Abstract:
A telephone line protection device which effectively blocks power surge conditions caused by crossed power lines, peripheral lightening strikes, or other types of severe power surges from damaging telephone equipment and computer modems within a home or business.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority from U.S. provisional application 60/216,654, filed Jul. 7, 2000, the entire contents of which are incorporated herein by reference. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    Electronic equipment and particularly computers, computer modems, electrical circuit boards, and telephones are susceptible to damage resulting from exposure to power surges. Power surges, such as those exceeding 375 volts, may be caused by power lines being crossed, by lightening strikes which may damage nearby electronic circuitry and by other causes as well. In the past, attempts have been made to provide power surge limiting devices proximate to electronic equipment to minimize risk of damage during exposure to severe over-voltage situations. Further, in the past, power surge limiting devices have usually been located or positioned proximate to the telephone or modem and rely on the integrity of the ground wire upstream, proximate to the electrical service entrance.  
           [0003]    Ground wires and other grounding means may have or may include variations in impedance. The variations in impedance, in addition to missing components such as ground screws, during power surge conditions, may result in a power surge current pursuing alternative current ground paths through computer mother boards or circuit boards. This may cause damage to the computer mother boards and/or circuit boards. As such, a need exists for power surge protection proximate to the entrance of telephone and/or power lines, and earth ground points to prevent power surge currents from entering phone lines and/or ground wiring within a structure.  
           [0004]    The entire content of all of the patents listed within the present patent application are incorporated herein by reference.  
         BRIEF SUMMARY OF THE INVENTION  
         [0005]    The phone/modem blocker effectively blocks power surge conditions caused by crossed power lines, peripheral lightening strikes, or other types of severe power surges from damaging telephone equipment and computer modems within a home or business.  
           [0006]    In at least one embodiment of the invention, the phone/modem blocker provides an operational verification system which indicates line status of a phone line through the use of an indicator, such as a light, which may be activated or tested by the depression of a test switch. Depression of the test switch in turn causes closure of the test circuit to illuminate the test light which in turn signals the absence of a fault or malfunction.  
           [0007]    The phone/modem blocker may be positioned proximate to, and may be preferably mounted to an electrical distribution panel providing a firm electrical ground for the phone/modem blocker. One or more incoming phone lines may be received by the phone/modem blocker by one or more incoming phone jacks. The phone/modem blocker may also have one or more output or outgoing jacks for connecting to communication devices such as one or more phones, modem, computers, or other devices.  
           [0008]    In at least one embodiment of the invention, the phone/modem blocker utilizes a solid state over voltage protector component or crowbar device such as may be described in U.S. Pat. Nos. 4,685,120, 4,827,497, 4,905,119, 5,479,031 and U.S. Pat. No. 5,516,705 among others. When voltage exceeding the break-over voltage is applied to a over voltage protector component such as a crowbar device, the crowbar device switches from a high off-state impedance to a low on-state impedance creating a short across tip and ring until the current is interrupted or drops below the holding current at which time the crowbar will reset.  
           [0009]    In a preferred embodiment of the invention the crowbar device is a Sidactor® device available from Teccor Electronics, Inc. (formerly ECC Electronics Corp.), of Irving, Tex. In the event of a severe power surge, the present invention isolates each telephone line with a protector component, such as a Sidactor®, and fuse configuration to instantly suppress the surge. The protector component immediately reduces the high voltage spike to zero to prevent damage to the connected electrical modems, circuits or other devices. The fuse also insures the protection of the configuration of the circuit board, modem, and/or circuit.  
           [0010]    In the past, most low cost protection circuits utilized MOV&#39;s in combination with fuses to protect equipment and to isolate phone lines in the event of severe over-voltage exposure from either power line crosses or lightening strikes. In at least one embodiment of the present invention, Sidactors® are used in combination with fuses, as positioned proximate to the electrical distribution panel and earth ground point to isolate and protect phone lines and/or modem lines in the event of severe power surges or over-voltage exposure to prevent damage to electrical components.  
           [0011]    Positioning of a phone/modem blocker of the present invention proximate to the telephone line entrance and earth ground point prevents power-surge currents or excessive power currents from entering the phone line and ground wiring within a building thereby preventing further entry into electronic equipment circuits. The combination of the location for the phone/modem blocker proximate to the phone line entrance and ground point, the use of replacement fuses, the easy test verification indicators, and diagnosis means facilitate maximum usefulness of the phone/modem blocker.  
           [0012]    In at least one embodiment of the invention, the phone/modem blocker may be a fully integrated system utilizing one or more Sidactors®, fuses, a circuit board, indicators such as LED&#39;s, test buttons, and a ground post to effectively prevent excessive currents and/or power surge currents from entering a dwelling and potentially damaging circuitry integral to electronic equipment and/or modems. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0013]    A detailed description of the invention is hereafter described with specific reference being made to the drawings in which:  
         [0014]    [0014]FIG. 1 is an isometric view of an embodiment of the phone/modem blocker;  
         [0015]    [0015]FIG. 2 is an alternative isometric view of an embodiment of the phone/modem blocker having an open cover to display the fuse configuration;  
         [0016]    [0016]FIG. 3 is a circuit diagram of an embodiment of the phone/modem blocker;  
         [0017]    [0017]FIG. 4 is a top down view of a silk screen of the circuit diagram of FIG. 3; and  
         [0018]    [0018]FIG. 5 is an engineering diagram of a circuit board of a phone/modem blocker. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Referring to FIG. 1, an embodiment of the phone/modem blocker is shown general at reference numeral  10 . In general, the phone/modem blocker  10  preferably includes a plurality of phone jacks  12  which are preferably adapted to receive the plug connectors  14  of telephone or modem cables  16 . Of the jacks  12 , at least one jack is an input or line-in jack  13  for receiving the phone line or lines which provide phone service to a dwelling and at least one of the jacks  12  is an out-put or out-going jack  15  for connecting the connector  14  of a phone, modem, computer or other device to the phone/modem blocker  10 .  
         [0020]    The input jack or jacks  13  may be configured for use with any type of phone or modem cable or line. For example, cable  16  may be RJ11, RJ13, RJ45 or any other type of cable for use in connecting telecommunications devices, connector  14  will be respectively configured depending on the type of cable  16  selected. Depending on the type and number of cables  16  configured to come into the blocker  10 , the configuration and number of out-put jacks  13  will proportionally vary. For example it is know that a single RJ11 cable includes four wires  35  (shown in the schematic diagram of FIG. 3). Each pair of wires  35  may form a single line  36  to support a single out-put jack  13 . Therefore, a single RJ11 cable can support one or two out-put jacks. A single RJ13 cable, having  6  wires  35 , may support up to 3 output jacks. A single RJ45 cable, having 8 wires, could provide as many as 4 out-put jacks. It is thus understood by one of ordinary skill that the configuration of the input jack(s)  13  may be made to accept a variety of connector and associated cable types, and that the number and type of out-put jacks  15  may correspondingly varied.  
         [0021]    The phone/modem blocker  10  also preferably includes a plurality of test switches  18  which are in electrical communication with test circuitry for illumination of test indicator lights  20 .  
         [0022]    Preferably the phone/modem blocker  10  is in electrical communication with an electrical distribution panel and earth ground point which is located to the exterior of a dwelling and/or building (not shown) and engaged by a ground wire  46 . An end of the ground wire  46  may be plugged into a ground wire port  45  or otherwise engaged to the blocker  10 . As may be seen in FIG. 3, the electric circuit  26  is in electrical communication with the ground wire  46  thereby ensuring proper electrical grounding of the blocker  10 .  
         [0023]    In operation of the phone/modem blocker  10 , the integrity of the phone and/or modem lines  36  may be identified through the use of the test switches  18 . The depression of the test switches  18  will cause an indicator such as a light emitting diode (LED) or other type of test indicator lights  20  to be illuminated to signal that the fuse  22  (shown in FIG. 2), corresponding to the switch  18  and indicator  20 , is in good operational condition. If the test switch  18  is depressed and the test indicator  20  fails to be illuminated or otherwise triggered, such failure indicates that the fuse is in an open condition necessitating replacement.  
         [0024]    Referring to the embodiment shown in FIG. 2, the fuses  22  are identified as being internal to the phone/modem blocker  10 . Accessibility to the fuses  22  is provided through the use of a retractable cover  24  providing for easy replacement during non-operational conditions. As in the embodiment shown in FIG. 1, each fuse  22  may be tested by activation of a test switch  18  which in turn activates indicator  20  if the fuse  22  is in good operating condition. As evident from FIG. 3, the phone/modem blocker  10  may include four or more fuses  22  at the discretion of an individual. It should be noted that the number of fuses  22  used within the phone/modem blocker  10  may vary significantly dependent upon the number of telephone/modem wires  35  to be protected by the phone/modem blocker  10 .  
         [0025]    In the embodiment depicted in FIGS. 2 and 3, two telephone/modem lines  36  are depicted having 4 shared wires  35 , wherein each wire  35  utilizes four fuses  22 . Each additional telephone and/or modem line  36  utilized within the phone/modem blocker  10  utilizes two additional fuses  22 . Each fuse  22  may have any capacity as desired by an individual and are preferably  35 A, 125 volt glass fuses which may be readily available from an electronics component source.  
         [0026]    Referring to FIG. 3, one embodiment of the electronic circuit  26  used in conjunction with the phone/modem blocker  10  is illustrated. The electrical circuit  26  is illustrated for use in conjunction with four wires  35  which enter the circuit  26  from the input jack  13 . The four wires  35  form two shared telephone/modem lines  36  which are connected to two out-put jacks  15 . It should be noted that the electronic circuit  26  as depicted in FIG. 3 may be altered for use in the protection of a single phone line or for three or more telephone/modem lines  36  at the discretion of an individual. In order to add a phone line  36 , a corresponding additional amount of fuses  22 , Sidactors®  28 , LED&#39;s  30 , and test buttons  18  are utilized. It should be further noted that additional line receiving ports  12  will be required for releasable receiving engagement of each additional telephone/modem line  16 .  
         [0027]    Referring to FIG. 3, fuse  32  and  34  protect the first phone line  36   a . The phone line  36   a  is always connected to the center two terminals  38  of jack  13 . Sidactors®  42 ,  44  and  45 , connect from tip-to-ground  46 , tip-to-ring, and ring-to-ground  46  respectively. Any exposure of electric circuit  26  to voltage over 375 volts will cause Sidactors®  42 ,  44  and  45 , to switch diverting current away from the output jacks  15 .  
         [0028]    Push button/test switch  50 , resistor  52 , and bi-directional indicator such as an LED  54  are preferably connected across phone line  36   a  such that the depressing of the push button test switch  50  will cause the bi-directional LED  54  to illuminate in the event that fuse  32  is in good operational condition and phone line  36  is intact to this point. Push button, test circuit  56 , resistor  58 , and bi-directional LED  60  are connected across a second phone or modem line  36   b  such that the depression of the push button test switch  56  will cause the bi-directional LED light  60  to illuminate only if fuse  34  is in good operational condition and phone line  36   b  is intact to this point. It should be noted that resistors  52  and  58  limit the current to the bi-directional LED&#39;s  54 ,  60  to a reasonable value, driven by the DC voltage provided from the phone service. Phone line  36   b  is preferably connected to the outer terminals  64  of the jack  13 . Sidactors®  68 ,  70 , and  72 , preferably protect line  36   b  through fuses  74 ,  76  respectively. Push button/test switch  78 , resistor  80 , and bi-directional LED  82  are connected across phone line  62  such that the depression of test switch/button  78  will cause the bi-directional LED light  82  to light only if fuse  74  is in good operational condition and phone line  36   b  is intact at this point. Test switch/push button  84 , resistor  86 , and bi-directional LED  88  are connected across phone line  36   b  such that the depression of test switch/push button  84  will cause the bi-directional LED  88  to illuminate only if fuse  76  is in good operational condition and the phone line  36   b  is intact at this point.  
         [0029]    The resistors  52 ,  58 ,  80 , and  86 , are preferably 5.1 k, 1/2 w resistors as may be commonly available from any electrical supplier. The bi-directional LED light sources  54 ,  60 ,  82 , and  88 , are preferably twin LED 3 mm light sources having a red wavelength. The Sidactor&#39;s®  42 ,  44 ,  45 ,  68 ,  70 , and  72 , may be Model No. P3100EB as available from Teccor Electronics, Inc.  
         [0030]    Most lightening damage to electronic circuitry occurs through a telephone line. A lightening strike in the general area of a receptor site is capable of inducing a destructive high voltage spike on the telephone line. It is desirable to provide primary protection blocks to divert the high voltage spikes from reaching the printed circuit boards through an electrical ground. The high voltage surge must be shunted to ground preferably before it enters a building through a telephone wire.  
         [0031]    The Sidactors®  42 ,  44 ,  45 ,  68 ,  70 , and  72 , are preferably the desired switches to provide for an electrical path or shunt to ground within the phone/modem blocker  10 . Alternatively, thyristors and/or triacs may be used in place of the Sidactors® to provide for a desired electrical path or shunt to ground.  
         [0032]    Sidactors®  42 ,  44 ,  45 ,  68 ,  70 , and  72 , are bi-lateral switches, similar to a triac without a gate connection. A Sidactor® may be triggered into conduction regardless of polarity, but only by an over voltage pulse. Sidactors® are often used as over voltage protection devices with clamping voltages from 20 to over 500 volts. Upon application of a voltage exceeding the breakdown voltage, the Sidactor® switches on through a negative or positive resistance region to a low on-stage voltage. Conduction will continue until the current is interrupted or drops below the minimum holding current. The Sidactor® may offer longer life and faster response (nanoseconds) than other types of protection and is able to respond without voltage overshoot. The Sidactor® is preferably as fast as a zener diode, while offering a much lower impedance (leakage current less than 5 μa) during conduction. Preferably the Sidactor® performs at high speeds (high dv/dt) providing optimal triggering to prevent power surge/power current damage to electronic circuitry.  
         [0033]    A triac is an electronic relayer switch which is located either externally or fixed within the controller. A triac operates when it receives an electronic gate signal from the control circuitry. The triac then switches to its closed or on state thus providing a desired voltage path. In this situation, the triac would provide a voltage path to ground to prevent entry of excessive power currents or power surges into a dwelling via a phone line to prevent damage to electronic circuitry.  
         [0034]    A thyristor is generally a solid state semiconductor switch which acts to open a circuit capable of withstanding the rated voltage until the circuit is triggered. Once the circuit is triggered the thyristor becomes a low-impedance current path until either the current stops or falls below the minimum value called the holding current. A thyristor may only conduct current in one direction, much like a rectifier, whereas a triac may conduct current in both directions.  
         [0035]    In FIG. 4 a top down view of the silk screen of an embodiment of a circuit board of the blocker  10  is shown which corresponds to the elements of the circuit diagram of FIG. 3.  
         [0036]    In FIG. 5 an embodiment of a circuit board  100  of the blocker  10  is shown.  
         [0037]    In addition to being directed to the specific combinations of features claimed below, the invention is also directed to embodiments having other combinations of the dependent features claimed below and other combinations of the features described above.  
         [0038]    The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. All these alternatives and variations are intended to be included within the scope of the claims where the term “comprising” means “including, but not limited to”. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.  
         [0039]    Further, the particular features presented in the dependent claims can be combined with each other in other manners within the scope of the invention such that the invention should be recognized as also specifically directed to other embodiments having any other possible combination of the features of the dependent claims. For instance, for purposes of claim publication, any dependent claim which follows should be taken as alternatively written in a multiple dependent form from all prior claims which possess all antecedents referenced in such dependent claim if such multiple dependent format is an accepted format within the jurisdiction (e.g. each claim depending directly from claim  1  should be alternatively taken as depending from all previous claims). In jurisdictions where multiple dependent claim formats are restricted, the following dependent claims should each be also taken as alternatively written in each singly dependent claim format which creates a dependency from a prior antecedent-possessing claim other than the specific claim listed in such dependent claim below (e.g. claim  3  may be taken as alternatively dependent from claim  2 ; claim  5  may be taken as alternatively dependent on claim  3 , claim  6  may be taken as alternatively dependent from claim  3 ; claim  7  may be taken as alternatively dependent from claims  3 ,  5  or  6 ; etc.).