WO1993010621A1 - Method and apparatus for adding voice communications to telephone alarm system - Google Patents

Abstract

The alarm panel module (30) distinguishes activation of the telephone system by the alarm panel (13) from routine activation by the subscriber's telephones, detects the alarm panel's termination of the telephone link and transfers the link to a voice communication control (38) which sends an identifier code to the monitoring station (20) indicating two-way voice communication capability, and uses DTMF tones from the emergency operator's set to switch between listen and speak functions of the speaker/microphones (32). The voice line receiver (34) detects the monitoring station (20) terminates the link to the subscriber and captures the link for a brief period to detect a signal indicating that the subscriber is equipped for two-way voice communication, and if so, transfers the link to the emergency operator's telephone communication set.

Description

METHOD AND APPARATUS FOR ADDING VOICE COMMUNICATIONS TO TELEPHONE ALARM SYSTEM Technical Field

This invention relates to the general field of alarm systems of the type which use public telephone lines to communicate alarm information from sensors in subscriber residences or other buildings to one or more central monitoring stations. It relates in particular to permitting two-way voice communication between the alarm monitoring station and the subscriber site.

Background Art This invention is related to automatic telephone alarm systems as generally exemplified by the system described in U.S. Patent 3,527,892 (Kok). As patent described therein, earlier residential telephone alarm systems existed which used commercial telephone lines to transmit alarm information to central monitoring stations. However, the systems prior to Kok apparently did not disconnect and seize the lines from the residential telephones following the activation of an alarm. Examples of such prior systems are described in U.S. Patent 2,827,515 (Zuber) , which is summarized in the Kok patent.

Because of certain advantages described in Kok, most contemporary telephone alarm systems do seize the telephone lines and disconnect the local telephones. If it did not, a local alarm would be unable to contact the central monitoring station if the residential telephone happened to be in use when the alarm was tripped. Also, once the alarm system had obtained access to the residential telephone line and contacted the central monitoring station, the alarm continued transmitting continually over the line until manually reset, preventing the telephone from being able to answer any incoming calls, and simultaneously tying up a line at the central monitoring station.

Consequently, Kok disclosed an improved system similar to that depicted in Figure 1. In this prior art system, designated generally as 10, an alarm system master control panel 12 is provided to receive alarm signals from a variety of alarm sensors 14, and to seize control of the telephone lines from the residential phone system 16. Thus, a variety of alarms, such as door and window break-in alarms, fire and smoke detectors, motion detectors, medical monitors, manually operated emergency signals, and other varieties of alarms may communicate with the master control panel 12 via wire, radio frequency, or other transmissions. When an alarm from any one of the sensors 14 is received by the master alarm control panel 12, the panel disconnects and seizes the telephone lines 18 from the phone system 16, even though a residential telephone may be in use at that time, and once having seized the telephone lines, prevents the residential telephones from regaining control until the alarm messages have been transmitted to the central monitoring station and acknowledged.

Specifically, having disconnected and seized the lines from the residential phones, the master control panel 12 has conventional telephone circuitry which waits to detect a dial tone, then activates an automatic dialer programmed to dial the number code of an appropriate central monitoring station receiver. The auto-dialer continues to dial receiver code until it is answered by the receiver 20 at the central monitoring station. After the receiver 20 has answered and established the two-way telephone link, a message generator in the alarm panel 12 generates a coded message which identifies the subscriber station, and may in some instances identify the particular type of alarm which was tripped or the type of event which caused it to be tripped. This coded message is transmitted through the telephone lines 18 and the central monitoring station receiver 20 to a computer 22, which compares the coded message to pre-entered identifiers, and thus identifies the subscriber station and any other information such as the nature of the alarm. Having identified the subscriber and alarm, the computer 22 may display relevant information on a CRT screen for an emergency control operator, such as the name and address of the subscriber station, nature of the alarm and any pre-programmed instructions as to the appropriate response or persons to contact. The emergency control operator may select automatic transmission of this information to the appropriate response facility, such as a police department, hospital, fire station, or other entity.

When the coded alarm message is received by the monitoring station computer 22 and verified by various protocols, the monitoring station sends a "kiss-off" signal to the message generator and terminates its connection. The control panel 12 then terminates the local connection and releases control over the lines in order to free the lines for other calls.

Although the above-disclosed prior art alarm system is widely used, it clearly would be advantageous in some instances to maintain two-way voice communication directly between the emergency operator at the central monitoring station and any occupants of the subscriber building who may be in jeopardy or in need of assurance or instructions. In many instances, such persons cannot come to the residential phones to initiate a telephone link or respond to an incoming call. For example, where the person is immobilized by an injury, trapped in an area aware from the telephones, or being held captive, he can neither initiate or respond to a normal telephone call. Moreover, it is often beneficial for the emergency control operator to be able to simply listen to the noises and communications inside the subscribers station in order to determine further information about the emergency, such as whether a burglary is in progress, or whether persons are incapacitated but conscious. Two-way voice communication is also helpful in preventing a false alarm from causing the police or fire department or other agency from responding to a perceived emergency.

However, although many alarm systems having two-way voice communication exist, it could be difficult to integrate such systems into a networkwith existing alarm systems without two-way voice communication, and allow both types of system to operate to the same central monitoring station. This difficulty arises because of the variety of alarm systems, differences in telephone systems, and differences in the various protocols used between certain alarm systems and their central monitoring stations. For example, some alarm systems which do offer two-way voice capability do so by allocating a block of identifier codes for subscribers who choose voice capability, but this requires changing the identifier code whenever a subscriber adds or drops the voice communication option.

Further, it would be desirable to be able to modify an existing alarm system for voice communication rather than replace it with an entirely new system, although the system described herein may also be installed as original equipment.

Consequently, an obj ctive of the present invention is to provide a method and apparatus for modifying existing telephone alarm systems to have two-way voice communication. It is a further objective that the method and apparatus be adaptable for virtually any type of existing alarm system and central monitoring station combination. It is also an objective that an alarm system so modified can operate with the same central monitoring station as alarm systems which are not so modified and provide alarm information only. It is a further objective that the central monitoring station be able to distinguish which subscribers have the two-way voice capability from those who do not. It is a further objective to provide communication in the subscriber residence through strategically placed microphones and speakers, rather than the residential telephones. It is a further object of the invention to give the central monitoring station emergency operator control over the two-way voice communication. It is a further objective that the apparatus to be able to distinguish actuation of the telephone system by the alarm panel from activation by the normal house telephones.

summary Disclosure of the Invention

A method and apparatus are disclosed for adding two-way voice communication to an alarm system of the type which use public telephone lines to communicate alarm information from sensors in a subscriber building to a central monitoring station. The apparatus includes an alarm panel add-on module adapted for connection to the central alarm panel of the subscriber building's alarm system, and a voice line receiver module adapted for connection to the central monitoring stations receiver. Speaker/microphones are placed in the subscriber building, and one or more emergency operator's telephone communication sets capable of two-way voice communication and of sending DTMF tones to the subscriber station to cause switching between listen and speak functions of the speaker/microphones, are added at the monitoring station. The apparatus and method further disclose, within the alarm panel add-on module, means for distinguishing activation of the telephone system by the alarm panel from routine activation by the subscriber' telephones, for detecting the alarm panel's termination of the telephone link and for transferring said link to a voice communication control, for sending an identifier code to the central monitoring station indicating that this subscriber has two-way voice communication capability, and for using DTMF tones to cause switching between listen and speak functions of said speaker/microphones. Within the voice line receiver is disclosed means for detecting termination of the telephone link to the subscriber building by the monitoring station receiver, and for transferring said link to the voice-line receiver before the subscriber alarm panel terminates the link, for detecting the presence or absence of a signal from the subscriber building indicating that the subscriber is equipped for two-way voice communication, and for transferring the link, upon detection of said signal, to the emergency operator's telephone communication set.

Brief Description of the Drawings

For the purpose of illustrating the invention, the drawings show a form which is presently preferred; it being understood, however, that this invention is not limitedto the precise arrangements and instrumentalities shown.

Figure 1 is a schematic of an exemplary prior art telephone alarm system as described above.

Figure 2 is a schematic of a telephone alarm system modified according to the present invention to provide two-way voice communication.

Figure 3 is a schematic of logic and control circuitry of the add-on board attached to the master alarm panel at the subscriber station, according to the present invention. Figure 4 is a schematic of the logic and control circuitry in the voice line receiver of the central monitoring station, according to the invention.

Best Mode for Carrying Out the Invention

Referring now to Figure 2, added to the basic prior art telephone alarm system 10 are features of the present invention which permit two-way voice communication. At the subscriber station, an alarm panel voice module 30 is provided as an add-on integrated circuit board to the master alarm control panel 12. The module 30 provides logic and control functions to distinguish between a telephone connection initiated by the alarm panel 12 and that which is initiated by the residential telephones 16, and having identified a connection as initiated by the alarm panel, preserves the telephone link following the alarm panel's termination. The module 30 sends an identifier code to the central monitoring station indicating that this subscriber has two-way voice communication capability. Module 30 thereafter carries out switching between the listen and speak functions of various speaker microphones 34, which are placed at strategic locations within the residence, under the control of the central monitoring station's emergency operator. These functions will be described in further detail hereafter.

At the central monitoring station a voice line receiver module 34 detects when the monitoring station receiver 20 terminates its telephone link following acknowledgement of the alarm message, and immediately switches the telephone link to the emergency control operator's telephone set 36 if the alarm originates from a subscriber having a voice module 30. The voice line receiver 34 also cooperates with the emergency operator's touch tone telephone 36 to let the emergency operator control the speaker/microphones 32 in the residence, as further described below.

Module 30 is schematically depicted in greater detail in Figure 3. Timing and logic are provided by a conventional integrated circuit chip 38 available from Microchip Corporation as a PIC16C54. The functions to which its timing and logic are applied will be apparent from the other elements depicted in Figure 3 and the description which follows. A characteristic of the prior art telephone alarms systems described above is that the master alarm panel 12 is installed between the residential phone system and the telephone lines, so that routine telephone usage passes through the alarm panel 12. The panel 12 thus has a switching section, shown schematically as a double- switch relay 13 on Figures 1 and 2. Relay 13 is normally in the position depicted in Figure 1, which connects the residential telephones to the telephone lines. When the panel 12 receives a signal from a tripped alarm sensor, it changes the relay 13 to disconnect the residential phones and seizes control to connect the auto-dialer and message generator to the lines.

The alarm panel voice module 30 must distinguish routine telephone activity from alarm initiated activity in order to not respond to routine operation or activate the speaker/microphones following routine operation.

Consequently, two current detectors are used; a first detector 42 to detect current in the line from the house phones 16 to the alarm panel 12, and a second current detector 44 to detect current in the line out of the alarm panel to the telephone lines 18. The output of the current detectors are supplied to integrated circuit chip

38, which applies an AND gate function to distinguish routine telephone activity from alarm activity. When both current detectors detect line current, the activity is routine telephone. When only detector 44 senses current, the activity is alarm related, since even if the house phone was being used when the alarm tripped, the relay 13 will disconnect the telephones. Although current detectors are preferred, two voltage change detectors could be used instead.

After identifying an alarm initiated telephone activity, the module 30 does nothing until the alarm panel has auto-dialed and linked with the monitoring station and has sent its coded information to the station computer. At this point, in the basic alarm system, once the station computer has confirmed the accuracy and integrity of the message code by whatever confirmation protocol it uses, the station receiver sends a "kiss-off" signal to the subscriber's alarm panel and terminates the connection at the station receiver 20. Upon receipt and identification of the "kiss-off" signal, the alarm panel 12 also terminates its link to the telephone lines and resets the relay 13 for routine telephone operation.

In the present invention, the alarm panel voice module 30 and the voice line receiver module 34 cooperate to capture the link before it is terminated and to transfer communications to the emergency operator phone 36 and speaker/microphones 32, under the emergency operator's control. In the alarm panel voice module 30, a drop in the main line current is sensed by current detector 44 when the alarm panel terminates its connection following the kiss-off signal. The current drop causes a switching means depicted as a double-switch relay 58 to move away from the normal position shown in Figure 3 and connect the telephone lines across transformer 56. Also in response to this current drop, the system timing and logic integrated circuit chip 38 delays for a brief interval (« 5 seconds) to allow the central monitoring station connection to transfer to the voice line module, and then sends pulses to a touch tone generator 54 which produces a DTMF tone or tone sequence used by the monitoring station's voice line receiver to identify a subscriber with voice capability.

Referring now to Figure 4, a current detector 46 is used to detect when the monitoring station receiver

20 terminates connection, as indicated by a current drop, and immediately switches the connection to the voice line receiver module 34, by switching means shown schematically as a double-switch relay 48. This transfer occurs after the subscriber station alarm model 30 has picked-up the link, as described above. The relay 48 now connects the telephone link, through transformer 50, to a touch tone detector 52 to detect a DTMF tone or tone sequence which indicates that the subscriber station initiating the alarm is also equipped for two-way voice communications. Thus, the DTMF tones across transformer

56 are carried through the lines to detector 52.

A logic and timing integrated circuit 60 in the receiver module 34 holds the relay 48 for a preset time interval («10 seconds) after the monitoring station receiver's termination, and if no DTMF tone is received, resets the original conditions. However, if detector 52 receives the proper DTMF signifying voice capability within the time interval, the logic and timing device 60 sends pulses to tone generator 62, which produce a DTMF tone or tone sequence to acknowledge the voice alarm module 30. The DTMF tone is carried across the telephone lines to the tone detector 53 in module 30. The logic and timing device 60 also sends pulses to a ringing circuit 63 on the emergency operator's phone set 36, to alert the operator that a voice-link has been established with the subscriber, and switches phone connect relay 65 to connect the operator's set to the lines.

A current detector 64 senses when the emergency operator picks up the receiver of set 36. Thereafter two-way voice communication is under control of the operator, who can change the speaker/microphones 32 between listen and speak functions by his touch-tone keypad and switching relay 66. Relay 66, as shown in Figure 3, connects the speaker/microphones 32 to either an input amplifier 68 or an output amplifier 74, depending on the switch position of relay 66. When the emergency operator first picks up the receiver of set 36, the relay 66 is in the LISTEN position as shown in Figure 3, with the microphones connected to input amplifier 68. The operator may listen to noises or communications in the subscriber building to determine the nature and progress of the situation and decide upon his response. No sounds made at the monitoring station will be heard at the subscriber site, so that burglars or intruders will not be aware that their conversation is being monitored.

If the emergency operator decides that he should speak over the lines to give warning or advice, or to ask for information, he may press a selected button on his touch tone keypad, such as the # key. This produces a DTMF tone which is detected by detector 53 and signalled to the logic device 38, which in response produces a switching pulse on line 72 to relay 66, reversing the switch position and connecting the speakers to output amp 74. Persons in the subscriber site may now hear the voice of the emergency operator. If the operator wants to switch back to the listen mode, he presses another key, such as the * key, which produces a different DTMF tone to detector 53. Detection of this tone is signalled to device 38, which in response sends a switching signal to relay 66 to reverse the switch position to the LISTEN mode.

If there is excessive and continuous noise at the subscriber site, such as a siren, screaming or fire noise, the switching DTMF tone, which is in the audible frequency range, would be difficult to distinguish. Consequently, timing device 30 sends a signal to mute control relay 70, which holds the relay closed for normal listening, but breaks the signal for a 50 micro-second gap at one second intervals, to open the relay as shown in Figure 3. This gap provides an insignificant interrupt to the human ear, but is sufficient to allow the detector 53 to detect the switching DTMF tone and cause the relay 66 to switch.

If the alarm panel voice module 30 holds its line connection after the line receiver panel terminates its connection, the subscriber line would appear as a "busy" signal to anyone trying to call it. To prevent this, the alarm panel timing is set to terminate its connection if there is no incoming activity on the line for more than 60 seconds. However, since the emergency operator may want to listen silently for more than that period, the voice line receiver timing device sends a signal pulse to the tone generator 62 every 45 seconds. This "keeper tone" is not heard over the microphones 32 while relay 66 is in the LISTEN position, but is detected by tone detector 53, which resets the termination timing sequence of timing device 38 and allows silent listening as long as the emergency operator is still on the line.

Industrial Applicability

This invention is expected to be used for alarm monitoring centers who wish to offer their subscribers the capability of two-way voice communication with the monitoring center. The subscriber add-on module allows participating subscribers to add the capability without replacing the existing alarms and alarm panel. The invention allows the monitoring station to identify alarms from subscribers with voice capability and to transfer the line connection to an emergency operator who can manage the situation by voice communications while freeing the alarm receiver to receive other alarms. The invention can be used on telephone alarms without regard to the particular message conformation protocols used within the alarm system.

The subscriber sites are most likely to be residences, convenience stores and other retail outlets, and smaller commercial buildings which do not have an internal security force.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, reference should be made to the appended claims, rather than to the foregoing specification, as indicating the scope of the invention.

Claims

1. Amethod for adding two-wayvoice communication to an alarm system of the type which use telephone lines to communicate alarm information from sensors in a subscriber building to a central monitoring station comprising the steps of: at the central monitoring station, detecting termination of the telephone link to the subscriber building by the monitoring station receiver, and transferring said link to a voice-line receiver means before the subscriber alarm panel terminates the link, then waiting for a preset brief period of time to detect the presence or absence of a signal from the subscriber building indicating that the subscriber is equipped for two-way voice communication; atthe subscriberbuilding, distinguishing actuation of the telephone system by the alarm panel from routine activation by the subscriber' telephones, and having identified a connection as initiated by the alarm panel, detecting the alarm panel's termination of the telephone link with the central monitoring station, transferring said link to a voice communication control means which sends an identifier code to the central monitoring station indicating that this subscriber has two-way voice communication capability; at the central monitoring station, detecting said identifier code as a signal indicating that the subscriber is equipped for two-way voice communication, then transferring the link to an emergency operator's telephone communication set capable of two-way voice communication.

2. An apparatus for adding two-way voice communication to an alarm system of the type which use public telephone lines to communicate alarm information from sensors in a subscriber building to a central monitoring station comprising: one or more speaker/microphones placed within the subscriber building; an emergency operator's telephone communication set associated with the central monitoring station and capable of two-way voice communication and of sending DTMF tones to the subscriber station to cause switching between listen and speak functions of the speaker/microphones under the control of an emergency operator; an alarm panel add-on module adapted for connection to the central alarm panel of the subscriber building's alarm system, said module including:

(a) means for distinguishing actuation of the telephone system by the alarm panel from routine activation by the subscriber' telephones, and having distinguished a connection as initiated by the alarm panel,

(b) means for detecting the alarm panel's termination of the telephone link with the central monitoring station and for transferring said link to a voice communication control means,

(c) said voice communication control means for sending an identifier code to the central monitoring station indicating that this subscriber has two-way voice communication capability; a line receiver module adapted for connection to the central monitoring station receiver, said module including:

(a) means for detecting termination of the telephone link by the monitoring station receiver, and for transferring said link to a voice-line receiver means before the subscriber alarm panel terminates the link,

(b) means for detecting the presence or absence of a signal from the subscriber building indicating that the subscriber is equipped for two- way voice communication,

(c) means for transferring the link, upon detection of said signal, to the emergency operator's telephone communication set.

3. An apparatus as in claim 2, further comprising: said emergency operator's telephone communication set having means for generating DTMF tones, and said alarm panel module including means for using DTMF tones to cause switching between listen and speak functions of said speaker/microphones.

4. An apparatus as in claim 3, in which the means for using DTMF tones to cause switching between listen and speak functions of said speaker/microphones further comprise means for periodically interrupting the listen function for an interval sufficient to permit detection of the tones without distorting the audible information received by the emergency operator.

5. An apparatus as in claim 2, further comprising said alarm panel module having means for detecting communications activity from the emergency operator communications set and timing means for terminating the link if no activity is detected within a preset interval, and said line receiver module having means for producing a keeper signal to the alarm panel module at an interval less than the preset interval.