MXPA99010603A - Switch-based line continuity verification method and system - Google Patents

Abstract

In a security and alarm service environment, a method and system for verifying the continuity of a telephone line (317) connected to a subscriber terminal unit (STU) (310) at a customer's premises. The STU (310) is connected by telephone line (317) to a network interface (315) which is connected to a line unit (320) by a twisted pair (325). Line unit (320) is located in remote terminal (330) which is connected to switch (335) by digital loop (340). Switch (335) is connected to scanner (345) by trunk group (350) and SMDI link (355). A low tone generator in STU (310) generates a low frequency tone that is transmitted to line unit (320). If telephone line (317) is cut, if STU (310) malfunctions, or if an alarm condition at the customer's premises is detected by STU (310), then the low tone is not received by line unit (320). Remote terminal (330) encodes a signaling bit that is transmitted over digital loop (340) to switch (335). The encoded signaling bit indicates whether or not the low tone was received by line unit (320). Switch (335) reads the encoded signaling bit and, if the encoded signaling bit indicates that the low tone was not received, sends a directory number to the scanner (345). The switch (335) connects the scanner (345) to the telephone line (317) so that the alarm service provider can query the STU (310) to determine the problem.

Description

METHOD AND SYSTEM FOR THE CHECK OF CONTINUITY IN LINE BASED ON SWITCH FIELD OF THE IHVENCIÓH The present invention relates in general to communication systems and, more particularly, relates to a method and a system for verifying continuity in a communications line. More particularly, the present invention relates to a method and a system based on a switch for the verification of the continuity in a telephone line for use in applications such as alarm and security systems.

BACKGROUND OF THE INVENTION In modern society, alarms against thieves, fire alarms and other alarms that monitor security have become common. Competition for customers or subscribers has become very fierce among alarm service providers. Alarm service providers who can provide a fast and effective alarm service at a low price have the best chance of surviving in this competitive environment. In this way, alarm service providers are looking for ways to provide a cheaper, faster and more cost-effective service.

P1699 / 99MX more effective to its customers. A typical alarm system includes a subscriber terminal unit (hereinafter STU by its acronym in English), located at the customer premises. The STU can be connected to several different alarm detectors located throughout the client's premises. The STU connects to the alarm service provider through a telephone line. When necessary, the STU performs several tasks by sending signals to the alarm service provider and receiving signals from the alarm service provider over the telephone line. The alarm service is not possible if the telephone line is cut or malfunctioning, because the signals can not be sent back and forth between the alarm service provider and the STU. Therefore, most of the alarm service providers verify the continuity of the telephone line connected to the STU, that is, they monitor that the telephone line is operating properly, because the telephone line is critical for a telephone line. effective alarm service. Systems are known that verify the continuity of a telephone line connected to an STU. In a known system, designed to be used with a copper twisted pair transmission medium, the subscriber terminal unit (STU) transmits P1699 / 99MX a tone of low constant frequency or low tone in the future (LT for its acronym in English), on the twisted pair of copper to the public telephone exchange. When the LT is no longer detected in the public telephone exchange, such as, for example, when the telephone line is cut, or: (1) the alarm service provider is notified of a problem or (2) the telephone exchange public sends a return signal to the STU to determine the problem with the STU. For example, U.S. Patent No. 4,741,022 to Chebra et al., Discloses an interaction system with the remote subscriber that includes a scanner that can monitor the low tone signals transmitted by an STU, to detect alarms or malfunctioning. the line. In the event that a dangerous condition or an alarm is detected, production of the low tone signal in the STU is interrupted. A scanner can detect this interruption of the low tone signal and interrogate the STU. The STU can answer this question by providing information about the reason for the observed phenomenon, such as the origin of the danger or alarm. The browser can reset or reset the STU to resume transmission of the low tone signal. Although the system described above for transmitting and monitoring a low tone works when P1699 / 99MX the transmission medium is strictly a copper twisted pair, many new transmission links are digital. Problems are encountered when the transmission medium includes a digital transmission link, because the low tone is filtered out. In this way, alternative systems have been developed to verify the continuity of the customer's telephone line, for use with digital loop carriers (hereinafter sometimes also called DLCs), such as the system shown in Figure 1. Figure 1 is a block diagram illustrating a known system 100 for verifying the continuity of a telephone line for use by a non-integrated digital loop system. A non-integrated digital loop system includes a digital transmission link but, the digital transmission link terminates at a main dispatcher before reaching a switch. The system 100 includes a telephone set 105 and a subscriber terminal unit (STU) 110, each of which is connected to a network interface 115 via a telephone line 117. Both the telephone set 105 and the STU 110 are located at the customer's premises. The network interface 115 is connected to the remote terminal 120 by the twisted pair 125. The twisted pair 125 terminates in a first P1699 / 99MX line unit 130 of the remote terminal 120. The remote terminal 120 is connected to the terminal of the public telephone exchange 135 by the digital loop 140. A second line unit 145, located in the terminal of the public telephone exchange 135 is connected to a main splitter (hereinafter referred to as MDF by its acronym in English) 150 through the twisted pair 155. The main splitter 150 is connected to a scanner 160 and a switch 165 by the twisted pairs 170 and 175 respectively. Although only one scanner is shown in Figure 1, there may be numerous scanners, associated with several different alarm service providers, connected to the MDF 150. As described above, when the transmission medium is strictly a copper twisted pair, the STU transmits a constant low tone (LT) over the copper twisted pair to the telephone exchange. However, when the transmission medium includes a digital transmission link, such as the digital loop 140 of FIG. 1, the low tone is filtered out in the remote terminal 120 due to its low frequency. Therefore, to overcome this problem the system 100 shown in Figure 1 was developed. The system 100 shown in Figure 1 operates as follows. The STU 110 includes a generator Low-tone P1699 / 99MX (not shown) transmitting on the telephone line 117 and the twisted pair 125 a low-frequency or low-tone (LT) tone. The first line unit 130 (LU) monitors the low tone of the twisted pair 125. The remote terminal 120 encodes a signaling bit ported between the remote terminal 120 and the public central telephone terminal (COT). English) 135 over digital loop 140. The signaling bit is coded 11O to indicate whether or not the first line unit 130 received the LT. The COT 135 monitors the signaling bit and instructs a low-tone generator (not shown) in the second LU 145 to either transmit an LT or do not transmit an LT. If the signaling bit indicates that the LT was received by the first LU 130, then the low tone generator of the second LU 145 is instructed to transmit the LT. The second LU 145 transmits the LT for the pair braided 155 and the twisted pair 170 to the scanner 160. The scanner 160, monitored by the alarm service provider, detects the LT to verify the continuity of the telephone line 117. However, if the signaling bit indicates that the first LU 130 did not receive the LT, then the low tone generator of the second LU 145 does not transmit the LT. The scanner 160 then detects that the LT is not being generated and that the P1699 / 99MX telephone line 117 has been cut or has some kind of malfunction. The alarm service provider then initiates a telephone call to the STU 110 in an attempt to determine the nature of the failure. The system 100 described above with reference to Figure 1, works with non-integrated digital loop carriers. However, for integrated digital loop carriers, the system 100 does not work properly, because there is no public telephone exchange terminal between the remote terminal and the switch to recognize the signaling bit. In addition, the switch can not recognize the signaling bit that indicates whether the low tone was received. In this way, a system 200 shown in Figure 2 was developed to monitor the continuity of the line when the transmission medium includes an integrated digital loop carrier. Figure 2 is a block diagram illustrating a known system 200 for verifying the continuity of a telephone line when the transmission medium includes an integrated digital loop carrier. The telephone apparatus 205 and the subscriber terminal unit (STU) 210 are connected to the network interface 215 via the telephone line 217. The network interface 215 is connected to the remote terminal 220 via the twisted pair 225. The P1699 / 99MX twisted pair 225 terminates in a first line unit 230 of the remote terminal 220. The remote terminal 220 is connected to the digital interconnection system (DACS) 235 by means of the digital loop 237. The DACS 235 is connected to the terminal dedicated to the public telephone exchange 240 by means of the digital loop 242. The DACS 235 is also connected to the switch 245 by means of the digital loop 247. A second line unit (LUC) 249, in the dedicated terminal of the public telephone exchange 240 is connected to the main splitter 250 by means of the twisted pair 252. The MDF 250 is connected to a scanner 255. By means of the twisted pair 257. In the system 200, the STU 210 generates a low tone (LT) which is transmitted over the telephone line 217 and twisted pair 225 to the first line unit (LU) 230. Remote terminal 220 codes one of the signaling bits that is transmitted by digital loop 237 to DACS 235. The signaling bit coded indication indicates whether the first LU 230 received the low tone or not. In the DACS 235, the digital loop channels 237 that are associated with an alarm service provider are extracted and sent over the digital loop 242 to the dedicated terminal of the public telephone exchange 240. The dedicated terminal of the public telephone exchange 240 monitor the bit P1699 / 99MX coded signaling. Yes, based on the coded signal bit, it is determined that the first LU 230 received the low tone, then, a low tone generator in the second LU 249 generates a low tone that is sent to the MDF 250 and the browser 255. However, if it is determined that the first LU 230 did not receive the low tone, then the tone generator b jo of the second LU 249 is deactivated and the low tone is not transmitted to the browser 255. The browser 255 then detects the loss of the low tone and the alarm service provider is connected to the STU 210 by a telephone call. The cost of the system 200 is large, due to the expense in equipment such as the DACS 235, the dedicated TOC 240 and the MDF 250. In addition, the systems 100 and 200 described above suffer from the lack of speed in the recognition of the loss of the low tone signal. In emergency situations, the seconds can be critical. Sometimes, the seconds that are lost while the explorer receives the loss of the LT, recognizes it and determines the problem, can be detrimental to the effective handling of the emergency. One reason that seconds are lost is that it often takes several seconds before the LT loss is received by the scanner, due to the number of components in these systems. The explorer also requires several seconds to recognize the loss P1699 / 99MX of the LT. In addition, it may take several seconds for the alarm service provider to connect to the STU to interrogate the STU and determine the problem with the STU. Thus, in the art there is a need for a system to verify the continuity of a telephone line that is faster, more efficient and less expensive than previous systems. Thus, there is a need in the art for an improved system for verifying the continuity of a telephone line for use with an integrated digital loop transmission medium. Additionally, there is a need in the art for a system to verify the continuity of a telephone line that does not require a dedicated terminal of a public telephone exchange. There is a further need in the art for a system to verify the continuity of a telephone line that does not require a main dispatcher.

SUMMARY OF THE PRESENT INVENTION As will be appreciated, the present invention satisfies the foregoing criteria. Stated in a general manner, the present invention provides a system and method for verifying the continuity of P1699 / 99MX a connection between a monitored premises and a safety network. More particularly, in one modality, the method is to verify the continuity of a connection between a monitored site and a safety network in a safety monitoring environment. A subscriber terminal unit in a monitored premises transmits a signal on the connection to the safety net. The signal represents that the monitored site is safe. A line unit in a remote terminal of the safety net can monitor the reception of the signal. If the line unit does not receive the signal, then the line unit codes a signaling bit that represents that the monitored site is not secure. The line unit transmits the signaling bit, also known as coded signaling bit or signaling bit with condition or low tone state, to a switch. Alternatively, a line unit in a switch can monitor the reception of the signal. In response to receiving the signaling bit, the switch sends an identification of the monitored location to a scanner of the safety net. The explorer is then connected to the monitored premises. Alternatively, the scanner can be immediately connected to the monitored premises, through a trunk circuit, and then, the switch can send the number of P1699 / 99MX directory associated with the monitored premises. In one embodiment, the step of connecting the scanner to the monitored premises is accomplished by creating a temporary bridge to connect the browser to the subscriber terminal unit. In another mode, the step of connecting the scanner to the monitored premises is carried out using a switch connection. In another additional embodiment, the signal is a low tone signal that is transmitted over the telephone line. In another embodiment, the coded signaling bit is an ABCD signaling bit. In still another embodiment, the present invention is a method for verifying the continuity of a telephone line connected to a subscriber terminal unit. A low tone generator of the subscriber terminal unit transmits a low frequency tone, preferably thirty-six Hertz, which is monitored by a line unit. The line unit can be located in a remote terminal or in a switch. The line unit encodes at least one signaling bit, preferably an ABCD signaling bit, to indicate whether or not the low frequency tone was received and sends the encoded signaling bit to a switch on the digital loop carrier. The switch determines whether the signaling bit P1699 / 99MX encoded indicates that the low frequency tone was not received. If so, the switch transmits to a browser a directory number that corresponds to the telephone line. The switch can transmit the out-of-band directory number by sending the directory number associated with the office connection equipment via an SS7 or SMDI link. The browser uses the directory number to interrogate the subscriber terminal unit. In one embodiment, the browser may interrogate the subscriber terminal unit by making a direct or bridged connection without calling, by means of enhanced UTT trunks. In an alternative embodiment, the method further includes the step of determining whether a hanger signal was received or not in response to interrogation of the subscriber terminal unit. In another embodiment, the method also includes the steps of determining whether the telephone line is in use, and, if so, of connecting the telephone line to the browser by creating a temporary bridge between the browser and a trunk group. In still another embodiment, the present invention is a system for verifying the continuity of a telephone line. The system includes a subscriber terminal unit and a low tone generator that operates to generate a low frequency tone that is transmitted over the telephone line.

P1699 / 99MX The system also includes a line unit connected to the subscriber terminal unit via the telephone line. The line unit determines whether or not the low frequency tone from the low tone generator was received. The system also includes a remote terminal that encodes a signaling bit as an encoded bit. The encoded bit is indicative of whether or not the line unit receives the low frequency tone. The system includes a digital loop carrier that connects the line unit with a switch. The digital loop carrier transmits the coded bit to the switch. The system also includes a scanner connected to the switch. In still another embodiment, the system of the present invention includes an alarm detector connected to the subscriber terminal unit. The alarm detector sends alarm signals to the subscriber terminal unit. The subscriber terminal unit detects and responds to the alarm signal by instructing the low tone generator to stop generating the low frequency tone. The present invention is an improvement over the prior art systems, to notify the alarm service providers. The system of the present invention connects only the scanner to the STU. The system can also send the scanner the number of P1699 / 99MX Subscriber phone line directory, so that the browser immediately knows the identity of the customer premises. The scanner can then interrogate the STU immediately. Alternatively, the system can immediately connect the subscriber terminal unit to the scanner, via a non-call connection through a direct or bridged trunk circuit. The switch of the system of the present invention is faster in detecting the loss of low tone than the scanners of the prior art, due to the supercomputing capabilities of the switch. In this way, the speed improves, not only because the components of the prior art systems have been removed but also because of the computing capabilities of the switch. The present invention provides an improved method and system for verifying the continuity of a telephone line connected to a subscriber terminal unit in an alarm system environment. The system of the present invention is less expensive than the systems of the prior art, because fewer components are needed. In addition, the detection speed of the low tone loss is increased, because the loss of the low tone signal travels through a smaller number of components and because the detection of the loss of the low tone is effected by a switch with P1699 / 99MX a supercomputer, instead of with a browser. The present invention also has the advantage that when the loss of low tone is detected, the directory number is transmitted to the browser and the browser is immediately connected to the telephone line, so that the identity of the location of the telephone is immediately known. client and can immediately interrogate the STU as to its status or condition. It is an object of the present invention to provide an improved method and system for verifying the continuity of a telephone line. It is a further object of the present invention to provide a method and system for verifying the continuity of a telephone line that is faster, more efficient and less expensive than current systems. It is also an object of the present invention to provide a method and system that does not require a dedicated terminal of the public telephone exchange. It is also an object of the present invention to provide a method and system that do not require a main distributor. It is an object of the present invention to provide an improved system for verifying the continuity of a telephone line, for use with a digital loop transmission medium P1699 / 99MX integrated. It is a further object of the present invention to provide a system for verifying the continuity of a telephone line that does not require a main distributor. Other features and advantages of the present invention will be apparent to those skilled in the art from the following detailed description of a preferred embodiment, accompanied by the accompanying drawings, in which identical reference numbers will refer to similar parts and steps in the different views.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram illustrating a known system for verifying the continuity of a telephone line for use with a non-integrated digital transmission link. Figure 2 is a block diagram illustrating a known system for verifying the continuity of a telephone line for use with an integrated digital transmission link. Figure 3 is a block diagram of the preferred system of the present invention for monitoring the continuity of a telephone line. Figure 4 is a flow chart illustrating the preferred method of the present invention. Figure 5 is a flow diagram that P1699 / 99MX illustrates an alternative embodiment of the method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED MODE Described in a general manner, the present invention provides a method and system based on a switch for the verification of the continuity of a telephone line. More particularly described, the present invention preferably provides a method and system, based on a switch, to verify the continuity of a telephone line by monitoring a signaling bit in the context of an alarm system. Briefly described, the preferred system of the present invention includes a switch that monitors a signaling bit with condition or low tone state from a remote terminal for loss of low tone indication. The switch recognizes the loss of the low tone indication in the signaling bit with low tone status. Then, the switch or: (1) automatically connects a browser to the subscriber terminal unit (STU) and sends the browser a directory number or (2) sends a directory number to the browser, so the browser can try connect to the STU by means of utility telemetry trunks or improved UTT trunks.

P1699 / 99MX In an embodiment of the present invention, when it is set or set to signaling bit with low tone state, so that it indicates the loss of low tone, the switch connects the subscriber's telephone line, through a default trunk group to the browser. The switch determines whether or not the subscriber's telephone line is in use, such as, for example, when the subscriber is holding a telephone conversation over the telephone line. If the subscriber's telephone line is in use, then a temporary bridge from the browser to the trunk group is created to connect the browser to the subscriber's telephone line. If the subscriber's telephone line is not in use, then the subscriber's telephone line is preferably connected to the browser through a trunk group. Preferably, the connection between the scanner and the subscriber's telephone line is a call-free connection, as is known to those skilled in the art. After the browser is connected to the subscriber's telephone line, either through the use of the temporary bridge or the direct trunk group, the switch can transmit to the browser, preferably in band, the telephone number directory of the subscriber . The scanner can then interrogate the STU immediately, about the state of the STU. A P1699 / 99MX status interrogation of the STU can include the determination of whether the STU has received any alarm conditions from the alarm detectors and determine whether the subscriber's telephone line is functioning properly. After determining the status of the STU, the browser preferably sends a hang signal to the switch. The switch then interrupts the connection between the STU and the browser. If the switch does not receive the hang signal, then the connection timeout will be between the STU and the browser in the predetermined amount of time. In an alternative embodiment of the present invention, when the low tone state signaling bit indicates loss of low tone, the switch preferably sends the directory number of the subscriber's telephone line to the browser via an SMDI link or another solution or network address, using the signaling system protocol 7 (SS7). The SS7 protocol is well known to those skilled in the art and is described in a specification given by the American National Standards Institute (ANSI). After receiving the directory number from the subscriber's telephone line, the browser may attempt a direct or bridged connection without calling the STU through enhanced UTT trunks. A Once P1699 / 99MX is connected, interrogation of the state of the STU is performed. Having briefly described the present invention, a more detailed description of the present invention with respect to Figures 3 to 5 is presented below. Figure 3 is a block diagram of the preferred system 300 of the present invention for monitoring the continuity of a telephone line. The system 300 includes a telephone device 305 and a subscriber terminal unit (STU) 310 located in the customer's premises that has subscribed an alarm service. The telephone set 305 is a conventional telephone, as is known to those skilled in the art. The STU 310 is connected to one or more alarm detectors 312, located throughout the customer premises. When an alarm detector 312 detects an alarm condition, such as a fire or a broken window, it sends an alarm signal to the STU 310, so that the STU 310 can notify the alarm to the service provider. The STU 310 is the customer premises equipment, that is, a piece of equipment that is connected to the telephone network and is located in the customer's premises. The STU 310 includes a low-tone generator 313 that generates a constant low-frequency tone P1699 / 99MX or low tone (LT). The LT preferably has a frequency of 36.5 Hz and is inaudible to the human. In this way, the LT does not interfere with the sounds transmitted by the telephone line 317. The LT is transmitted to the alarm service provider, as described more fully below, to ensure the alarm service provider that the STU it is functioning properly and that the telephone line 317 connected to the STU has not been cut by an intruder. Alternatively, the low tone may also indicate that the STU 310 has not received alarm conditions from the alarm detectors 312. The telephone set 305 and the STU 310 are connected to the network interface 315 via the telephone line 317. The STU 310 transmits the LT over the telephone line 317. The network interface 315 is the point of interconnection between the communication facilities of the telephone company (or the service provider) and the customer's premises. The network interface is preferably a modular plug, well known to those skilled in the art. The network interface 315 is connected to the line unit 320 by a copper pressing pair 325. The line unit 320 is associated with a remote terminal 330. The line unit 320 includes the function for monitoring the LT generated by the P1699 / 99MX low-tone generator 313 of the STU 310. The remote terminal 330 is an analog-to-digital transition point connecting the copper twisted pair 325 and the digital loop 340. The remote terminal 330 is connected to a switch 335 by the digital loop 340. The digital loop 340 is preferably a digital transmission link Tl, as is known to those skilled in the art. A digital transmission link of T-l has a bandwidth of 1,544 Mbps, which normally includes twenty-four digitized voice conversations at 64 Kbps each. In addition to the twenty-four voice channels, many T-l digital transmission links use bits, known as ABCD signaling bits, which are taken from the bytes in each T-l channel. ABCD signaling bits are normally used to carry status information. Although digital loop 340 is preferably a digital transmission link T-1, digital loop 340 may be another type of digital transmission link known to those skilled in the art. The switch 335 is a typical digital telecommunications switch, as is well known to those skilled in the art. However, the switch 335 has been programmed with an additional functionality or function, which will be described later in greater detail. He P1699 / 99MX switch 335 is preferably located in a public telephone exchange. Those skilled in the art will also recognize that the line unit 320 could be located on the switch 335. Referring still to Figure 3, the switch 335 is connected to a scanner 345 or other monitoring device, via the trunk group 350 and the Messaging Desktop Simplified Interface link or SMDI 335 link. A SMDI link is a low speed link to a switch for use with the voice mail system to send requests for an intermittent dial tone. Scouts, such as scout 345, are well known to those skilled in the art. The browser 345 is preferably located in the installation of the alarm service provider and is preferably operated and maintained by the alarm service provider. However, the browser 345 could be maintained in a public telephone exchange together with the switch 335. The browser 345 is used to monitor the customer premises by sending sls to the STU 310 and receiving the sls from the STU 310. Having briefly described the components of the system 300, the preferred operation of the system 300 will now be described in greater detail. The low tone generator 313 in the STU 310 generates a P1699 / 99MX low tone (LT), below the audible range, which is transmitted over the telephone line 317 through the network interface 315 over the twisted pair 325 to the line unit 320. Preferably, the generated LT by the STU 310 it has a frequency of approximately thirty six Hertz. The LT is generated continuously but can be interrupted if the telephone line 317 is cut or has a fault. The LT can also be interrupted if an alarm detector 312 detects an alarm condition. The line unit 320 has the function, as is known to those skilled in the art to verify that the LT is being received on the twisted pair 325. As long as the LT is received by the line unit 320, the remote terminal 330 encodes a low tone state sling bit to indicate that the LT is being received by the line unit 320. If the LT is not received by the line unit 320, then the remote terminal 330 codes the sling bit low tone state to indicate that the LT is not being received by the line unit 320. For example, the low tone state sling bit may be coded to be a binary one indicating that the low tone was received and coded for It is a binary zero that indicates that the low tone was not received or vice versa. Preferably, the bit of P1699 / 99MX low tone state sling is bit "B" of sling bits ABCD of digital loop 340, however, another available sling bit could be used to indicate low tone status, ie, if received or not the low tone. The low tone state sl bit is transmitted by the digital loop 340 together with the voice channel and control channels of the digital loop 340. The switch 335 contains the function, i.e. is programmed, to allow the switch to monitor the low tone status sling bit. If the low tone status sl bit indicates that the LT was received by the line unit 320, then the switch 335 does not send any indication to the scout 345 because the continuity of the telephone line 317 has been verified. , if the telephone line 317 has been cut off, if the STU 310 has been violated so that the STU no longer generates the LT or, if the low tone has been "shorted" to indicate an alarm condition, then the line unit 320 does not receive the LT. The remote terminal 330 codes the low tone state sling bit to indicate that the LT has been lost, ie, it is no longer received by the line unit 320. The switch 335 then receives the bit preferably P1699 / 99MX low-tone signaling indicating that the LT has been lost and notifying the scout 345 in one of two ways. In a notification method, the switch 335 preferably determines whether the telephone line 317 of the subscriber is in use or not. If this is the case, a temporary bridge (not shown) of the browser 345 is created to the trunk group 350 to connect the browser 345 to the subscriber's telephone line 317. If the subscriber's telephone line is not in use, then the switch 335 preferably connects the telephone line 317 of the subscriber with the browser 345 through the trunk group 350. In any case, the connection is preferably a connection without calling, such as is known to those skilled in the art. After the browser 345 connects to the subscriber's telephone line 317, either via a temporary bridge or a trunk 350, the switch 335 transmits the directory number of the telephone line 317 to the browser 345. The browser 345 can then interrogate to STU 310 with respect to STU status. After determining the state of the STU 310, the browser 345 sends a hang signal to the switch 335 and the switch interrupts the connection between the trunk group 350 and the browser 345. The present invention is an improvement with P1699 / 99MX with respect to prior art systems for notifying the alarm to service providers. The present invention connects only the scanner to the STU. The present invention also preferably sends the directory number of the subscriber's telephone line to the browser, so that the browser immediately knows the identity of the client's premises. The scanner can then interrogate the STU immediately. The switch is faster to detect low pitch loss than in the prior art scanners, due to the supercomputing capabilities of the switch. In this way, the speed is increased, not only because the components of the systems of the prior art have been eliminated but also due to the computing capabilities of the interrupt. The present invention includes a second method of notification. In this second notification method, the switch 335 preferably sends the directory 345 of the out-of-band subscriber telephone line to the browser 345 via the SMDI link 355. Those skilled in the art will appreciate that an SS7 link can be used instead of the link. SMDI 355. After receiving the directory number, the browser 345 connects to the STU 310 via a switch connection. Preferably, the browser is connected to the STU by a P1699 / 99MX direct connection or bridged without calling through enhanced UTT trunks. Once connected, the browser 345 interrogates the STU 310 to determine its status. This method of notification includes the advantage of quickly notifying the browser of the directory number of the telephone line, so that the browser can immediately take action, such as notifying a patrol in the customer's premises area or connecting the STU and interrogate the STU regarding the problem at the client's premises. The SMDI link 355 is several times faster to transmit the directory number than the trunk group 350. This second faster notification is advantageous in some emergency situations. The notification using the SMDI link 355 is also advantageous, because there is usually a limited number of trunks in the trunk group 350. Thus, if many different subscribers of the alarm service suffer the loss of the low tone at the same time, then trunk group 350 may become saturated. The notification using the SMDI 355 link provides an alternative notification method in this saturation situation. The preferred methods of the present invention are described below with reference to Figures 4 and 5. Figure 4 is a flow diagram illustrating the preferred method of the present invention.

P1699 / 99MX invention. Method 400 starts at start step 405. The method proceeds to step 410 when switch 335 starts to receive bits, which include the low tone state signaling bit, over digital loop 340. At decision step 415 , it is determined if the low tone has been lost or not. Preferably, the low tone state signaling bit indicates whether the low tone has been lost. If the low tone status signal bit indicates that the low tone has not been lost, then the method returns to step 415 to determine once more whether or not the low tone has been lost. If, in decision step 415, it is determined that the low tone has been lost, then the method proceeds to decision step 420. The determination is made as to whether the subscriber's telephone line 317 is in use at decision step 420. If, at decision step 420, it is determined that the subscriber's telephone line is in use, then a temporary bridge from the browser to the trunk group is created in step 425. However, if, in decision step 420, it is determined that the subscriber's telephone line is not in use, then the subscriber's telephone line is connected to the explorer in step 430. After the temporary bridge to the trunk group is created in step 425 or the subscriber's telephone line is connected to the browser in step P1699 / 99MX 430, then the method proceeds to step 435 and the directory number of the subscriber's telephone line is transmitted to the browser. The browser interrogates the STU with respect to the state of the STU in step 440. Preferably the STU sends a hanger signal to the switch when the browser has terminated its interrogation to the STU. It is determined whether the switch has received the hang signal, in decision step 445. If so, then the method ends in step 450. If not, then the method returns step 445 to continue monitoring the hanging signal. Alternatively, if the switch did not receive the hang signal, then the connection between the STU and the browser will time out in the predetermined amount of time. Referring now to Figure 5, a flow diagram illustrating an alternative embodiment of the method of the present invention is described. The method 500 starts at the start step 505 and proceeds to step 510 when the switch 335 begins to receive bits preferably through the digital loop 340 (Figure 3). In decision step 515, it is determined whether the low tone state signaling bit indicates whether the low tone has been lost or not. If the low tone status signal bit indicates that the low tone has not been lost, P1699 / 99MX then the method returns to decision step 515 to continue monitoring the low tone state signaling bit. If, in decision step 515, it is determined that the low tone has been lost, then the method proceeds to step 520. In step 520, the directory number of the subscriber's telephone line is transmitted to the browser. The switch can send out of band the directory number associated with the subscriber's telephone line via an SS7 or SMDI link. The method then proceeds to step 525, where the browser attempts to establish a call without calling the STU through enhanced UTT trunks. In step 530, the browser interrogates the STU with respect to the state of the STU. After the browser has interrogated the STU in step 530, the method in step 535 terminates. Those skilled in the art will recognize that, although the low tone state signaling bit is preferably signaling bit "B" of ABCD, other bits could be used as signal bit for the low-tone state. In addition, other indications other than those of the low tone state signal bit, such as for example a series of pulses, could be used to indicate the low tone state, without deviating from the spirit and scope of the present invention.

P1699 / 99MX The present invention provides an improved method and system for verifying the continuity of a telephone line connected to a subscriber terminal unit in an alarm system environment. The system of the present invention is less expensive than the systems of the prior art, because fewer components are needed. In addition, the detection rate of the tone loss increases because the low tone loss signal travels through a smaller number of components and, because the detection of the low tone loss is made by a switch with a supercomputer, instead of an explorer. The present invention also has the advantage that when the loss of low tone is detected, the directory number is transmitted to the scanner and the browser is immediately connected to the telephone line, so that the identity of the location of the telephone is immediately known. client and you can immediately interrogate the STU about its status. Given the above discussion of the preferred embodiment and design parameters of the present invention, other embodiments of the present invention will be suggested to those skilled in the art. Therefore, the scope of the present invention will be limited only by the following claims.

P1699 / 99MX

Claims (17)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1. In a security monitoring environment, a method to verify the continuity of a connection between a monitored premises and a security network, comprising the steps of: causing a subscriber terminal unit in the monitored premises to transmit a signal on the connection to the safety net, the signal representing that monitored site is insurance; causing a line unit in a remote terminal of the security network to monitor the reception of the signal coming from the subscriber terminal unit in the connection; if the signal is not received by the line unit, then have the line unit code a signaling bit to represent that the monitored site is not secure; causing the line unit to transmit the signaling bit to a switch of the safety network; in response to receiving the signaling bit, have the switch send the scanner of the security network an identification of the monitored location; Y P1699 / 99MX connect the scanner to the monitored premises to interrogate the subscriber's terminal unit.
2. 2. The method according to claim 1, in > wherein the step of connecting the scanner to the monitored premises further comprises creating a temporary bridge to connect the scanner to the subscriber terminal unit. The method according to claim 1, wherein the step of connecting the browser to the monitored premises further comprises causing the browser to connect to the subscriber terminal unit using a switch connection. 4. The method according to claim 1, wherein the connection is a telephone line; where the signal is a low tone; and wherein the step of causing the subscriber terminal unit to transmit the signal further comprises causing the subscriber terminal unit to transmit the low tone over the telephone line. The method according to claim 1, wherein the signaling bit is a signaling bit ABCD; and wherein the step of having the line unit code the signaling bit representing that that monitored location is not secure further comprises having the unit line code the signaling bit ABCD to represent the location P1699 / 99MX monitored is not safe. 6. A method for verifying the continuity of a telephone line connected to a subscriber terminal unit, comprising the steps of: i causing a low tone generator of the subscriber terminal unit to transmit a low frequency tone; causing the line unit to monitor reception of the low frequency tone from the subscriber terminal unit; causing the line unit to code at least one of a multitude of signaling bits to indicate whether or not the low frequency tone was received; causing a switch to receive at least one bit of the multitude of signaling bits on a digital loop carrier from the line unit; causing the switch to determine if the at least one bit of the plurality of signaling bits indicates that the low frequency tone was not received; if so, have the switch transmit to a browser a directory number corresponding to the telephone line; and having the browser use the directory number to interrogate the subscriber terminal unit. 7. The method according to claim 6, which P1699 / 99MX further comprises the step of determining whether the hang signal has been received in response to interrogation of the subscriber terminal unit. The method according to claim 6, wherein the multitude of signaling bits are signaling bits ABCD; and wherein the step of making the line unit encode the at least one bit of the multitude of signaling bits to indicate whether or not the low frequency tone was received, further comprising making the line unit encode the at least one bit of the multitude of signaling bits ABCD to indicate whether or not the low frequency tone was received. The method according to claim 6, wherein the low frequency tone has a frequency of 36.5 Hertz and, wherein the step of causing the low tone generator of the subscriber terminal unit to transmit the low frequency tone, it further comprises causing the low tone generator of the subscriber terminal unit to transmit the low frequency tone at the frequency of 36.5 Hertz. The method according to claim 6, further comprising the steps of: following the step of having the switch determine if at least one bit of the multitude of signaling bits indicates that the tone of the signal was not received. P1699 / 99MX low frequency, then determine if the telephone line is in use; and if the telephone line is in use then connect the telephone line to the browser. > The method according to claim 10, wherein the step of the connection further comprises the step of: if the telephone line is in use, then create a temporary bridge between the browser and a trunk group. 12. A system for verifying the continuity of a telephone line, comprising: a subscriber terminal unit; a low tone generator associated with the subscriber terminal unit, the low tone generator operates to generate a low frequency tone that is transmitted over the telephone line; a line unit connected to the subscriber terminal unit by the telephone line, the line unit operates to determine if the low frequency tone from the low tone generator was received; a remote terminal, associated with the line unit, the remote terminal operates to encode at least one bit of a multitude of signaling bit as a coded bit, the coded bit is indicative of whether the line unit received the tone P1699 / 99MX low frequency; a digital loop carrier that connects the line unit with a switch, the digital loop carrier operates to transmit the encoded bit > to the switch; and a scanner connected to the switch. The system according to claim 12, wherein the low frequency tone is below the audible range. The system according to claim 12, wherein the low frequency tone is a tone of 36 Hertz. The system according to claim 12, wherein the subscriber terminal unit is connected to an alarm detector. The system according to claim 15, wherein the alarm detector operates to send an alarm signal to the subscriber terminal unit; wherein the subscriber terminal unit operates to detect and respond to the alarm signal by providing instruction to the low tone generator to stop the generation of the low frequency tone; and where the low tone generator responds to the instruction to stop the generation of the low frequency tone. 17. The system according to claim 12, P1699 / 99MX further comprising a trunk group connecting the switch to the scanner; and a SMDI link that connects the switch to the browser. P1699 / 99MX SUMMARY OF THE INVENTION In an alarm and security service environment, a method and a system for verifying the continuity of a telephone line (317) connected to a subscriber terminal unit (STU for its acronym in English) is disclosed. ) (310) in a local of a client. The STU (310) is connected by telephone line (317) to a network interface (315) which is connected to a line unit (320) by means of a twisted double lead (325). The line unit (320) is located at the remote terminal (330) which is connected to the switch (335) by means of a digital loop (340). The switch (335) is connected to the browser (345) by the trunk group (350) and the SMDI link (355). A low tone generator in the STU (310) generates a low frequency tone that is transmitted to the line unit (320). If the telephone line (317) is cut, if there are malfunctions in the STU (310) or if the STU (310) detects an alarm condition in the customer premises, then the low tone is not received by the line unit ( 320). The remote terminal (330) encodes a signaling bit that is transmitted over the digital loop (340) to the switch (335). The encoded signaling bit indicates whether or not the low tone was received by the line unit (320). The switch (335) reads the coded signaling bit and, if the signaling bit P1699 / 99MX encoded indicates that the low tone was not received, sends a directory number to the browser (345). The switch (335) connects the scanner (345) to the telephone line (317) so that the alarm service provider can challenge the STU (310) to determine the problem. P1699 / 99MX