Patent Publication Number: US-7592719-B2

Title: Protection of A/V components

Description:
BACKGROUND OF INVENTION 
     The current invention relations to a wall mounted electrical junction box for power and low voltage signal connections of related electronic components, circuits composed therein and methods of using the same. 
     Electronic components used in audiovisual systems are subject to damage from electrical power surges. Numerous technologies and designs exist for either disconnecting equipment from such damaging conditions, or shunting the power to a ground connection via a nonlinear component. However, effective implementation of the schemes and designs requires interconnected components to be connected with a single ground source. 
     Moreover, typical audiovisual systems utilize multiple powered components, which are interconnected to receive and transmit relatively low voltage signals. To the extent that some of these components are physically separated from other components, for example, the visual display unit for a home theater system might be located across the room from a cabinet containing the DVD player or high-definition television encoder, low voltage signal wire cabling is preferably routed through walls to avoid physical hazards, as well as a cluttered appearance. 
     Although power and signal cables might be physically separated outside of the interconnected components, over voltage conditions, arising from unstable line voltage, or lightning strikes, can propagate through multiple components in the absence of an appropriately designed system. Accordingly, there exists a need for connection devices that can facilitate the installation of multiple, physically separated audiovisual components in a manner that readily provides necessary surge protection. 
     There exists a further need for connection devices that can be readily installed in walls and accommodate a wide variety of low voltage signal connectors as might be encountered when combining various types of displays, video processors, audio equipment, data communication equipment and/or computers. 
     There remains a further need for such connection devices that permit various audiovisual components to be mounted nearly flush to the structural walls or other architectural features, yet at the same time accommodate a variety of connector plugs and socket styles. 
     SUMMARY OF INVENTION 
     The above and other objectives of the invention are satisfied in a first aspect by providing a connection box for wall installation that has a front face that covers substantially all of a cut-out in the wall. Within the front face is a first cavity extending inward to receive a power cord plug at a socket disposed at the bottom of the cavity, for example, a power plug connector having line (L), neutral (N) and ground (G) terminals. The corresponding socket has input terminals for L, N and G disposed behind the socket. The box also includes an aperture for receiving at least one of a blanking plate &amp; a signal connection module, two or more walls disposed on opposing sides of the aperture and extending inward faces. The inwardly extending walls are in contact to form an electrical contact with at least one of the ground input or output terminal of the socket. Thus, power plugs can be recessed into the connection box, via the aperture, permitting a nearly flush mounting of the associated A/V components. 
     In a second aspect of the invention, a signal connection module or blanking plate is inserted into the aperture cover the remainder of the aperture, avoiding an opening between the wall interior and the room. The module or blanking plate is supported by the walls on opposing sides of the apertures. 
     The above and other objectives of the invention is satisfied in a first aspect by providing power to the electronic components of the Audio/Visual system power from a single power conditioning module, the power conditioning module having an input connection in which phase, neural and ground wires are connected to the power mains circuit. Physically adjacent A/V components, which may or may not include a display, are connected to the output terminals of the power conditioning module to receive filtered power there from. 
     Physically remote A/V components are connected to the power-conditioning module via a pair of connection boxes that accommodates a power receptacles and low voltage signal receptacle. The first connection box is located proximal to the power-conditioning module and A/V components. The second connection box is located proximal to the physically remote equipment. The display is energized via connection to the output receptacles of the remote connection receptacle and receives at least one of an audio or visual signal via connection to the signal output socket of the remote connection receptacle. Accordingly, the display and signal generator share a common conditioned power source from the power conditioning module, and the remote connection receptacle provides a common ground connection between the signal generator, the display unit and the power-conditioning module. 
     In another aspect of the invention, the signal connection module is dimensioned for insertion into the aperture within the front face of the aforementioned connection box. Accordingly, the signal connection module has a substantially flush front face with one or more sockets for receiving corresponding signal plugs from the associated A/V equipment. The signal module also has at least two adjacent sides connected to the front face of the module that fit closely between corresponding walls extending inward from the aperture in the connection box. Low voltage signal output connectors emerging rearward from behind the front face correspond to the multiple low voltage signals input sockets disposed on front face of the module. Two or more opposing sides of the module are in electrical connection with ground shield wires associated with the low voltage signal wires that connect the input and output connectors in the module, providing electrical continuity to a common ground associated with the power socket ground wire (via physical contact with the wall associated with the aperture in the connection box.) Electrical continuity is maintained over a range of alternative positions of the signal module within the connection box aperture, thus both the signal and power plugs can be recessed into the connection box, permitting a nearly flush mounting of the associated A/V component with respect to the walls of the room. 
     As will be further described, other aspects of the invention include mechanical features for grasping, moving and latching the signal module at variable position rearward from the front face of the connection box, as well as connection boxes configured to receive an array of signal connection modules, with or without blanking plates. Thus the inventive connection box and device accepts various low voltage signal modules for rapid installation and reconfiguration. Further the box and device creates an isolated ground reference for all signal modules, with a common surge protection circuit. In additional, the preferred embodiment of the signal protection circuit uses fewer, and lower cost components that the prior art devices. 
     The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an exploded perspective view showing the connection box and signal connection module. 
         FIG. 2  is a first schematic electric circuit for the connection box and signal connection module. 
         FIG. 3A  is an elevation of the connection box taken through the wall bisecting the signal connection module; whereas  FIG. 3B  is an exterior elevation as observed from the room. 
         FIG. 4  is an elevation of an alternative embodiment of the connection box including an installed signal module as observed from the room. 
         FIG. 5  is a second schematic electric circuit for the connection box and signal connection module. 
         FIG. 6  is a third schematic electric circuit for the connection box and signal connection module. 
         FIG. 7  is a schematic electrical circuit for the interconnection of A/V equipment to a common power conditioning module as the power supply, utilizing a connection box, having the circuit of  FIG. 2 , adjacent to the power conditioning module. 
         FIG. 8  is a schematic electrical circuit for the interconnection of A/V equipment wherein only the signal processing module(s) are connected to the power-conditioning module, and the display unit is independently connected to the breaker panel as the power source. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates in an exploded perspective view of the connection box  100  and signal connection module  150  for use therewith. Connection box  100  has a front face  110  for mounting substantially flush with a surface, generally a room interior wall. Although signal connection module  150  is normally inserted into the connection box  100  from the front face  110  side of connection box  100 , it is shown behind the front face  110  for illustration purposes. Connection box  100  has a first cavity  120  that extends inward, that is, toward the interior of the wall, from the front face  110  for receiving a power connector in socket  130  disposed at the bottom of the cavity  120 . Accordingly, socket  130  has electrically isolated input sockets for receiving plug prongs for connecting the corresponding line, neutral and ground wires thereto. Although not shown in this Figure, it should be understood that connection box  100  also includes corresponding line, neutral and ground connection terminals for receiving bare conductor wire mounted behind the socket  130 . The aforementioned components are however illustrated in the schematic electrical circuit diagram of  FIG. 2 . The front face  110  of connection box  100  also includes at least one aperture  140  for receiving either a blanking plate  105  (shown in  FIG. 4 ) or a signal connection module  150 . Signal connection module  150  is inserted into aperture  140  and thus supported by two or more sidewalls,  145   a  and  145   a ′ that are disposed on opposing sides of the aperture  140  to extend inward from the front face  110 . In this embodiment, two additional side walls  145   b  and  145   b ′ connect with walls  145   a  and  145   a ′ to form a box like enclosure. Further details of the construction and operation of the signal module  150  are described below and in particular with reference to  FIGS. 2 ,  3  and  4 . 
     It should be appreciated that power socket  130  is optionally selected to receive either a straight prong connector plug, as illustrated, or a twist lock plug, but can be any plug type, particularly when it is desired to limit the connection to a single electronic component with a mating power cord connector, such as a power conditioning module. Connection box  100  also has a plurality of holes at the periphery of face  110  that are disposed to align with a convention terminal box, or J-Box, located behind the wall, the terminal box being generally required by electrical and building codes. Thus, screws inserted in these holes physically secure connection box  100  with respect to the wall or other planar mounting surface. In the most preferred embodiment, connection box  100  extends like a flange about the periphery of the front face  110 . Such a flange extension conceals the J-box, but is more preferably limited in outer dimensions for receiving a decorative cover plate. Thus, outer or peripheral dimensions of front face  110  are slightly smaller than a conventional decorative wall plate, should a user or consumer wish to cover a portion of face  110  for aesthetic reasons. 
     As will be further described with reference to  FIGS. 2 ,  3  and  4 , at least one of the sidewalls  145   a / 145   a ′ and  145   b / 145   b ′ of connection box  100  contact and provide electrical continuity to the ground input and output terminals or junctions of signal connection module  150 . 
     Signal connection module  150  has a front face  160  and at least two opposing sides  165   a  and  165   a ′ parallel to each other and disposed perpendicular to the front face  160 . Multiple low voltage signal input sockets  170   a, b, c, d  and  e  are also disposed on front face  160 . Corresponding multiple low voltage signal output connectors  180   a, b, c, d  and  e  emerge rearward from behind the front face  160  having separate parallel electrical connections corresponding to input sockets  170   a - e . Further, in this preferred embodiment shown, output connectors  180   a - e  are separated from the rearward portion of signal connection module  150  by lengths of signal wire cables  181   a  to  181   e . The signal wire cables extend output connectors  180   a - e  away from signal connection module  150  to enable the convenient installation of signal wire from the room after connection box  100  is installed. That is, signal connection module  150  can be inserted from the room side of connection box  150 . Accordingly, it should be appreciated that the signal connection module is readily reconfigured after an initial installation, should the user or consumer wish to deploy alternative A/V sources. The signal cables  181   a  to  181   e  provide slack, and hence effective strain release, for cable running behind the wall when the signal connection module is installed or reconfigured. Further, the signal wire cables  181   a  to  181   e  enable the use of larger output sockets that might not fit on the front face  160  of signal connection module  150 , but would still fit in the space behind or within the wall. 
     Further, as is more fully described with respect to  FIG. 3 , additional mating components associated with the sides of signal connection module  150  and connection box  100  permit signal connection module  150  to be offset at multiple positions within aperture  140 . Such features include a spring-loaded ball  166 , which is mounted within signal connection module  150  and extends partially through a hole in the upper surface  165   a  of connection module  150 . As the associated spring urges ball  166  into the hole and a corresponding orifice ( 351 ,  352 ,  353 ) on the opposing face of the aperture wall  145   a , the signal connection module  150  is secured in aperture  140 , but still readily removable by the application of sufficient lateral force to overcome the retaining force of the associated spring. Accordingly, on moving the signal connection module  150  laterally within aperture  140 , ball  166  is displaced back into the signal module  150 , out of contact with the opposing face of the aperture wall  145   a . Thus, the placement of multiple mating orifices  351 - 353  on the opposing face permits the variable adjustment of the recess of the front face  160  of signal module  150  behind the face  110  of connection box  100 , as shown in  FIG. 3  and  FIG. 4 , below. Referring to the schematic electrical circuit of  FIG. 2 , it should be apparent that the front face  160  of signal connection module  150  and its opposing (rear) side make electrical contact connection with ground shield wires associated with 2 or more of the signal input and output connectors  170 ,  180 , which can be plugs or sockets. Thus, at least one of the sidewalls  165   a/a ′ or  165   b/b ′ makes electrical contact with one of walls  145   a/a ′ or  145   b/b ′ associated with the aperture  140  in connection box  100 , thereby providing a common ground connection between the circuit sub modules in the Figure. However, it should be further appreciated that the electrical continuity between the respective ground wires in the signal module and the connection box is insured by the springs urging ball  166  into contact with both the signal module and the connection box components. 
     In a more preferred embodiment, at least one of the sides  165   b  of signal connection module  150  has a recessed flat panel,  165   c , for receiving a label displaying printed matter, such as product identification, installation instructions and the like. Placing the printed labels within recessed panel  165   c  avoids the wear or degradation of the label on the otherwise contacting face of the side wall  145   b  of aperture  140  in connection box  100 . 
     The front face  160  of signal connection module  150  optionally includes any variety and combination of input sockets and output sockets or output plugs, such as RCA, VGA, Co-axial cable, phone, data communications, Ethernet type, and the like. It should be further appreciated that extension cables  181   a - e  can be of any length, or alternatively eliminated depending on the need for the optional adjustability of signal connection module  150  within aperture  140 , the skill of the installer, or the intended permanence of the installation. 
     The electrical schematics of circuit  200  in  FIG. 2  further illustrates other aspects of the invention wherein optional signal protection, power protection (collectively SP) or power conditioning components are interconnected via a common ground connection between the signal over-voltage protection circuit module  230  and the ground wire of socket  130  of the power circuit module  210 . It should be appreciated that the actual circuit protective function in power circuit module  210  and signal over-voltage protection circuit module  230  is accomplished by limiting voltage differences between wires passing to the protected A/V equipment (PE) to levels safe for the equipment. If the allowable voltage difference between two terminals of the equipment is exceeded, either an insulating path isolating the connections will flash over, or a component connecting the two terminals will overheat and be damaged. Since both the number of terminal connections and the allowable voltage differences vary widely from one piece of equipment to another, surge protectors must be specially designed to meet the needs of the PE. Broadly, the connections to PE can be defined as being either “Power” (e.g.,  120  VAC in many cases), or “signal” connections. Power connections provide for the power supplies for the PE, as well as powering AC-powered equipment such as monitors and displays, as well as DVD players, amplifiers and the like. Signal connections are generally of lower voltage and current than power connections, and are used to transmit information and control among different pieces of the PE. Typically, but not always, the AC connections will withstand larger voltages than the signal connections. 
     Four components that are relatively uncommon are found in surge and overvoltage protection circuits. The four components are non-linear voltage dependent devices, and can be Gas Tubes (GT), diodes (D), sidactors (Q), bi-directional transorbs, Cr) and metal oxide varistors (MOV). These components are normally insulating in the normal state of the devices operation, but become highly conductive in response to a voltage surge. Accordingly, they are connected in parallel to protect circuits from over voltage by providing an alternative path for current flow. Gas Tubes (GT) are spark-gap breakdown devices, which typically have voltage breakdown levels of 90-1000V. Below the breakdown level, they are totally non-conducting. Once they are broken down, the voltage across them falls to ˜30V even for very large currents. They are very inexpensive and have high surge absorbing capacity. Even small tubes (circa 8 mm diameter×6 mm long) can conduct short (20 microsecond) current impulses up to 10,000 A. 
     It should be appreciated that the exemplary protection circuit shown in  FIG. 2  is not intended as a limiting example, as in alternative embodiments further surge protection circuitry is optionally provided on an adjacent PCB behind the power socket  130 , being operative to shunt current from high voltage transients in the power lines to the common ground connection. In other selected embodiments, a noise filtering circuit is optionally provided on an adjacent PCB behind the power socket  130 . 
     The “Q” components are sidactors, a silicon solid-state analog of the gas tube. Sidactors are non-conductive until a breakdown voltage (typically 30V-1000V) is reached, and then they become highly conductive, with a typical saturation voltage of 3-5V while conducting. Q components, being latching devices, after “tripping” require a voltage reduction below a specific threshold before they unclamp, and become resistive again. The Q devices used in embodiments described in  FIGS. 2 ,  5  and  6  have a 5-15 volt breakdown level. Accordingly, these exemplary circuits accommodate a wide range of low voltage switching modules not likely to have a separate ground. Both the GT and the Q devices are difficult to use in power circuits, because once they have broken down, they form effectively a dead short across the terminals, and take the entire available current of the supply, until (if the circuit is AC) the applied voltage goes to 0, and they turn off. That is a major reason that AC protectors generally use varistors. 
     Additional surge protection components including zener diodes (D) and the closely related transorbs are widely used in SP circuits. 
     The MOV components (metal-oxide varistors) are ceramic semiconductor devices widely used for AC power protection. They typically have limiting voltages from 30V to 1000V. MOVs are not breakdown devices, but voltage limiters similar to zener diodes or transorbs. They start to conduct above a certain voltage. The MOV devices used here in the AC or power circuit preferably limit the incoming voltages to about at 430V. 
     Additional components, shown in the circuit diagrams in  FIGS. 5 and 6 , that perform auxiliary functions include thermal fuses (TC) and fuse traces (FT) to protect against sustained and impulse AC overvoltage. The GTs themselves are not inherently necessary in the operation of these circuits under most conditions, but provide extra protection in the case of very high-current surges (e.g., &gt;500 A) that might occur under direct lightning strike conditions. An example of such an event would be if lightning struck directly an antenna or satellite signal receiving dish. For components inside a building, the GTs would not normally be used; they are described for completeness only. Each thermal cutoff fuse is placed as near as possible a metal oxide varistor such that in sustained high voltage conditions, if the overvoltage heats and then permanently damages the metal oxide varistor, the associated thermal cutoff fuse is activated to open the circuit leading to both the MOV and the protected equipment, thus disconnecting the excess voltage. 
     It is also desirable to include one or more sub circuits that indicate if the protector receives power from the wall, or has been damaged or tripped, and is thus not operative even if receiving AC power from a wall socket. Those of ordinary skill in the art can appreciate that a light emitting diode, LED, will function as such an indicator when disposed between the line and neutral and circuit in series with the appropriate resistor and diode to indicate to the user that the wall socket connection is powered. It will be further appreciated by one of ordinary skill in the art that signal protection sub circuit modules may also include additional circuit components that comprise the light emitting diode to indicate when the output socket is no longer powered, such as when one or more of the thermal cutoff fuses has tripped. 
     The “P” component, or the fifth type of component, is not voltage sensitive per se, like the other components, but has a positive-temperature-coefficient resistance (PTCR), and acts as a resistor (typically a few ohms) at low temperatures. The preferred PTCR component is particularly non-linear in resistance at a specific temperature threshold, reached by joule heating from carrying current, with the resistance increasing by as much as 1 million times, effectively opening the circuit, to protect the PE. 
     Thus, in  FIG. 2 , the separate socket terminals on the face power plug socket  130 , denoted as line voltage (L)  241 , Ground (G)  242  and neutral (N)  243 , are connected by wires  211 ,  212  and  213  to respective rear connection terminals  221 ,  222 , and  223 . The rear connection terminals are for securing conventional interior power wiring, per local electrical and building codes. Ground wire  213  is represented as connected to a common ground to emphasize the electrical continuity between the signal connection module and connection box, shown as circuit trace  250 . 
     The pair of input connectors shown in this diagram,  270   a  and  270   b , comprises an outer conductor, usually connected to signal ground, which provides a signal path to respective output terminals  180   a  and  180   b  over signal wires  271   a  and  272   a . Central socket conductors of sockets  170   a  and  170   b  connect to the center pins of output terminals  180   a  and  180   b  via signal wires  271   b  and  272   b.    
     The signal connection module  150  preferably has an over-voltage protection circuit  230 , which is disposed in serial connection along each of the signal paths  270   a  and  270   b  connecting the isolated input and output (I/O) terminals or junctions  170 / 180   a - b . Note that additional I/O terminals, such as those described with respect to  FIG. 1 , are omitted merely to simplify the diagram, the number and type in each Figure being exemplary and not intended to limit the scope of the invention. 
     Signal wire lines  271   a/b  and  272   a/b  are in fact preferably formed on a printed circuit board (PCB) to facilitate interconnection with the protection circuitry. Thus, each individual signal wire in the over-voltage protection circuit  230  is in a parallel connection with a protected path to ground trace  250  via a first pair of isolating diodes. Signal wire  272   b  is isolated from both a voltage limiting device  261  and rectifier diode  260   b , which leads to ground, by diode pair  265   a  and  265   b . Signal wire  272   b  connects to the cathode of diode  265   b , which then connects to the cathode of voltage limiting device  261 . The anode of diode  265   b  also connects to the anode of rectifier diode  260   b , limiting current flow to the clockwise direction in the loop connecting diodes  260   a ,  260   b  and voltage limiting device  261 . Signal wire  272   b  also has a parallel connection to the anode of diode  265   a , the cathode of which connects to the cathode of voltage limiting device  261  as well to the cathode of rectifier diode  260   a . Signal wire  272   a  is similarly isolated from voltage limiting device  261 , rectifier diode  260   a  and rectifier diode  260   b  by diode pair  264   a  and  264   b , and likewise for signal wire  271   b  (via diode pair  263   a/b ) and signal wire  271   a  (via diode pair  262   a/b .) Thus, the diode pairs limit any excess current from the signal wires to flow clockwise to device  261 , which acts in the reverse bias condition to set the protecting or clamp voltage for the protected A/V equipment. Thus, in this preferred embodiment rectifier diodes  260   a  and  260   b  direct current that is shunted from the signal lines upon an over voltage condition, as defined by the voltage threshold of the device  261 , such that the shunted current will flow in the clockwise direction to trace  250  and then to ground. Voltage limiting device  261  is preferably a silicon avalanche diode (SAD)  261  that also isolates the signal circuit conductive traces  270   a  and  270   b  from high currents that could otherwise be conducted through rectifier diode  260   a , such as upon high voltage surges occurring within power circuit module  210 . 
       FIG. 3  illustrates further the mechanical features of a preferred embodiment of the invention, shown in elevation taken through an installed signal connection module taken orthogonal to the wall (represented by segments  390  and  390 ′ above and below the signal connection box respectively). Connection box aperture wall  145   a  has indentation(s) for receiving a mating feature disposed on the sidewalls of the signal module  150 . Note that in this embodiment, signal connection module  150 , while slideable within aperture  140 , is disposed at the intermediate of three positions, being removeably secured by the displacement of ball  166  into the second of three hemispherical depressions  351 ,  352 ,  353  that extend upward into wall  145   a  of aperture  140 . Thus, the placement of the hemispherical depressions  351 ,  352 ,  353  defines a plurality of latched positions for signal module  150  within aperture  140 . A spring  368  is fixed at one end to a portion of connection module  150  with the opposing end extending upward to urge ball  166  out of a circular hole formed in the upper surface  165   a  of signal connection module  150 . Accordingly, on pulling or pushing module  150  in the lateral direction the force of spring  368  is overcome such that ball  166  can then engage in either of the adjacent hemispheres,  353  and  351 , securing the signal connection module in an alternative position. As ball  166  is spring loaded, it provides for a secure electrical connection from connection box  100  to signal module  150 . The spring  368  is preferably supported within the bore of a threaded shaft  367 , the shaft bottom being either closed, or having a diameter smaller than the diameter of spring  368 . The threaded shaft  367  is then inserted into a nut or other component with mating thread on the inside of wall  165   a  below the hole that limits the spring-loaded ball from extending therethrough. It should be appreciated that alternative embodiments to a latching function supplied by the spring-loaded ball  166  include other types of spring members, possibly without a ball, but direct spring contact. Further embodiments that perform substantially the same function include, without limitation, plural mating features on each signal connection module, such as holes or hemispherical depressions, with a spring-loaded ball or hemisphere extending from the aperture sidewall. In this alternative embodiment, the ball or hemisphere would retract into the aperture walls of the signal connection module (or blanking plate) on translating the same within aperture  140  of connection box  100 . 
     Further, the ball  166  and mating features in aperture wall  145   a  or  145   b  are preferably offset to one side of the center line of signal connection module  150  to provide maximum space for signal connection sockets centered on the front face  160  of signal connection module  150 , thus maximizing the available space for a PC board  380  and associated surge protection components. 
       FIG. 3  also illustrates one embodiment of a mechanical feature suitable for grasping and either sliding or removing the signal connection module  150  from the room side. A grip-receiving member  377  is preferably formed by providing an adjacent pair of slits to define a narrow strip of metal. The narrow strip of metal is then deformed outward from face  160  to form grip-receiving member  377 , essentially an isthmus that extends several millimeters outward to the room side. Accordingly, a gripping tool can be inserted at the slit edges to reach behind and grasp member  377  from the room side of the connection box. It should be appreciated that grip receiving member  377  is alternatively formed as an inward protruding indentation formed about slits in the front face. In the latter embodiment, the gap between the slits when punched in forms an isthmus to provide access to insert an alternative tool behind the back of the front face to grasp the signal connection module  150 . In either case, a preferred form of tool is essentially a plier with suitably dimensioned tips to grasp one or more of grip receiving members  377  and retract the signal connection module  150  back into the room. Further, a pair of grip receiving members  377  and  377 ′ are preferably disposed offset from the centerline of signal connection module  150  such that they do not interfere with the placement of signal sockets on the front face, or a printed circuit board (PCB)  380  mounted within the signal connection module. Further, the connection box  150  preferably includes one or more backstops  168  that extend laterally at the rearward end of apertures walls  145   a/a ′ or  145   b/b ′ and thus preclude signal connection module  150  from accidentally being pushed through aperture  140  and falling behind the wall  390 ,  390 ′. 
     In addition, a sequence of hemispherical depressions akin to  351 ,  352  and  353  are preferably disposed at equal offsets from the vertical center line through aperture  140 , on the bottom wall  145   a ′, but omitted for clarity, for removable engagement of an additional spring loaded ball (also omitted for clarity) disposed at the bottom surface  165   a ′ of signal connection module  150 . 
       FIG. 4  further illustrates the mechanical features of an alternative embodiment of the invention. Multiple signal modules and blanking plates are illustrated in an elevation of connection box  400  as viewed from the room side. Thus, connection box  400  has a wider aperture  440  than aperture  140  in  FIG. 1 , to accommodate three signal connection modules. In this Figure, signal connection modules  450  and  451  are disposed on opposing sides of blanking plate  440 . Each of the signal modules  450 ,  451  and the blanking plate  440  has one or more substantially identical grip members  377  disposed on their front face. Further, each of signal connection modules  451  and  450  deploy distinctly different types and combinations of low voltage signal sockets. That is, signal connection module  451  includes a substantially rectangular multi-pin connector terminal  470   a  and a round connector terminal  471   a . It should be appreciated that a multi-pin connector optionally replaces any round connector illustrated. Further, any of the output terminals on the rear side of the signal connection module  150 , such as  180   a - e  in  FIG. 1 , are optionally configured as male or female connections, screw or spring loaded terminals for receiving bare conductor or insulation displacement style terminals, and the like. 
     Also illustrated in further detail in  FIG. 4 , a blanking plate  440  has the same exterior dimensions as signal connection modules  450  and  451 , with a substantially planar front face, and a ball or other latching member to provide the same adjustable function as ball  166  on signal connection module  150 . Blanking plate  440  need not include additional side faces, provided that a top face and a corresponding face at the bottom of blanking plate  440 , or other mechanical features, provide sufficient structural rigidity. Similarly, in the signal connection module  150  side faces  165   b  and opposing side face  165   b ′ (not shown) are also optional, being provided to house and protect electrical component and terminal within signal connection module  150 . 
       FIG. 5  illustrates another embodiment of a circuit  500  within a signal connection box in which the power circuit module  505  includes further electronic components to filter the AC power before it reaches the A/V device. Thus, the circuit in  FIG. 5  removes AC ripples and other noise induced or picked up by a cable segment connected to a power-conditioning module as described below with respect to  FIG. 7 . Within power circuit module  505  a pair of 0.47 microfarad capacitors  510  and  520  are disposed in parallel between the line  211  and neutral  212  wires. The circuit  500  utilizes the same over-voltage protection circuit  230  as previously described with respect to  FIG. 2 . The components in power circuit module  505  are preferably supplied on a printed circuit board. 
       FIG. 6  illustrates another embodiment for deployment within a connection box or receptacle, in which circuit  600  now includes a power circuit module  605  configured with power line surge protection providing a parallel connect to ground, in the occurrence of a power surge, for the L, N and G lines of the power socket. A first MOV  610  is interposed between line (L)  211  wire and the neutral (N)  212  wire, a second MOV  620  is interposed between line (L)  211  wire and ground (G)  213  wire, with a third MOV  630  being interposed between the N  212  wire and the G  213  wire, forming a delta circuit among L, N and G. For AC or peak voltages below 430V, the MOVs are almost completely nonconductive. However, when the voltage across the input connections goes above a threshold, preferably about 430V, the MOVs conduct, thus generally limiting the voltage at the rear connection terminals  221 ,  222 , and  223 , to what is commonly described as a clamp voltage. The clamp voltage experienced by the protected equipment depends on the resistive characteristics of the MOV at the surge voltage above the threshold, and the MOV capacity for handling power without breakdown. IEEE descriptions (IEEE Standard 062.41-1991, at p. 31) of the “surge environment” indicate that voltage surges as large as 6 kV, with corresponding current surges up to 3,000 A could be produced L-N or L-G, at a residential receptacle, by nearby lightning. From manufacturer&#39;s characteristics for the MOVs used, the protector should limit the 6 kV impulse to 800-900V. There is data, published in Power Quality, K. B. Bowes, 1990, pp 296-310, suggesting that AC appliances are robust against short impulses, applied to the AC terminals, of up to 1000V. So the AC surge protection is provided by the L-N and L-G MOVs. The N-G MOV is not normally active in this situation, but might be important, if, for example, the receptacle that provided the power were L-N reverse-wired. A thermal fuse  606  in line wire  211  provides protection to the multiple MOV&#39;s in circuit  600  from a sustained high voltage condition. 
       FIG. 7  is a schematic electrical circuit  700  for the interconnection of A/V equipment to a common power-conditioning module  714  as the power supply. The A/V components  702  optionally generate signals from media, or receive them externally, for example from a telephone transmission line via a modem or DSL signal via wire or cable  733 , cable TV via wire or cable  732 , or via a satellite receiver on wire or cable  731 . The connection box  7200  adjacent to power-conditioning module  714  and signal generating A/V components  702  preferably has the mechanical features disclosed in  FIGS. 1 ,  3  and  4  and the circuit of  FIG. 2 . However, the second connection box  7500  differs in that it utilizes the circuitry described in  FIG. 5 . Signal generating A/V equipment  702  optionally includes one or more of a video processor  711 , a DVD player  712  and a stereo receiver  713 . The A/V components receive power via cables  721 ,  722  and  723  respectively, all of which are connected to the output sockets on the back of power conditioning module  714  to receive filtered power, that is free from AC ripple and other noise signals that can ultimately affect the signal quality. It should be noted in the preferred embodiment all of the components receive filtered power from a common power conditioning module  714 , which is in turn connected to a wall outlet  703  via cord  742 , and thus wired to the main breaker panel  704  via cable  741 . 
     A/V system  700  includes a display, such as a wall mounted plasma television or monitor  715 , disposed remotely from the signal generating A/V equipment  702 . As a plasma display television is typically wall mounted rather than remote from the other components and the power conditioning module, it receives power via the remote connection box  7500  via cord  745 . Connection boxes  7500  and  7200  have their respective power plugs connected by cable  744 , which is behind the wall. The external plug  120  of connection box  7200  is connected to the common power-conditioning module by cable  743 , at plug  710  on the back of the signal-conditioning module. 
     As previously described with respect to  FIG. 5 , connection box  7500  preferably includes a filter circuit module disposed in serial connection between the input and output terminals of the L and N wires of the power socket portion of the connection box. Thus, any noise picked up by the power cable connection between connection box  7200  and connection box  7500  is suppressed by the capacitive filters. 
     As the power conditioning module  714  typically includes internal overvoltage and surge protection circuit modules, all the A/V components connected thereto are protected from power surges from either breaker panel  704  or electrical distribution cable  741  that supplies wall socket  703 . The common circuit protection components in the power-conditioning module  742 , thus provide a common ground reference at the same wall socket  703 . 
     The signal wires from the various A/V signal-generating components  702  plug into connection box  7200  at signal connection module  150 . Optionally, a single cable bundle  737  connects connection box  7200  with connection box  7500  such that the display  715 , and/or associated output speakers can be wired to nearby connection box  7500  via signal connection module  150 . As both connection boxes  7200  and  7500  deploy the surge and voltage transient protection circuit of  FIG. 2 , the signal and power circuitry of the all the interconnected A/V components share a common ground, offering more reliable protection from voltage and current transients of any origin. 
     Thus, the display  715 , signal generating A/V components  702  and power conditioning module  714  have a common ground connection with multiple layers of surge protection appropriate to low voltage signal lines, as well as AC powered circuitry. 
     It should be appreciated that the various configurations of connection boxes and alternative embodiments of internal circuitry are also advantageously deployed when the various A/V components do not receive power from a single power-conditioning module.  FIG. 8  is a schematic electrical circuit for the interconnection of A/V equipment wherein only the signal generating module(s) are connected to the power conditioning module  714 , display unit  715  being independently connected to the breaker panel as a power source. That is, the remote display  715  while similarly connected to connection box  8602  for signals, now receives power directly from a breaker panel  704  via AC power cable  8742 , which connects to the rear of the power socket module  120  in connection box  8602 . A connection box  8601  is deployed at the signal generation and power-conditioning module location and connects to the second connection box  8602 , deployed at the display device. 
     For both connection boxes  8601  and  8602 , the housing configuration preferably corresponds to the teachings of  FIGS. 1 ,  3  and  4 . As display  715  does not enjoy the overvoltage and surge protection from power conditioning module  714 , connection box  8602  deploys the internal circuitry of  FIG. 6 , offering protection from transient and sustained overvoltage conditions arising from AC power cable  8742 , or the breaker panel  704 . Thus, a further embodiment of the invention is the alternative circuit  800  for interconnecting A/V components  702  with a power-conditioning module  714  as previously described with respect to  FIG. 7 . Further, it should be appreciated that connection box  8602  provides a common ground reference between the signal wire and the power connections, while the display  715  has a common ground reference to the other A/V components, although not directly connected to power conditioning module  714 . 
     In the embodiments embraced by  FIGS. 7 and 8 , it should be further appreciated that the connection boxes are preferably wall mounted in close proximity to the A/V components, thus avoiding the cluttered appearance and hazards of multiple wiring cables exposed within the room. 
     It should be noted that in the more preferred embodiment&#39;s connection box  8601  (or  7200  in  FIG. 7 ) deploy a twist lock socket  120  for more secure connection to the power-conditioning module  714 . 
     It should be appreciated that the signal generating components  702  include any combination of one or more of CD player, a DVD player, satellite receiver, HD TV signal generator, stereo receiver, audio amplifier, signal generator, cable TV box and the like. Although the protection circuits of  FIGS. 2 ,  5  and  6  are preferably deployed within signal connection boxes having the mechanical features of  FIGS. 1 ,  3  and  4 , they may be deployed in other connection boxes housing power and signal wire connectors. Further, it should be appreciated that the A/V device connection circuits of  FIGS. 7 and 8  need not be limited to deploy only the preferred embodiments of the connection box and circuits therewith, but are also applicable to alternative connection boxes and surge or filter circuitry within the connection boxes, as might be varied to accommodate alternative types of A/V equipment. 
     While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims.