CA1173575A - Communication system - Google Patents

Abstract

ABSTRACT

A voice frequency communication system is provided in which communication is established between premises and at least one service facility. A
computer, connected to a telephone exchange which is connected to the premises, can effect connection to the at least one required service facility. A
terminal located at the premises is used, in conjunction with the computer, to establish a voice frequency communication channel between the premises and a required service facility, on the basis of a predetermined priority of connections, and to display information on a visual display unit located at the premises. At all times, the system indicates (at least on the visual display unit) the presence of an incoming telephone call. Typical service facilities include police, fire and medical alerting facilities.

Description

TITLE:

"COMMUNICATION SYSTEM"

TECHNICAL FIELD
This invention concerns communication systems. More 5 particularly it concerns communication systems operating at "voice frequency" frequencies (VF frequencies), which utilise voice channels, such as telephone lines and radio channels that are reserved for voice communication. Within the term "telephone lines" are 10 included line concentrated telephone systems and telephone systems using time division multiplex digitized transmission.
The invention permits greater utilisation of telephone lines while ensuring the inviolate nature of 15 the telephone service in systems that are currently reserved for one service use absolutely.
BACKGROUND ART
There is a growing recognition by socially aware people of the need to be able to provide information 20 about a myriad of events or circumstances. Among these events are (a) the fact that a telephone call was made to a telephone subscriber when the subscriber was away from the telephone, (b) the fact that an intruder has entered premises, and (c) that urgent medical attention 25 is required. (These examples are not intended to be regarded as an exhaustive list.) Devices which provide information about a single event have been developed for most, if not all, of these requirements. However, such devices, when they use a telephone line to convey the 30 information, require the installation of additional telephone lines (or voice channels) and additional equipment to that already installed. They are generally expensive, limited in their function, energy consuming and sometimes unavailable due to lack of the requisite :~ 1735~

communication facility or the impracticality of providing necessary additional telephone lines or channels.
To illustrate this point, consider the systems which 5 enable live telephone answering services to operate.
Such systems require a second telephone line to each subscriber who wishes to use the service. If the relevant telephone exchange has already used most of the lines available to subscribers, there may be 10 insufficient lines available to subscribers who require the answering service in the locality serviced by the exchange. In such a situation, either the answering service will be available for only a limited number of telephone subscribers, or the small number of 15 subscribers that could be connected to the service may mean that the service has insufficient clients for a commercially viable operation, so that nobody in a particular district can have access to the service.
In an attempt to overcome this problem, E.H.B.
20 Bartelink has proposed a remote supervisory system in which a plurality of sensors are adapted to provide an alarm signal on the occurrence of, for example, a fire or an intruder. When the alarm is generated, auxiliary equipment in the premises where the sensors are located, 25 which monitors the sensors, causes the normal telephone service to the premises to be disconnected for a short time. During that short "off hook" period, the auxiliary equipment causes a signal to be transmitted along the telephone line to the premises, and this signal is acted 30 upon in the telephone company's central office or in the telephone exchange, where a computer initiates appropriate signal transmission to the agency to be alerted ~for example, the fire brigade or the police station).
A disadvantage with Bartelink's system, which is 5 sufficient to prevent its adoption in many countries (including Australia) where, for policy reasons, the telephone service must at all times have priority, is that during the transmission of the alarm signal, the telephone line is "busied ou*" - that is, it is not 10 available for telephone calls to and from the premises containing the alarm sensors.
DISCLOSURE OF THE INVENTIO~
One of the objectives of the present invention is to provide a communication system which can be used in most 15 locations, without additional communication lines being provided, which is economic in its provision and running, which is relatively simple, and which leaves the telephone line intact at all times.
This objective is achieved by providing an 20 improvement on the Bartelink system which has been discussed above. The improvement consists of a) providing a visual display unit (VDU) in the premises in which the alarm sensors have been installed, with each monitored function (including an incoming telephone call) having a respective display on the VDU; and b) at the telephone exchange or its equivalent, the telephone line from the premises is connected by jumpers to a computer which reacts to alarm signals (and other signals) from the sensors or other equipment installed in the premises, but which permits, at all times, a telephone call to be transmitted to the premises.
In this arrangement, both alarm or other signals and 35 telephone conversations will be transmittable, in the voice frequency band, simultaneously, using the one voice frequency channel. Usually the presence of an 3 :~3575 alarm or other function signal will be noted during a telephone call by the presence of a tone - perhaps a modulated tone - additional to the conversation.
It is known that superimposition of signals on 5 existing lines has been used, or proposed, previously.
For example, ripple control of the operation of street lights, traffic lights, off-peak water heaters, and the like, using audio-frequency signals superimposed on the power cables to the devices being controlled, is a 10 long-established procedure. More recently, the ~ritish Post Office has proposed an alarm system in which out-of-band alarm signals are transmitted over a telephone line to receivers using a modulated carrier wave having a frequency which is outside the audio-frequency range.
15 Those skilled in this art, however, will recognise the distinction between in-band multiple slgnal transmission of the present invention and the out-of-band superimposed signal concepts of ripple control systems and the aforementioned Post Office signalling systems.
According to the present invention, a voice frequency communication system between premises and at least one service facility comprises:
a) a voice frequency channel between a telephone exchange and the premises;
b) a computer located at or connected to the exchange, to which computer a plurality of voice channels at the exchange are connected; said computer being adapted to be connected to at least one service facility;
c) at least one sensor located in or adjacent to the premises; and d) a terminal located at the premises and connected to the voice channel at the premises and also to the or each said sensor;
said system being characterised in that:

~ ~73~5 e) a visual display unit is also located in said premises and is adapted to have a display thereon when a telephone call is made to the premises and whenever a signal is generated by the sensor or sensors;
f) the computer is adapted to establish communication between the terminal and said, one or a plurality of said facilities in response to signals from the or each sensor;
and g) the connection between the voice frequency channel to the premises and the computer is by jumpers.
In most built-up areas, the voice frequency channel 15 will be the two-wire telephone line which connects the premises to the telephone exchange, and the plurality of voice channels at the exchange will be the other telephone lines, or some of the other telephone lines, entering the exchange (including, of course, the 20 telephone line from the premises).
It should be noted that the word "premises" in this specification has a connotation which is wider than simply a building. (In fact, in this specification, "premises" includes dwellings of any kind, schools, 25 factories, work-rooms, shops, boarding houses, tents and other buildings or structures (whether temporary or permanent); it also includes any vessel lying in any river, harbour or other water; this list is not exhaustive.) This is important to note, for in remote areas, where communication between camps, boats, drilling rigs and the like is often by single side band radio transmission in radio channels in which the voice channel band of from 200 to 3,400 Hz is reserved for a 35 "telephone" service use, the voice channel of the present invention will be such a radio channel.

,, ~ ~73575 In the "built up" environment, the service facility or one of the service facilities will usually be a live telephone answering service, which is actuated by a signal from the terminal, establishéd when an incoming 5 telephone call is received in the premises and either (a) the incoming call is not answered within a predetermined time or (b) the terminal has been manually set to indicate the absense of the occupier of the premises.
The terminal of the present invention may also include connections to sound-producing or visual alarm indicators.
These and other features of the present invention will be more clearly appreciated from the following 15 description of embodiments of the present invention, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a block diagram of a simple system, established in accordance with the present invention.
Figure 2 is a block diagram of a system established in accordance with the present invention, which utilises additional service facilities and display units to those of the embodiment illustrated in Figure 1.
Figure 3 is a circuit diagram of a system which uses 25 impulse signalling which may be used in establishing a system of Figures 1 and 2.
DESCRIPTION OF ILL~STRATED EMBODIMENTS
_ Referring first to Figure 1, there is shown, schematically, premises 10 connected to a telephone 30 exchange 11 by a two-wire telephone line 12. In the absence of the system of the present invention, the telephone line 12 would be connected directly to a telephone 13 in the premises 10. In the arrangement shown in Figure 1, however, the telephone line 12 is 35 connected, in the premises, to a computer terminal 14 which is also connected to telephone 13. When the occupier of the premises is within the premises, the terminal 14 will usually be set to connect the telephone ~ ;

~ ~73~75 13 directly to telephone line 12, thus enabling incoming calls to be received normally. If the occupier of the premises is absent, the terminal 1~ will be set to enable incoming telephone calls to be directed to a 5 telephone answering service 19 (through an arrangement to be described below). As indicated earlier in this specification, terminal 14 will normally be set to direct incoming telephone calls to the telephone answering service if the telephone 13 is not answered 10 within a pre-determined time period. This will ensure that an inadvertent omission to set terminal 14 to the "answering service" mode on leaving the premises will not result in the incoming call being an abortive attempt at communication.
Also connected to the terminal 14 is a visual display unit 15. This unit is adapted to display an indication that an incoming telephone call is being made, even when the system is transmitting an alarm signal or when the incoming call has been directed to 20 the answering service facility 19. In a more extensive system, the visual display unit, which may also function as the family television set, will usually be adapted to display a wide range of information.
Another feature included in the system illustrated 25 in Figure 1 is a heat and/or smoke sensing device 16.
This is connected to the terminal 14 and is arranged to sound an audible alarm 17 and provide a signal to the fire brigade's monitoring service 101. Such an arrangement will be connected to terminal 14 in such a 30 manner that if sensor 16 responds to heat and/or smoke, the connection of an alarm signal to monitor 101 will take place while normal telephone calls are being made using line 12, and during any recordal of calls by the telephone answering service 19.
At the exchange 11, the normal path of line 12 is interrupted and the line is connected via jumpers 104 and 105 to a computer 18. Computer 18 may be located within the exchange or in a separate location. In the ~ ~73575 illustrated embodiment, only line 12 is shown connected to computer 18 but in practice, a plurality of lines will be connected to computer 18.
The computer 18 is designed and operated to allow 5 normal telephone communication through line 12 to premises 10 but to be responsive to signals from terminal 14 which indicate that (a) there has been actuation of the heat and/or smoke sensor 16, or ~b) the unoccupied premises require incoming telephone calls to 10 be directed to the answering service 19. In the presence of a signal from the terminal 14 indicating actuation of sensor 16, a connection is made to the fire brigade monitoring service 101, and details (usually by code) are provided to the fire brigade of the location-of the 15 premises 10 where a fire must be presumed to have broken out. The presence of the "unoccupied premises" signal from terminal 14, either by manual selection of that mode for terminal 14 or the failure to answer an incoming call to telephone 13, will cause line 12 to be 20 redirected to the answering service 19. As indicated above, the signal from the terminal 14 in response to actuation of sensor 16 will have priority.
The system illustrated in Figure 1 is a relatively simple system, illustrating the present inventive 25 concept. Those skilled in the art will appreciate that this system can readily be adapted to include a large number of monitoring and information providing facilities. Among these are:
a) Security monitoring (detecting the presence of an intruder and providing a signal to the police station with silent and/or audible alarm and~or television camera or phGtographic monitoring);
b) calling required tradesman (plumber, electrician, motor mechanic, washing machine serviceman, refrigerator serviceman, and the like), with remote security entry control of the tradesman if required (remote security entry control could utilise a magnetically codable card, which is , .
,~

~ 1735~5 coded by the computer when it is used, after identification, to enter the premises and is decoded again when the service call has been completed and the tradesman leaves the premises);
c) health emergency call (to nurse, in the case of patient requiring occasional emergency treatment of known type, using a monitor or signalling device carried by the patient, or to doctor or ambulance service);
d) taxi re~uired;
e) visitor monitoring with message recording;
f) "appliance on" monitors;
g) provision of a display of time, latest weather data, sports results, and the like on a~visual display unit; and h) shopping list transmission to a selected store.
This list is not an exhaustive list.
Figure 2 illustrates (schematically) another example of the system of the present invention in use.
In Figure 2, the premises 20 are provided with a terminal 24 connected to telephone line 22. The terminal 24 has a plurality of input signals derived from monitors 26A, 26B and 26C, which may be, for example, a heat/smoke sensor, an "intruder present" indicator and 25 sensors adapted to signal that "the oven is switched on"
or "the power to the freezer is disconnected". Terminal 24 also has an intercom connected from the front door of the premises, the connection being shown as intercom input 206. Terminal 24 is also provided with a visual 30 display unit 25, a voice recorder 25A (for use with intercom service 206), a telephone 23, a plurality of specific services signal transmission selectors 207 (for example, taxi-call, clock or other in~ormation required on visual display unit 24, call to doctor or tradesman, 35 and the like), a visual and audible alarm 27, a loudspeaker system 27A.

~. ~735~5 For use with such an arrangement in premises 20, the computer 28 at, or connected to, telephone exchange 21, which is connected to telephone line 22 by jumpers 204 and 205, is programmed to direct, on a priority of needs 5 basis, original signals at voice frequency from terminal 24 to telephone answering service 29, to clock, weather, sport or other information transmitters 29A, 29B, 29C ..., and to fire brigade, police station, nurse, and the like at 201, 202, 203, ....
A TELEX service 209 may also be included in the system.
The system of Figure 2 is also provided with an external visual display unit 208 which is under 24 hour surveillance. The computer 28 is programmed to ensure 15 that a visual and audible signal is provided by visual display unit 208 in the event that the line 22 is disconnected (for example, by accidental fracture or by sabotage of the line 22). Such a signal will then be treated as a general alarm and all appropriate emergency 20 services will be alerted. Society is prepared to tolerate a reasonable level of false alarms. Preferably, with such a system, the computer 28 will also be programmed to analyse the occurrence of general alarms, and to advise (by an appropriate signal) the likelihood 25 of a general failure in a particular region when a predetermined plurality of general alarms occurs simultaneously.
The operation of the system of Figure 2 should be clear from the description, above, of the operation of 30 the system of Figure 1. It should be noted, however, that because the telephone service to the premises is inviolate, it will be usual practice for the visual display unit 25 to be adapted to display, at all times, the occurrence of an incoming telephone call. Such a 35 display might be the flashing of a message such as "telephone ringing" on the screen of unit 25, which is superimposed on the information that is then being displayed on the screen. The user of the system, in the .~

~. 1 7 3 5 7 5 premises 20, then has the option to decide (in the same way as any person in a house or office equipped with a telephone has this option) to answer the telephone 23, or not to answer the telephone. By answering the 5 telephone, the user of the system effectively determines that top priority is to be given to the telephone call, and on lifting the receiver of the telephone 23, the previously displayed information on the screen of the visual display unit 25 is automatically removed.
By way of example, one form of circuit for adapting an existing te?ephone line to operation in accordance with the present invention is shown in Figure 3. This circuit uses two optically coupled isolators 33 and 34 located in one of the wires constituting the telephone 15 line in, respectively, premises 30 and telephone exchange 31. This circuit, which uses readily available components, ~. 173575 may be used with a primitive form of information signalling, known as "impulse signalling~, which uses a mechanical make-break contact.
As shown in Figure 3, a DC voltage E is established across the pair of wires, so that a current flows through the wires. Resistors Rl and R2 control the level of the constant DC current through the wires. In a typical telephone system, the constant current will be of the order of 0.5 milliamp, which is sufficient to keep light emitting diodes Dl of the optically coupled isolators 33 and 34 in their light emitting mode, but insufficient to ring the bell of a telephone. Usually, a current in excess of 5 milliamps, and often about 20 to 30 milliamps is required to operate a telephone line.
Such a high level of current will not affect the operation of the optically coupled isolators, but if a current of greater than about 200 milliamps is likely on the lines, current protectors should be fitted to the optically coupled isolators.
With the light emitting diodes continually operating, an indication is provided at both the premises 30 and the exchange 31 that the telephone line is operating satisfactorily. It is thus unnecessary to interrupt the operation of the system to test that it is operational.
Each light emitting diode is located alongside a photo-sensitive diode Pl, which conducts when light is incident upon it. Failure to conduct can be readily monitored. This feature is used in the system illustrated in Figure 3, where the presence of any alarm or "function required" signal opens switch Sl. The current through diodes Dl is now removed and diodes Dl no longer emit light. Photo-sensitive diodes Pl then no longer conduct and an ~ ~735~5 "alert" signal is generated at the computer(not shown in Figure 3). An "alert" indication may also be provided in the premises 30 and in exchange 31. The computer then sends an interrogation signal to the terminal (not shown in Figure 3) in the premises 30, which indicates the alarm or service required. The computer then activates the auto-dial make-break system 35, to provide the connection to the appropriate service facility. The auto-dial system 35 can also be used to provide the terminal at the premises 30 with an acknowledgement that an alarm (or other) signal has been received from the premises by the required facility.
Optically coupled isolators suitable for use in a circuit of the type shown in Figure 3 are already available on the market. For example, they are produced by Fairchild Corporation, as catalogue component No. 4N33.
Note that for a telephone answering service, the arrangement shown in Figure 3 will not be used. Ring-detectors for such purpose, which are already well developed, standard components, will be located in the exchange 31 and selected as required.
Existing independent alert systems are normally provided with an automatic monitoring system, which tests each connection to the system at least once a day. While such a test is being carried out, the system itself will be inoperable.
A feature of the present invention is that it readily includes a continuous monitoring of the system and, as noted above, a malfunction signal can easily be established, thus ensuring that, apart from a breakdown (which is treated as an alert), the system is operable throughout the entire 24 hour period.

1 ~735~l5 INDUSTRI~L APPLICABILITY
It has been shown above that the present invention is well suited for use with the conventional two-wires telephone connection to "premises". The invention is also applicable to the other types of voice channel communication, particularly to systems using line concentrators, carrier signal communication systems and time division r.lultiplex digitization systems.
With line concentrators, a plurality of telephone connections ~for example, the individual flats in a block of flats) are connected to a telephone exchange by a single two-wire telephone line. A line concentrator joins the plurality of connections to the single telephone line and a concentratox operating in reverse, located at the input to the exchange, separates the connections into a plurality of exchange lines. With this system, each individual connection retains its own identity at the block of flats and at the telephone exchange.
Thus the present invention could be used in a single flat which is connected to the telephone exchange only through a line concentrator.
Carrier systems also use a single two-wire telephone line to form a connection from a plurality of telephones and an exchange. In such systems, each telephone connection is provided with an oscillator, producing a carrier signal, which is modulated by the audio-frequency message to be conveyed over the telephone system. As the oscillators in a given system all produce a carrier signal at a frequency that is different from all the other carrier signals, a number of carrier signals can be simultaneously transmitted, without interference between signals, over a single two-wire telephone line, provided that ~ ~73575 there is a filter system and decoding arrangement for the signals at the exchange. Again, each telephone connection retains its own identity at the "premises" and at the exchange, and sc the system of the present invention may be used.
Voice frequency communication systems which use time divi~ion multiplexing also transmit a plurality of messages ~imultaneously over a ~ingle two-wire telephone line. In these systems, the individual messages from a plurality of telephone connections are divided into a number of time segments, and the corresponding segments of the plurality of messages are converted into digital form and transmltted sequentially over a single line. The fractions of the voice signals that have been transmitted in this way are combined, in a decoder which is synchronised with the "codex" equipment which chops the message signals into the required time segments and converts the signals into digital form, to r~-assemble each cn,mplete message and then put it on to its respective telephone line at the exchange. Yet again, there is no loss of identity of the individual premises as messages are transmitted to the exch~nge, so again the present inventivn is applicable.
As already indicated earlier in this specification! the present invention may also be used when te~ephone communication is effected by radio transmission, at frequencies reserved for telephone 3~ communication.

1 ~735~5 Finally, it is noted again that in all systems that include the present invention, there-are means to ensure that, at all times, the presence of an incoming telephone call is indicated at the premises. Thus, 5 whilst the telephone line is shared by a number of facilities, the actual telephone service remains inviolate. This is an important feature where local legislation, or government or company policy, requires an inviolate telephone service. The telephone service is 10 not interrupted; what is achieved with the present invention is an increased usage of the telephone line with (a) economical provision of a plurality of additional alert or service facilities for premises equipped with a telephone, and (b) line monitoring 15 provisions which are superior to existing line monitoring systems.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A voice frequency communication system between premises and at least one service facility comprising:
a) a voice frequency channel between a telephone exchange and the premises;
b) a computer located at or connected to the exchange, to which computer a plurality of voice channels at the exchange are connected; said computer being adapted to be connected to at least one service facility;
c) at least one sensor located in or adjacent to the premises; and d) a terminal located at the premises and connected to the voice frequency channel at the premises and also to the or each said sensor;
said system being characterised in that e) a visual display unit is also located in said premises and is adapted to have a display thereon when a telephone call is made to the premises and whenever a signal is generated by the sensor or sensors;
f) the computer is adapted to establish communication between the terminal and said, one or a plurality of said service facilities in response to signals from the or each sensor; and g) the connection between the voice frequency channel to the premises and the computer is by jumpers.

2. A system as defined in claim 1, in which the voice frequency channel is a two-wire telephone line, and the voice channels at the exchange are selected from the telephone lines entering the exchange.

3. A system as defined in claim 2, in which the telephone line between the premises and the exchange includes a system selected from the group consisting of: a line concentrator system, a carrier signal system, a time division multiplex digitization system, and a radio-signal link.

4. A system as defined in claim 1, claim 2 or claim 3, in which a plurality of sensors are located at the premises and connected to the terminal, and in which a signal produced by at least one of the sensors is effective to cause the terminal to provide an indication in the premises of the operation of the respective sensor, without establishing communication with the or a service facility.

5. A system as defined in claim 1, claim 2 or claim 3, including alarm means connected to said computer for providing a visual and/or audible alarm signal if the voice frequency channel is dis-established.

6. A system as defined in claim 2, further characterised in that:
a) a voltage source is connected across the two-wire telephone line at the exchange and a resistance circuit including a switch is connected across the two-wire telephone line at the premises to establish, when the switch is closed, a low level current in the telephone line which is insufficient to ring a telephone bell;
b) an optically coupled isolator is included in one of the two wires of the telephone line at the exchange, the optical isolator being adapted to produce an output signal when the low level current is established in the telephone line;
c) the computer is responsive to the output of the optical isolator; and d) the switch is in response to a signal from the terminal opened, to thereby dis-establish the low level current.

7. A system as defined in claim 6, including a second optical isolator connected in one of the two wires of the telephone line at the premises, and adapted to produce an output signal at premises, when the low level current is established in the telephone line, to thereby provide an indication at the premises that the line is established between the premises and the exchange.

8. A system as defined in claim 7, in which each optical isolator comprises, in combination, a light-emitting diode connected in a wire of the telephone line and a photo-sensitive diode responsive to the output of the light emitting diode.

9. A system as defined in claim 2, claim 6 or claim 7, in which the service facilities are selected from the group consisting of an alerting facility for police, an alerting facility for the fire brigade and an alerting facility for medical services.

10. A system as defined in claim 2, claim 6 or claim 7, including a TELEX service.