call.
PSTN 20 upon receiving the call from the alarm panel 14, directs the
call to the appropriate call receiving interface 26 and notifies the alarm
panel 14 by
returning ring back tones corresponding to ringing signals received by the
call
receiving interface 26. The PSTN 20 also conveys CLI data to the call
receiving
interface 26 after the first ringing signal is received by the call receiving
interface 26.
The CLI data includes the telephone number assigned to the location 11 at
which the
alarm panel 14 is located.
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The ring tone detector 16 in the alarm panel 14 monitors the telephone
channel 18 to detect the ring back tones generated by the PSTN 20. The alarm
panel
14 counts the number of ring back tones and terminates the call after a
sufficient
number of ring back tones have been received to ensure delivery of the CLI
data to the
call receiving interface 26. In this manner, the call receiving interface 26
receives CLI
data identifying the location of the tripped sensor 12 without requiring a
telephone
connection between the alarm panel 14 and the call receiving interface 26 to
be
established.
When the call receiving interface 26 receives the call and accompanying
CLI data from the PSTN 20, the call receiving interface 26 extracts and
interprets the
CLI data in a conventional fashion. The call receiving interface 26 then
generates an
electronic data signal corresponding to the CLI data and combines this
electronic data
with data identifying itself for forwarding to the computer 30 at the central
monitoring
station I3 for further processing. Thus, computer 30 is informed of the
location of the
tripped sensor 12 by virtue of the CLI data and the identity of the tripped
sensor by
virtue of the call receiving interface identification data. If desired, the
call receiving
interface 26 can include a display (not shown) to display CLI data immediately
upon
receipt.
After the call receiving interface 26 has combined the CLI data and its
identification data, the data is immediately conveyed to the computer 30.
Computer 30
processes the data to identify the location where the alarm condition exists
and the
nature of the alarm condition. This information is then presented on display
42 and
printed via printer 44. Computer 30 also polls the customer database 40 to
determine
the steps to be carried out in response to the alarm condition. These
instructions can
also be presented on display 42 and printed via printer 44.
Sabotage of the computer 30 at the central monitoring station 13 can
occur by flooding of the call receiving interfaces 26 with false calls. Since
the call
receiving interfaces 26 pass the CLI data to the computer 30, which compares
the CLI
data with the customer database 40, calls from external telephone sources are
detected.
In this case, an attempt to sabotage can be assumed and the external telephone
source
can be identified by its CLI data.
The computer 30 at the central monitoring station 13 can also transmit
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codes to the alarm panels 14 via the PSTN 20. The codes represent instructions
for
the alarm panels to perform desired actions. In this embodiment, the codes are
represented by two digits and include a "reset" sensor code and a "re-dial"
telephone
number code.
When a code is to be transmitted to an alarm panel 14, the computer 30
selects a call dialing interface 46 having a telephone number whose last two
digits
represent the desired code to be transmitted. The computer 30 then instructs
the call
dialing interface 46 to dial the telephone number of the location 11 at which
the alarm
panel 14 is located. In response, the call dialing interface 46 dials the
telephone
number. The PSTN 20 in turn directs the call to the call receiving interface
26 at the
location 11 together with CLI data identifying the call dialing interface 46
in the same
manner described previously. The call receiving interface 26 in turn extracts
and
interprets the last two digits of the CLI data. The last two digits of the CLI
data,
which represent the code, cause the alarm panel 14 to take the necessary
action
corresponding to the code, such as reset a tripped sensor or re-dial the
telephone
number of the call receiving interface 26.
In order to set up the security system 10, during installation, the alarm
panels 14 complete installation communication routines so that CLI data
generated by
the PSTN 20 is matched properly to the individual sensors 12. During
installation, the
customer database 40 is also completed so that appropriate steps are taken in
response
to alarm conditions.
Since the CLI data is generated by the PSTN 20, the information it
provides concerning the location of the tripped sensors is accurate and is not
subject to
alarm panel installation errors or purposeful corruption at the alarm panel
locations.
Also, since CLI data is used to identify the alarm condition location,
problems
associated with transmission of data signals such as noise, cross-talk,
sabotage or other
errors are mitigated.
As will be appreciated, with a PSTN 20, the alarm panels 14 may be
moved by the owner without great concern since the CLI data generated by the
PSTN
20 identifies the current locations of the alarm panels 14.
If desired, the ring tone detectors 16 can be conditioned to detect "line
busy" and "reorder" tones generated by the PSTN 20 in response to calls, which
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cannot be completed. In this case, the alarm panels 14 interpret these tones
as error
indicators and maintain error logs.
Also, if desired, the alarm panels 14 may also be programmed with the
telephone number of a call receiving interface 26 designed to answer calls
from the
alarm panels 14 and maintain an on-line connection to the computer 30. In tlvs
manner, the computer 30 can test the alarm panels 14, remotely program the
alarm
panels 14 and/or monitor the locations 11. In this case, the alarm panels 14
respond to
a code received from a call dialing interface 46, which causes the alarm
panels 14 to
dial the telephone number of the call receiving interface 26.
Turning now to Figure 3, another embodiment of a security system in
accordance with the present invention is shown and is generally indicated to
by
reference numeral 100. The security system 100 of this embodiment is very
similar to
that of the previous embodiment. However, in this embodiment, meters 11 S and
117
for monitoring utility consumptions and storing meter readings are also
connected to
the alarm panel 14.
The meters 115 and 117 can be read either in response to a code
received from a call dialing interface 46 or at predetermined intervals. When
a meter is
to be read, the associated alarm panel 14 reads the meter and saves the read
meter data
in memory therein. The read meter data can be the current meter value, the
peak
demand, the difference between the current meter value and the last read meter
value
etc. If desired, the alarm panel may compress the read meter data using any
conventional compression algorithm.
Similar to the previous embodiment, some of the call receiving
interfaces 26 have unique telephone numbers associated with particular sensor
numbers. However, in this case, some of the call receiving interfaces 26 have
unique
telephone numbers associated with a particular digit of a meter value.
Thus, when an alarm panel 14 reads a meter either in response to a
received code or at a predetermined interval, the alarm panel 14 completes a
list of
telephone numbers using the read meter data. The second last digit of each
telephone
number identifies a specific digit of the read meter data while the last digit
of the
telephone number identifies the actual value of the digit. Once the list of
telephone
numbers is completed, the alarm panel 14 generates a series of calls to call
receiving
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interfaces 26 and drops each call after the PSTN 20 has forwarded the CLI
data. As a
result, the identities of the call receiving interfaces 26 receiving the calls
and the
accompanying CLI data identify the meter and its read meter data. Thus, all of
this
information can be transmitted by an alarm panel 14 to the central monitoring
station
13 without requiring the calls to be answered. The call receiving interfaces
26 extract
the read meter data and convey this data with the CLI data to the computer 30
for
processing.
Although the call receiving interfaces 26 and computer 30 are shown
separately, those of skill in the art will appreciate that they may be
combined into a
single unit. Also, as will be appreciated, the CLI data provided by the PSTN
20 may
vary. The exact information provided by the CLI data is not significant since
the
present system uses the information simply to identify the calling party.
In yet another embodiment, electronic mail (e-mail) may be used by the
alarm panels 14 and computer 30 to transmit messages over an Internet
connection.
As is well known to those of skill in the art, electronic equipment equipped
with e-mail
capabilities are assigned site addresses of the form @xxxx.yy(y). Any e-mail
message
having a site address corresponding to that assigned to electronic equipment
will be
delivered to the electronic equipment regardless of the characters in front of
the site
address. It is up to the electronic equipment to decode the characters in
front of the
site address.
Accordingly, in the security system according to the present invention,
the alarm panels 14 can be configured to send e-mail messages to the computer
30 to
notify the computer 30 of an alarm condition or a read meter value. In this
case, the
characters in front of the site address of the computer 30 identify the
tripped sensor or
read meter value while the return e-mail address identifies the location 11.
Since only
the e-mail address fields are used to convey information to the computer 30,
processing power and memory requirements are significantly reduced as compared
to
systems which use message fields to convey information. Of course, the
computer 30
can also use e-mail messages to convey action codes to the alarm panels 14.
Although the present invention has been described with specific
reference to security systems, those of skill in the art will appreciate that
the present
invention may be used in virtually any environment where information from a
remote
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site needs to be sent to a monitoring location. For example, the present
invention may
be incorporated into vending machines to allow inventory and sales information
to be
conveyed to a monitoring station or incorporated into environmental control
systems
to allow environmental condition information to be conveyed to a monitoring
station.
The present invention may also be used to transmit GPS data or pre-recorded
message
data to monitoring stations.
Although preferred embodiments of the present invention have been
described, those of skill in the art will appreciate that variations and
modifications may
be made without departing from the spirit and scope thereof as defined by the
appended claims.
