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FIELD OF THE INVENTION
This invention relates generally to an electronic device used in telecommunication field for continuous monitoring and alarm apparatus for telephone cable, and more specifically to an apparatus for continuously and efficiently monitoring the status and health of multi pair copper telephone distribution cable laid in the field, from main distribution frame of telephone exchange up to distribution panel (DP) box and activating an audio-visual alarm if the telephone cable becomes inoperative due to intentional or accidental disruption of telephone service.
BACKGROUND OF THE INVENTION
Telephone service to a subscriber may be disrupted as a result of a malfunction occurring on the utility-provided central office line or on-premise subscriber line. A telephone line may become inoperative due to accidental breakage or shorting, as may occur from inclement weather, or through deliberate action, such as during a burglary in which the on-premise subscriber line is cut to disconnect an alarm system from a central monitoring station or prevent a victim from calling for assistance, or cutting the cable and stealing DP box to reprocess and sell them inform of raw materials. Regardless of the cause of the disruption, the telephone subscriber will be without telephone service and will in general, even service provider may not be aware that the telephone cable is inoperative. It is therefore desirable to have a simple and reliable telephone cable monitor and alarm means which functions to continuously monitor the integrity of the telephone cable up to DP box and alert the exchange personnel by both visual and auditory signals if a disruption in telephone service occurs.
For each telephone subscriber, one pair of line is laid from the telephone exchange, to telephone instrument via main distribution frame (MDF), distribution panel box (DP) etc. When cable theft / complete cable cut occurs the entire subscriber lines

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beyond that point are dead. The subscriber complaints to the exchange about non-functioning of his phone, even he may not be aware of the cable cut / theft cases has already taken place. After receiving the complaint only, exchange people checks from MDF room, to confirm the line condition, using instrument like continuity tester, insulation tester etc. It ma show either line is open or short. This may be due to various reasons. This is done as and when the complaint is received. There is no continuous monitoring of the cable health, since manual testing of individual subscriber line is required. With modern electronic exchange, it is possible to know the status of the line, by software, but to conclude from these data, about cable cut / theft is not possible, unless mass fault of particular area is observed / displayed. Then the exchange sends a lineman to the nearest consumer junction box, from where line is extended, for physical check up and does the needful. If all the lines are dead, he has to go to the previous junction box and check it from there. In this process lot of time is lost, particularly in the night time to follow up in the field may not be possible. The thief can easily escape causing lot of damage. If there is no complaint from the subscriber side about the line fault, chances of the exchange attending from their own side might not be there due to their heavy load and non availability of suitable indicative gadgets. Our gadget aims to fulfill this gap..
After studying the above loop holes (no continuous monitoring of cable, checking the system manually line by line after complaint is received, even line status is known by software it cannot distinguish between line open circuited or cable cut, display of the line status needs exclusively a monitor, one cannot say confidently between which two junction box the cable cut occurred, and no audio alarm), we made the device to give continuous monitoring of the field cable up to any DP box, of strategic points from the MDF room (which is manned round the clock in exchange) and gives instant warning of cable cut with audio visual alarm with zonal area. Hence MDF operator can take prompt action to avoid further damage etc. Our system is completely hardware based (no software), portable and suitable for any number of multiple pair copper cables drawn from exchange to any DP box works on simple principie. It needs a free pair from the previous, subsequent junction box and the

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junction box to be monitored from MDF room. This device is very much useful for the private telephone service provider, EPABX owner covering large areas, government run exchange to detect instant theft / complete cut of telephone cable from exchange MDF room in turn can take prompt action to restore the same. Therefore, in continuous telephone cable-monitoring applications, it is desirable to provide a simple and reliable means for continuously monitoring telephone cable status and activating an audio-visual alarm if the telephone cable becomes inoperative. Moreover, telephone cable monitoring and alarm apparatus must incorporate audio-visual status signaling means and ON status indicating means to be effective in positioning the fault areas.
For example a multi pair telephone cable say 5 pair means a cable is made from 10 Nos. independent insulated copper wire of size 0.5 mm (this may vary) diameter, made to form 5 pairs, bundled together with over all PVC protection. It may /may not have armored protection. Each pair we call as telephone line in this write up exclusively each pair meant for one subscriber. One end of cable is always terminated in DP box where as other end is terminated at MDF room. From DP box drop wires are drawn to each individual houses to connect the telephone gadgets .In our patent the device made by us instantly indicated when the telephone cable is fully cut or theft has occurred and not the condition of individual telephone lines. Generally multi pair telephone distribution cable are laid under ground below around 3 feet. Cable theft are mostly done by antisocial elements who cuts the cable and DP box(made of aluminum / fiber) and gets enough time to steal them as there is no device available to give instant information of theft location to exchange people to take prompt action. In turn they process the cable to recover copper/aluminum etc and sell them to earn their lively hood, or knowingly they paralyze communication system with ill intention/motive.
In the case of telephone cable monitoring apparatus intended for continuous use on the exchange premises, the primary objective is to alert the service provider by both visual and auditory means if telephone service is disrupted by line problem due to complete cut or theft. Advances in the current art of continuous telephone cable

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monitoring apparatus are needed in order to meet this objective in a reliable, cost-effective and simple manner based on innovative features, which also enhance product convenience and manner of use.
it is appreciated that numerous telephone line monitors are known in the art. Examples are U.S. Patent. Number. US 5,696,810 to Dunn, U.S. Patent. Numbers US5,056,131 and US4,969,179 to Kanare and Rehler, and U.S. Patent Numbers US4,969,178 to Chen and Loao. In U.S. Pat. No. 5,056,131, there is provided means for activating a self-flashing light emitting diode and an auditory sounder having alternating loud and soft output in response to a detected low voltage fault condition on the telephone line. The monitoring and alarm circuitry is powered by a battery or by an AC source with battery back up, U.S. Pat. No. US4,969,179 discloses a continuous telephone line monitor which activates a light emitting diode and auditory sounder if line voltage falls below approximately 6 VDC, corresponding to a short or open circuit fault condition. In both disclosures connection of the device to the telephone line is made in standard fashion by means of a telephone cable and plug, in U.S. Patent Number US 4, 969,178 a multipurpose subscriber telephone line monitor is provided which uses a voltage detecting circuit, a current detecting circuit, two control circuits and a comparator circuit to detect open-circuit, short-circuit, or illegal connection of the subscriber local line. An alarm circuit is employed to generate an audio alarm signal when the telephone line becomes inoperative.
In summary, the prior art has evolved to provide varied and effective means for continuous telephone line monitoring and alarm activation in response to fault conditions having accidental or deliberate origin and which result in a disruption in telephone service to a subscriber. However, simple and reliable means for connecting a telephone cable monitor to a standard telephone cable, have either not been addressed, nor have involved the use of gadgets which are very simple and easy io make, rellable, versatlle, not uses much external power and no man power.

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SUMMARY OF THE INVENTION
Generally multi pair telephone cables say 50/100/200 pairs etc contains 50/100/200 pairs of lines and are laid from the MDF room of exchange and subsequent distribution depends on the subscriber concentration in the locality. These cables are terminated with suitable termination box at suitable location. Finally each subscriber is connected through a drop wire from that junction box (DP box). That means each subscriber is connected by an exclusive pair of line from exchange as shown in Fig. 1.
A telephone cable monitoring and alarm apparatus for detecting the occurrence of a disruption or loss of telephone service and signaling an audio-visual alarm thereof as
of the cable and alarm functions; interface means to effect connection of said apparatus to the telephone iine; housing assembly means to enclose said eiectricai circuit and interface means; wherein the device is made modular in nature, additionai channels can be added for different zones by simply adding cards.
It is thus an object of the present invention to provide a teleohon cable monitor and
alarm means capable of continuously monitoring cable status upto DP box and activating an audio-visual alarm if the telephone cabie becomes inoperative, said means capable to detect complete cable theft / cut at remote location from the MDF room
It is a further object of the present invention to provide an on line monitoring of the health of the cable.
It is a further object of the present invention to provide a system wherein the system is completely hardware based and no software is involved.

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It is a further object of the present invention to provide a system wherein external power source is needed. The system draws power from the inbuilt source of the teiephone iines from the exchange.
it is a further object of the present invention to provide a system wherein no additional manpower is needed for the operation of the system.
It is a further object of the present invention to provide a simple visual means of ON status indication in said self-contained and autonomous telephone line monitor and alarm means.
It is a further object of the present invention to provide the mechanical configurations
for said self-contained and autonomous telephone cable monitor and alarm means, so as to permit the implementation of said means in a simpie and reliable manner, thereby improving performance while at the same time maintaining a high level of reliability in continuous telephone line monitoring and alarm apparatus. Furthermore the system uses discrete component available in local market, have low cost wherein least maintenance required and is easy to maintain and repair. Therefore it has long life as works on low voltage and current.
To achieve the foregoing objects, and in accordance with the purposes of the invention as embodied and broadly described herein, there is provided an apparatus comprising a mechanicai enciosure and associated electrical circuit.
According to an advantageous embodiment of the present invention the device is
Made modulal in nature, additional channels can be added for different zones by
Simply adding cards.Number of card to be accommodatd depends on the space
Available on the cabinet.

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According to another advantageous embodiment of the of the present invention the device comprises self checking facility of the health of the gadget components, without removing the gadget from service and can be made optional.
According to yet another advantageous embodiment of the present invention is that the audio alarm can be made optional, even if it is not there the cable cut indication can be known from glow of the LED.
According to an advantageous embodiment of the circuit according to the invention is that the gadget can be used as continuity tester.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings, wherein:
FIG. 1 illustrates the distribution system for muiti pair copper telephone cable from MDF room of telephone exchange to the subscriber point, according to the principles of the invention.
FIG. 2 illustrates a simplified electrical block diagram of a single channel telephone cable monitor and alarm apparatus, according to the principles of the invention.
FIG. 3 illustrates a detailed circuit schematic of a preferred embodiment of a telephone Sine (4 channel) monitor and alarm apparatus, according to the principles of the invention.
FIG. 4(a) and 4(b) illustrates a prototype cabinet (front and rear side) for a telephone line (4 channel) monitor and alarm apparatus, according to the principles of the invention.

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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiments of the present invention are now described with reference to the accompanying Figures, wherein the same reference numerals are used for the same elements throughout the various views. The embodiments described herein are by way of example only and merely illustrative of possible embodiments of the principles of the invention. Changes and modifications to these embodiments obvious to one skilled in the art to which the invention pertains are deemed to be within the spirit, scope and extent of the invention as described in
Detail herein and further defined in the appended claims
A generalized multi pair copper telephone cable distribution layout in the field is shown in Fig 1. Number of cable pair from one junction box to subsequent junction box, down the stream generally decreases, In distribution network as the subscriber are given line from the junction boxes. That is the farthest junction box got minimum number and the nearest function box to MDF got maximum number of the pair of lines. Let the junction box A, B. C and E are to be monitored as these are critical areas prone to theft / cut. If sabotage occurs it may paralyze the communication system
The invention basically detects the multi pair copper telephone cable complete cut /
theft at the field from MDF room in the telephone exchange To operate the gadget no additional manpower is required.
The gadget works on the exchange power supply (48V DC). It consists of loop sensor, switching device, visual display LED unit, audio alarm and has provision for
self lesting of the system as shown in Fig. 2. The device hardly draws maximum
20mA DC current per loop channel.Each card takes care of one channel and by
adding number of cards, number of channels / zones can be increased. Our
prototypo model is made for 4 chonnels using 4 indepondent channel cards.

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COMPONENT LIST
BILL OF MATERIAL (USED IN CIRCUIT DIAGRAM, FIG- 3)

sl. No.. Component Name Abbreviation used Function
1 Fuse F1,F2 To protect the circuit against short circuit/over current
2 Double poie single throw switch DPST S To make power ON / OFF to the gadget
3 Diode D To protect circuit against connection of wrong polarity of power supply
4 Resistor R To limit current in LED K
5 Lightemitting diode LED K When gilws indicate power ON condition
6 Terminals N 11, N21 Input pair to gadget for channel 1 i.e. DP box A.
7 Single po!e double throw switch SPDT P 11,P 12 P 13.P 14 To connect actual line or to simulate line condition
8 Resistor R11, R21 R12,R22 R13,R23 R14,R24 Used as potential divider
9 Diode D 11,D 12 D16,D14 Protects circuit against wrong polarity ofSupply
8 Free pair N11 to N21N12 to N22N13 to N23N14toN24- Works as a loopvia respective junctionbox for flow of current to sensor
11 Diode D21,D22 D23,D24 Protects circuit against reverse polarity
12 Resistor R 31,R32 R33,R34 Limits current to opto-coupler
13 Light emitting diode Green LED.G K11,K12, K13,K14 When glows indicate line is healthy up to DP box A.
14 Opto coupler OPTO OPTO 11 OPTO 12 OPTO 13 OPTO 14 Acts as a loop sensor

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15 Resistor R41.R42R43.R44 Limits the collector current of opto coupler output transistor
16 Resistor R51.R52R53.R54 Limits the base drive current oftransistor T 11 .T12.T13.T14
17 Resistor R61.R62 R63.R64 Limits the collector current ot transistor T 11,T12.T13,T14
19 Light emitting diode LED R L 11.L12 L 13.L14 Glows only when telephone cable theft / cut between respective junction box.
19 Diode D 31 Forms OR gate with other diodes D 32,D 33, D 34 to drive Buzzer
20 Single pole single throw switch SPST Q 11,Q12 Q13,Q14 When OFF mutes the buzzer. When made ON and buzzer works indicates cable theft.
21 R7 Limits the current of the buzzer.
22 Buzzer Buz Givis audio alarm whon oporates
NOTE:1. All the 4 channels are identical
2. The first numerical indicates the respective type component number and
the second number stands for the channel number(For example R11 stands for
resistor number 1 used in channel 1 and so on)
When DPST switch 3 is made ON the LED K in the front of cabinet glows indicated
the 48V power is available to the gadgets.The 48V DO is dropped to requiraqd
vollage by vikkage divider R11, R21 and fed to the control switching circuil. The
system hardware consists of registor transistors.Light emitting Diodes (LED), opto
single pole double throw (SPST),double pole single throw (DPST),fuses F1,F2 are
also used. At the distribution box in the field one free pair is shorted and corrosponding leads at the MDF room is connecred to the input terminats of the
gadgets (N11,N21). This provides a loop for the current to flow for sensing.The DP
boxes are seieored on the basis of circuitry of area to be monitored.For simuiation
the funotionallty of the gadgot. When the switch is made ON(bottom position) other position (top position)shows the actual line is cinnected.As long as cable is
OK the current in the loop flows through D21,R31, K11 and drives opto-coupler

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0PT011 makes green LED K11 ON i.e. cable is in OK condition. Here opto-coupier
acts as a current sensor. Since the collector voltage of OPTO 11 output transistor is around 0.3V it cannot drive transistor T11.Hence during OK condition red LED L11
the opto-coupler do-not get activated, as current is zero, hence green LED K11
supply voltage drives transistor T-11 into saturation making red LED, L 11 to glow. is a cable cut, in this case between junction box 1(A) and junction 2(MDF) and
As soon as the line is restored the SFST switch Q11 is to be made ON, again else
one buzzer is used for not OK condition for all 4 channel using diode D31, as one
clement of OR gates, shown in Fig 3.This is an explanation for how channel 1 functions For other channels similar explanation holds good as all channel contains identical hardware.
The current flowing to the opto-couple loop can be determined from ohm’s law and kept with in the value of minimum and maximum limit of opto coupler input current, for satisfactory operation through resister R 31. As long as the required amount loop current flows in the opto-coupler the gadget indicates the line is healthy, is known from green LED, K11 glowing when no current flows due to cut in cable, glow of red LED L11 speaks cable is cut/theft. At a time glow of green LED, K11 and red LED, L11 is not possible because operation of one is reverse the other. Diode D, D11, D21 are used for protection of circuit against reverse connection power supply by mistake. Fuse F1, F2 protects exchange power supply against dead short in the gadget.
One free pair from each junction box A, B, C, and E are shortened individually and corresponding pair at MDF point are connected to the gadget input terminal N11 N21, N12 N22 N13 N23,and N14,N24 respectively. When the power is made

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ON (48V DC) by DPST switch S, under normal condition green LED K11, K12, K13, K14 glows for junction box A, B, C and E respectively, telling the cable upto junction box A, B, C and E are OK (Fig. 1).
Case -1: Let the cable is cut at the location M (Fig. 1), the green LED K11,K12,K14 glows and the glow of Green LED, K13 disappears and red LED, L13 glows which is
meant for junction box C giving audio alarm, indicating that there is a cable cut in between B and C junction box (last green LED, K12 and first red LED, L13 of the same cable line i.e. cable for junction box C is drawn from junction box B and the free pair is drawn from junction box C to MDF is cut at location M). Since the location of junction box B and junction C is known the lineman can straight go to B-C zone, to locate cut, instead of going to other zones. This saves lots of time.
Case-2: Let the cable is cut at location P. Here green LED K11 and K14 glows respectively for junction box A and E, telling cable up to junction box A and E are OK. Whereas the red LED L12 and L13 glows for respective junction boxes B and C, with alarm. The cable for junction box C is drawn from junction box B and cable pair for junction box. Band C comes from junction box A. Since both the red LED’s are meant for junction boxes B and C are glowing, one has to conclude that there is a cut between last green LED and first red LED in that cable line i.e. between junction box A and B (because both the free pair from junction B and C to MDF room got damaged at the cable location P). Since the location of A,B, C and E are known the lineman can easily find the fault between A and B.
Self testing of the gadget can be done easily. Refer to Fig. 3,when the switch S is closed gadget gets 48V power, is indicated from the glow of LED K. During self test SPDT switch P 11 is closed to point N 21(line N11 open) the current flows through D21,D31,K11,OPTO 11. The glow of green LED K11 tells the device is OK, which is nothing but the simulated condition as if current flows through the telephone line in DP box A. If red LED L 11 glows, this indicates any one all components i.e. operation P 11 always closes to point N 11 and not N 21.

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Limitation of the device
Our device explained here, is not suitable for co-axial cable and optical fiber telephone cable, as their construction and working principles are different than that of multi pair copper telephone cable, Generally the co-axial cable and optical fiber cables are used for connection between to exchanges located far away. As on today all telephone exchange, uses multi pair copper telephone cable for providing telephone connection to the individual subscribers.
It will be appreciated that the principles of the invention as described herein can be applied in many way of which the circuit of FIG.3 and the distribution system of FIG.1 are but examples. Also, in the exemplary embodiment of telephone line monitor and alarm apparatus hereinbefore described, the circuit implementation illustrated in FIG.3 is based on commonly available discrete are integrated circuit components. In an alternate embodiment of the invention, the principles illustrated in FIG.2 may by implemented through the use of microprocessor-based or application specific integrated circuit (ASIC) building blocks, thereby reducing printed circuit board complexity and improving product reliability. Therefore, as will be apparent to one skilled in the art, other circuit approaches may be used in the present invention while utilizing the concepts embodied herein.
Also, this invention is not limited to those of its modes of employment, embodiments and uses have been explicitly. Rather, it encompasses all changes and modification which may be derived by those skilled in the art and which are within the spirit, scope and extent of the invention as set forth in the following claims,

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We claim:
1. A telephone line monitoring and alarm apparatus for detecting the occurrence
of a disruption or loss of telephone service and signaling an audio-visual
alarm thereof, said apparatus comprising:-
an electrical circuit means for monitoring of the health of the cable and alarm functions,
interface means to effect connection of said apparatus to the telephone line,
housing assembly means to enclose said electrical circuit and interface means,
wherein the device is made modular in nature, additional channels can be added for different zones by simply adding cards,
2. An apparatus as claimed in claim 1, wherein said system is completely
hardware based and no software is involved.
3. An apparatus as claimed in claim 2, wherein the said system draws power
from the inbuilt source of the telephone lines from the exchange and no extra
power source is needed.
4. An apparatus as claimed in claim 2, wherein the said system comprises of
different colored LED's for the visual alarm and the audio alarm is optional.
5. An apparatus as claimed in claim 2, wherein no additional manpower is
needed for the operation of the said system.

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6. An apparatus as claimed in claim 2, wherein the system comprises of a self
checking facility for the health of the gadget components, without removing
the gadget from service and the facility can be made optional.
7. An apparatus as claimed in claim 1, wherein the electronic circuit can be used
as continuity tester
8. A telephone line monitoring and alarm apparatus for detecting the occurrence
of a disruption or loss of telephone service and signaling an audio-visual
alarm thereof, substantially as herein described with particular reference to
accompanying drawings
Dated this 15 day of May, 2006

To,
The Controller of Patents,
The Patent Office, Kolkata.