Abstract:
A device for controlling cable signals between a network cable and drop cables to customers includes an input for receiving cable signals; a first output connector for sending the cable signals to a first customer; a second output connector for sending the cable signals to a second customer; electronics selectively connecting the input to the first output connector so as to permit or deny a provision of the cable signals to the first customer, and selectively connecting the input connector to the second output connector to permit or deny provision of the cable signals to the second customer; and a cable modem, the cable modem capable of receiving instructions via the input and sending the instructions to the microprocessor and sending information via the input. A device for connecting between a cable tap and drop cables is also provided, as are various methods and cable systems.

Description:
[0001]    This claims priority to U.S. Provisional Application No. 60/784,122 filed Mar. 20, 2006 and hereby incorporated by reference herein. 
     
    
       [0002]    The present invention relates to cable television (CATV) systems, and more specifically to provisioning and receiving information about CATV services. 
       BACKGROUND INFORMATION 
       [0003]    Bi-directional CATV networks typically require service provisioning at the signal tap. The services provided are always available at all times at the signal tap in current cable systems. Thus, to disconnect the service from a customer requires a maintenance action at the signal tap to physically disconnect the cable linking the customer premises to the feed. To re-establish the service to a customer requires a maintenance action to connect the customer premises cable to the feed. These maintenance actions are often subcontracted by the cable company to a local cable maintenance service provider. Cable operators designate a team of technicians to audit at least 10% of the contractor&#39;s disconnect work. Cable operators have experienced unscrupulous subcontractors who report that the maintenance action to disconnect a cable to remove a customer from the network has been complete when, in fact, it has not. When a new customer takes over this customer premises, they will be already connected to the cable signal without having to pay for it. Unfortunately for the cable service provider, this type of theft can only currently be determined through a physical tap audit. Additionally, if a customer figures out how to connect him/her self to the cable feed, the cable signal can be ‘stolen’—again resulting in lost revenue to the cable service provider. 
         [0004]    Cable operators experience chums rates up to 60% of its subscribers&#39; base each year highlighting the significant number of transactions that are disconnected daily and the associated embedded cost to fulfill those disconnects. When those customers are disconnected appropriately, a significant number of those customers return as subscribers. When subscribers are not disconnected appropriately, cable operators lose access to those customers as new subscribers and the associated revenue. 
         [0005]    Disconnection of service is generally driven by slow or non-paying subscribers and those subscribers who move out of the cable operator&#39;s system. Today, those non-pay subscribers are soft disconnected around day  60  from when the bill is due. This applies to only those customers with set top boxes (STB) in the home. From the local office the cable operator is able to disable the STB with a remote command and premium services like HBO and Showtime are not available. Most customers are educated about the vulnerabilities of the cable system and know that if they disconnect the coax cable from the back of the STB and connect directly to the their television, they will have the basic programming tier, about 80 analog channels, until the service is hard disconnected by a technician. The reasons customers can continue to get the service is that the signal is always live at the cable tap irrespective of the condition of the box. 
         [0006]    Addressable taps permitting CATV service providers to turn on and off each subscriber at the tap level have been in limited use since 1983. These devices are an attempt to eliminate the need to manually connect and disconnect service by automatically switching the signal being delivered to each subscriber port on or off. The signal used to ‘address’ the tap is an FM modulated RF signal in the unused portion of the cable frequency spectrum (usually around 100 MHz). This communication capability, however, is only one way: from the control unit to the tap. Thus, there is no verification from the tap electronics that the command was received and acted upon, thus, eliminating the possibility of an electronic audit. Because these taps have the cable connected to them at all times, it is also difficult to physically audit them to make sure that customers are connected properly. Therefore, over time after the installation of the addressable tap, disconnects would be missed based upon the reliability of the communications media and equipment simply because the addressable tap cannot confirm the status of the connection for each port. It is assumed that connections would not be missed because customers would call in due to a lack of service that they were paying for. Thus, the cable operator is left with an unverifiable and unconfirmed connection status for its non-customers with an erosion of revenue being the result. In addition, cable television offerings have increased in complexity and addressable taps in the marketplace have limited ability (or no ability) to provision services meaning that a manual operation often must be done on the output of the addressable tap to add filtering customized to the service being provisioned. Addressable taps also represent a “re-build” of the existing network—they are not designed to be an add-on product. For these reasons, addressable taps have not gained wide range acceptance in the cable television market. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides a device for controlling cable signals between a network cable and drop cables to customers comprising:
       an input for receiving cable signals;   a first output connector for sending the cable signals to a first customer;   a second output connector for sending the cable signals to a second customer;   a circuit selectively connecting the input to the first output connector so as to permit or deny a provision of the cable signals to the first customer, and selectively connecting the input connector to the second output connector to permit or deny provision of the cable signals to the second customer; and       
 
         [0012]    a cable modem, the cable modem capable of receiving instructions via the input and sending information via the input. 
         [0013]    The present invention also provides a device for connecting a cable signal tap and drop cables to customers comprising:
       a first input connector for receiving cable signals from a first port of the signal tap;   a second input connector for receiving the cable signals from a second port of the signal tap;   a first output connector for sending the cable signals to a first customer;   a second output connector for sending the cable signals to a second customer; and a circuit connecting the first input connector to the first output connector and connecting the second input connector to the second output connector.       
 
         [0018]    The present invention also provides a control system for a cable network comprising: 
         [0019]    a plurality of electronically-controlled devices, each located between a network cable and a plurality of drop cables for customers and each having an a media access control address, and 
         [0020]    a server for controlling the electronically-controlled devices, the server selectively enabling provisioning of cable service to each customer. 
         [0021]    The present invention also provides a system for monitoring a cable network comprising: 
         [0022]    a plurality of electronically-controlled devices, each located between a network cable and a plurality of drop cables for customers and each having an a media access control address, and 
         [0023]    a server for receiving information on the electronic devices, the information providing information on the status of cable services to each customer. 
         [0024]    The present invention also provides a method for mapping a cable network comprising the step of sending information regarding the connection status of a plurality of drop cables from an off-premises cable modem. 
         [0025]    The present invention also provides a method for updated an existing cable network comprising attaching controllable switching devices to existing cable signal taps. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]    One preferred embodiment of the present invention will be described with respect to the following drawings in which: 
           [0027]      FIG. 1  shows a system according to one embodiment of the present invention; 
           [0028]      FIG. 2  shows a preferred embodiment of the device of the present invention using a controller module separate from a switch module; 
           [0029]      FIG. 3  shows a further embodiment of an integrated device of the present invention; 
           [0030]      FIG. 4  shows a block diagram of one embodiment of the controller module of the present invention with a single output connector powering a switch; 
           [0031]      FIG. 5  shows a block diagram of a controller module of the present invention with two output connectors; 
           [0032]      FIG. 6  shows different types of AC power that may exist in the cable network; 
           [0033]      FIG. 7  shows details of the input connector, signal splitter and AC-DC converter of the controller module of  FIG. 4 ; 
           [0034]      FIG. 8  shows details of temperature sensor, microprocessor support electronics, microprocessor and DC-DC converter of the controller module of  FIG. 4 ; 
           [0035]      FIG. 9  shows details of the communications controller of the controller module of  FIG. 4 ; 
           [0036]      FIG. 10  shows details of the serial transmitter/receiver and output connectors of the controller module of  FIG. 4 ; 
           [0037]      FIG. 11  shows one embodiment of an eight port switch module; 
           [0038]      FIG. 12  shows details of the input connectors, signal splitters, SPDT switches and output connectors of the  FIG. 11  embodiment; 
           [0039]      FIG. 13  shows details of the SP4T switches and power sensors of the  FIG. 11  embodiment; 
           [0040]      FIG. 14  shows details of the microprocessor of the  FIG. 11  embodiment; 
           [0041]      FIG. 15  shows details of the DC-DC converters of the  FIG. 11  embodiment; 
           [0042]      FIG. 16  shows details of the serial power connectors of the  FIG. 11  embodiment; 
           [0043]      FIG. 17  shows details of the serial transmitter/receiver of the  FIG. 11  embodiment; and 
           [0044]      FIGS. 18 and 19  show details of the support electronics of the  FIG. 11  embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0045]      FIG. 1  shows schematically one embodiment of the present invention showing a hybrid fiber coax cable network architecture having a head end  25  connected to a fiber optic loop  20 , and branched network cables  40 ,  41 ,  42 . Switching devices  1000 ,  1001 ,  1002 ,  1003  of the present invention located between taps  30 ,  31 ,  32 ,  33  of the network cables  40 ,  41 ,  42 . In this example, each switching device  100  is known uniquely by service monitoring and provisioning software  10  in a server  12  of a remote operations center  14 . 
         [0046]    Server  12  may also have a memory storing customer information. For example, a database may store the following information: 
         [0047]    Device  1000  port A is connected to customer premise 267 ABC Lane 
         [0048]    Device  1000  port B is connected to customer premise 269 ABC Lane 
         [0049]    Device  1000  port C is connected to customer premise 271 ABC Lane 
         [0050]    Device  1000  port D is connected to customer premise 273 ABC Lane 
         [0051]    Device  1001  port A is connected to customer premise 22 Main St 
         [0052]    Device  1001  port B is connected to customer premise 24 Main St 
         [0053]    Device  1002  port A is connected to customer premise 123 Industrial Way, Suite 1 
         [0054]    Device  1002  port B is connected to customer premise 123 Industrial Way, Suite 2 
         [0055]    Device  1002  port C is connected to customer premise 123 Industrial Way, Suite 3 
         [0056]    Device  1002  port D is connected to customer premise 123 Industrial Way, Suite 4 
         [0057]    Device  1003  port A is connected to customer premise 453 Apartment Ave, #701. 
         [0058]    Device  1003  port B is connected to customer premise 453 Apartment Ave, #603 
         [0059]    Device  1003  port C is connected to customer premise 453 Apartment Ave, #501 
         [0060]    Device  1003  port D is connected to customer premise 453 Apartment Ave, #402 
         [0061]    Device  1003  port E is connected to customer premise 453 Apartment Ave, #301 
         [0062]    Device  1003  port F is connected to customer premise 453 Apartment Ave, #201 
         [0063]    Device  1003  port G is connected to customer premise 453 Apartment Ave, #202 
         [0064]    Device  1003  port H is connected to customer premise 453 Apartment Ave, #203 
         [0065]    Each switching device  1000 ,  1001 ,  1002 ,  1003  can automatically provision each port as will be described, and this provisioning can be controlled by software  10  from the server  12  in center  14 . The switching devices advantageously may be connected between existing signal taps and the drop cables  70  of customers using connector cables  80 , and thus may be installed easily within existing cable networks. 
         [0066]    Each switching device may have a unique identifier, and with the network database and the capability to uniquely address each port, service can be automatically provisioned to each location to reduce cable theft occurrence and reduce maintenance costs. Cable connects and disconnects can be automated. The system advantageously is compatible with existing cable network head-end software requiring only the provisioning of a MAC address for each switching device deployed. IP protocol signals can be used to communication between a cable modem in the switching device and the head end, which also may have a cable modem. 
         [0067]    The switching devices  1000 ,  1001 ,  1002 ,  1003  are designed to be physically deployed alongside the signal taps  30 ,  31 ,  32 ,  33  in the cable network, although they could be integrated with tap technology and be used to replace signal taps or in new networks. Switching devices connect between the signal tap and customer premise as shown for example in  FIG. 2  with a switch module/controller module configuration defining the switching device, or  FIG. 3  with an 8-port signal tap switching device  1003 . Connections can be made for example using locking connectors  50  to help ensure the integrity of the connections. 
         [0068]    Software  10  permits changing the service state for a customer, so that via a graphical user interface an operator can choose the customer and change the service state via for example a GUI selection. The server  12  then sends a message via the cable network to the relevant switching device  1000  to  1003 . The service states that could be chosen include that cable service is disconnected at the identified port or cable service is connected for all services at the identified port. 
         [0069]    The switching devices  1000  also advantageously provide a cable provider the ability to map the cable network. The connection between a given port and customer premises is known and required to be known in order to provision services correctly, and can be communicated to the head end at predetermined times or based on queries from the software  10 . This knowledge can be a large advantage when determining the cause of inadvertent service disruptions or quickly restoring service following disruption due to weather or other catastrophic events. As an example, if, in a HFC network, a certain number of switching devices fail to report connectivity following a hurricane, but others upstream along the same cable branch do report, the cause of reporting failure is likely due to a cable break between two service cabinet locations along the network branch. As an additional example, if a customer reports a cable outage at their home, but the switching device, which is off-premise, reports a connection, the likely cause of cable disconnect is either in the customer premise or a break in the cable between the switching device and the premise. In either case, detailed information regarding the cause of service disruption can be provided to the service technician resulting in a reduced time to return service and less cost to the cable provider to do so. 
         [0070]      FIG. 2  shows one embodiment in which the switching device is implemented as a two-part expandable device, having a controller module  500 , and a plurality of four-port switching modules  100 . Controller module  500  can attach to an existing manual tap via a cable  82 , which provides the controller module to the RF signal and power, and permits the controller module  500  to receive and send signals to the head end  25 . Cable  84  can connect the controller module to switch modules  100 , each capable of connecting to another switch module via extender cables  86 . In this way a single controller module can control more than one switch module. 
         [0071]      FIG. 3  shows an alternate embodiment in which the switch module and controller module are integrated. The present invention will be described however with reference to the  FIG. 2  embodiment with separate switch and controller modules, which is advantageous in that it is expandable and the controller module can be used for other functions. 
         [0072]      FIG. 4  shows a detailed block diagram of the controller module  500  with an attached, remote switch module  1000 . The controller module  500  input connector  101  is a connector that is compatible with existing cable television network patch cables, such as an F connector jack. The input connector  101  is capable of passing AC power as well as the RF spectrum allocated within the cable network for modem operations (5 MHz to 50 MHz and 550 MHz to 850 MHz). The output of the input connector  101  carrying the composite RF+AC power signal feeds a signal splitter  110  designed to separate the AC signal and the RF signal. The AC signal is routed to an AC to DC converter circuit  120  to provide DC power for the controller module  500  and one or more switches  1000  while the RF signal is routed to an optional RF power sensor  270  and the cable modem emulation electronics  200 . The signal splitter  110  is designed such that the AC power signal is heavily attenuated when viewed at the signal splitters&#39;  110  RF port output and the RF signal is heavily attenuated when viewed at the signal splitters&#39;  110  AC port output. The AC to DC converter  120  is designed to convert a 60V to 90V, 60 Hz AC square wave, quasi-square wave, or sine wave input to a DC voltage necessary to support the cable modem emulation electronics  200  and peripheral switch modules  1000 , such as +12V DC. The resulting DC power signal is used to power various functions in the controller module  500  and switch modules  1000 . The DC to DC converter  250  is designed to convert the output of the AC to DC converter  120  to an alternate voltage level compatible with TTL electronics assuming that the AC to DC converter  120  output voltage is incompatible with these devices. The optional RF power sensor  270  samples and measures the output power from the cable modem emulation electronics  200 . The output of the optional RF power sensor  270  may be either in a digital form or an analog voltage. In the diagram of  FIG. 4 , the optional RF power sensor  270  output is assumed to be digital and is directly connected to the microprocessor  310  bus. If the output of the optional RF power sensor were an analog voltage, it would require connection to an analog to digital conversion port within the microprocessor  310  or to an external analog to digital converter whose digital output would then be connected to the microprocessor  310  bus. The RF power level measured by the optional RF power sensor  270  is useful diagnostic information for testing the controller module  500  and may be sent to the web based software  10 , represented in  FIG. 1 , to use for diagnostic or other purposes. 
         [0073]    The cable modem emulation electronics  200  offer the full functionality of a standard cable modem with respect to the cable network interface. However, the cable modem emulation electronics  200  are not necessarily required to support the full functionality required to connect to a standard personal computer. In  FIG. 4 , the cable modem emulation electronics  200  are connected to an optional communication controller  290 . The optional communication controller  290  could be a universal serial bus (USB) controller or Ethernet controller as examples. This allows the freedom to either directly connect the cable modem emulation electronics  200  to the microprocessor  310  bus or through an optional communication controller  290 . Existing cable modem systems are considered to be mature systems with respect to both hardware and software performance and reliability. Thus, connecting the microprocessor  310  through an optional communication controller  290  offers the advantage that existing cable modem technology may be used to implement the cable modem emulation electronics  200  function. Alternately, the cable modem emulation electronics  200  may be connected directly to the microprocessor  310  bus which has the advantage of eliminating unnecessary cable modem hardware functions used to support a personal computer interface with the potential penalty of increased software development. 
         [0074]    The microprocessor  310  provides for a programmable device supporting the controller module  500  device tasks. Alternate to microprocessor  310 , an application specific integrated circuit (ASIC) or other hardwired logic without software could be provided. The microprocessor  310  acts as the primary communication hub between the controller module  500  and the web-based software  10  of  FIG. 2 . Messages or data sent from the web-based software  10  of  FIG. 1  to the controller module  500  are received by the microprocessor  310 , decoded, acknowledged, and acted upon. Messages or data sent from the web-based software  10  of  FIG. 1  may be commands, requests for status, downloads of updated software, or other requests and commands. Similarly, messages or data to be sent to web-based software  10  of  FIG. 1  from the controller module  500  can be initiated by the microprocessor  310 . Messages to the web-based software  10  of  FIG. 1  may include the switch status for each output connector, temperature information or other diagnostic information, and maybe preset based on times or may be operated initiated. 
         [0075]    The microprocessor support electronics  350  includes the power-up reset logic for the microprocessor  310 , LED&#39;s, crystal oscillator circuits to provide a time reference for the microprocessor  310 , digital memory, and other components. A temperature sensor  330  allows the microprocessor  310  to report the temperature environment of the controller module  500  to the web-based software  10  of  FIG. 1 . 
         [0076]    The controller module  500  of  FIG. 4  includes a serial transmit/receiver  370  for communication with switch modules  1000 . The serial TX/RX  370  may be implemented as RS-232, RS-422, low voltage differential signaling (LVDS), or other communication technology. The purpose of the serial TX/RX  370  is to allow the controller module  500  to act as a transponder for peripheral devices such as the switch  1000  of  FIG. 4 . The output connector  390  of the controller module provides main DC power from the AC to DC converter  120  to peripheral devices, serial TX/RX  370  communication functionality, and digital signaling to and from the microprocessor  310 . The controller module  500  may include more than one output connector  390  with the indicated functionality to control one or more switches  1000 s.  FIG. 4  shows a single output connector  390  for simplicity sake. 
         [0077]    The switch module  1000  is connected to the controller module  500  through a cable  900 . The cable  900  may be of any length compatible with the signaling requirements required for the serial TX/RX  370  function and the digital signaling requirement of the microprocessor  310  and internal digital components of the security device  1000 . This allows the security device  1000  to be installed remotely from the controller module  500  or locally with the controller module  500  based upon customer installation desires. The cable  900  is attached to an input connector  1050  on the security device  1000  to electrically connect the security device  1000  to the controller module  500 . The DC power lines in the cable  900  are routed to the electronic switch  1110  and a DC to DC converter  1070 . The DC to DC converter  1070  is designed to convert the DC voltage of the supplied power to an alternate voltage level compatible with TTL electronics assuming that the voltage of the supplied power is incompatible with these devices. 
         [0078]      FIG. 5  shows a similar controller module  500 , but with two output connectors  390  and  391 . Thus one output connector could be used for one switch module  100  and the second for a second switch module in an alternate embodiment, so that two switch modules  100  are not necessarily connected in series as in  FIG. 2 . 
         [0079]      FIG. 6  shows square wave  1 , quasi-square wave  2 , and sine wave  3  representation of the different types of AC power that may exist in the cable network. The power in modern cable networks in the United States have voltages ranging from 60 VAC to 90 VAC at a 60 Hz cycle rate where the cycle rate is computed as 1/T in  FIG. 5 . These voltage levels represent the root-mean-squared voltage levels. For the square wave  1  of  FIG. 5 , the peak voltage is equal to the root mean squared voltage or V pk =V rms . For the sine wave  3  of  FIG. 5 , the peak voltage is equal to √{square root over (2)} times the root mean squared voltage or V pk =√{square root over (2)}V rms . The square wave  1  and sine wave  3  represent the minimum and maximum peak voltage bounds for the AC power in cable television networks. Thus, the minimum peak voltage would occur in a 60VAC system that uses a square wave  1  generator and the minimum peak voltage would be 60 V. The maximum peak voltage would occur in a 90 VAC system that uses a sine wave  3  generator and the maximum peak voltage would be 127.3 V. 
         [0080]      FIGS. 7 to 16  show a detailed schematic diagram of an instantiation of the present invention whereby one or more switch modules  100  are remotely controlled by a controller module. This particular instantiation utilizes a commercially available cable modem such as the Webstar DPC2100R2 series cable modem from Scientific Atlanta for the cable modem emulation electronics  200  of  FIG. 4 . 
         [0081]      FIG. 7  is a detailed schematic of an instantiation of the input connector  101 , signal splitter  110 , and AC to DC Converter  120  of  FIG. 4 . Input connector  101  in this instantiation of the invention may include a printed circuit board mounted F connector with four ground connections and a single center conductor carrying the composite RF and AC power connector. The signal splitter  110  of  FIG. 4  is comprised of the components F 1 , C 5 , L 75 , L 1 , L 2 , R 1 , R 2 , and C 2 . F 1  is a positive temperature coefficient (PTC) fuse designed to cause an open circuit condition when a steady-state current flow through the device exceeds its specification. The purpose of including a PTC fuse at the controller module  500  input is to safeguard the network and installation locations against hazards due to potential short circuit conditions that may develop within the controller module  500  or the security device  1000 . F 1  is capable of handling up to approximately 130 peak volts, and is capable of passing the full spectrum of DC to 1 GHz, and should be chosen for over-current conditions exceeding the anticipated current draw of the controller module  500  and attached security devices  1000  or other peripherals. 
         [0082]    The capacitor, C 5 , is chosen to present a low impedance to signals between 5. MHz and 850 MHz and a high impedance to the 60 Hz AC power signal and lower order harmonics if the power signal is a square wave  1  of  FIG. 5  or quasi-square wave  2  of  FIG. 5 . The impedance, Z, of the capacitor, C 5 , is given by 
         [0000]    
       
         
           
             
               
                 
                   Z 
                   = 
                   
                     1 
                     
                       2 
                       * 
                       π 
                       * 
                       f 
                       * 
                       C5 
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   1 
                 
               
             
           
         
       
     
         [0000]    Where: π if the value pi which is equal to 3.141592 . . . 
         [0083]    f is the frequency in hertz 
         [0084]    C 5  is the capacitance of the component, C 5 , in Farads 
         [0085]    Z is the resulting impedance magnitude in Ohms 
         [0086]    In addition to impedance considerations, the capacitor, C 5 , is also be capable handling potential high voltages on the cable line due to power transients or lightning strikes. It is also desirable for C 5  to have a low effective series resistance and effective series inductance. If a suitable single capacitor cannot meet the designers&#39; requirements two or more capacitors may be put in parallel with one another. 
         [0087]    The components L 75 , L 1 , L 2 , R 1 , R 2 , and C 2  in this embodiment are chosen to present a low impedance to the 60 Hz AC power signal and a high impedance to the RF signals between 5 MHz and 850 MHz. The components L 75 , L 1 , L 2 , R 1 , and R 2  represent a distributed RF choke. Cable systems are 75Ω systems, so the composite impedance of the distributed RF choke should be at least greater than 750Ω over the 5 MHz to 850 MHz frequency range to avoid unnecessary insertion loss due to the presence of the RF choke. Inductive components such as L 75 , L 1 , and L 2  have an effective capacitance between turns of the wire coil which produces a self capacitance that in combination with the inductance produces an LC resonance. For broadband applications such as this, the resonances often lie with the band of the RF signal. Reduction in the number of turns of the inductor can push any LC resonances above the passband, but this reduction will also result in a lower inductance limiting the effectiveness of the inductor at the low end (5 MHz) of the band. The distributed choke in the present invention overcomes these problems by having an inductor, L 75 , with a low number of turns with good rejection capabilities in the mid and upper frequencies of the RF signal band and resonances outside the band of the RF signal in series with inductors, L 1  and L 2 , which have a higher number of turns for low frequency rejection. The impedance, Z, of the inductive components is given by 
         [0000]        Z= 2 *π*f*L   Eq. 2 
         [0000]    Where: π if the value pi which is equal to 3.141592 . . . 
         [0088]    f is the frequency in hertz 
         [0089]    L is the inductance in Henry&#39;s 
         [0090]    Z is the resulting impedance magnitude in Ohms 
         [0091]    The resistors, R 1  and R 2 , are in parallel with the inductors, L 1  and L 2 , to reduce the Q of the LC resonance of the inductors which has the effect of dulling the response of any in-band resonances of L 1  or L 2 . The capacitor, C 2 , is chosen to present a low impedance to signals between 5 MHz and 850 MHz to provide an RF path to ground on the power output leg of the signal splitter  110  of  FIG. 4  and a high impedance to the 60 Hz AC power signal. 
         [0092]    The components R 16 , D 4 , R 17 , D 5 , D 6 , D 10 , C 19 , C 32 , C 43 , C 44 , C 46 , and C 47  half-wave rectify the 60 Hz AC power signal, reduce the peak voltage to the input voltage range of the switching regulation circuitry, and provides voltage hold-up during the negative voltage half-cycle of the AC power input. The resistor, R 16 , is used to help limit the in-rush currents at initial application of power. The diodes, D 4  and D 5 , are used to create the half-wave rectifier circuit. The zener diodes, D 6  and D 10 , are optional components used to limit the peak voltage present at the node, Vin of U 1 , to within the requirements of the components attached to the node. The capacitors, C 19  and C 32 , are anticipated to provide bulk capacitance for maintaining the voltage between rectification cycles. While two capacitors are shown in the current instantiation, one may be adequate or more than two required depending upon the components chosen. To prevent large input transients, it is desirable to have a low equivalent series resistance for the total capacitance at the node, Vin of U 1 . The capacitors, C 43 , C 44 , C 46 , and C 47 , are anticipated to be low ESR capacitors such as ceramics. The rationale for using both bulk capacitors and ceramics is that bulk capacitor technologies generally do not have adequate ESR for applications such as this while ceramic capacitors or other low ESR technologies do not have adequate total capacitance at the anticipated required voltage levels. Thus, the parallel combination of the two technology types represents a good approach for implementation. 
         [0093]    The AC to DC converter  120  is anticipated to be a switching power supply that supplies a voltage output, VDC Out, at a max output current of I MAX  with a regulation efficiency of E. Thus, the power required to be supplied by the cable television system can be computed as: 
         [0000]    
       
         
           
             
               
                 
                   
                     P 
                     source 
                   
                   = 
                   
                     
                       VDC 
                        
                       
                           
                       
                        
                       Out 
                       * 
                       
                         I 
                         MAX 
                       
                     
                     ɛ 
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   3 
                 
               
             
           
         
       
     
         [0094]    Where: VDC Out is the AC to DC Converter  120  output voltage 
         [0095]    I MAX  is maximum AC to DC Converter  120  output voltage 
         [0096]    is the efficiency of the regulator. 
         [0097]    P SOURCE  is the power to by supplied by the cable television system 
         [0098]    With the voltage regulation circuitry designed for this instantiation of the present invention, the maximum current draw from the host cable system occurs when the host system has a minimum peak voltage. The minimum peak voltage (60 V) available from the potential AC voltage waveforms occurs when the voltage waveform is a 60 VAC square wave as determined previously. Thus, the minimum rectified voltage present at the node, Vin of U 1 , when the capacitors, C 19  and C 32  are fully charged is given by: 
         [0000]        V   in of U1 =60 V− V   Zener   −I   Source   *R 16−0.7 V  Eq. 4   Where: V in of U1  is the voltage present at the node, Vin of U 1 , when the capacitors, C 19  and C 32 , are fully charged     
         [0100]    V Zener  is the voltage drop across the Zener diodes, D 6  and D 10   
         [0101]    I source *R 16  is the voltage drop across the resistor, R 16   
         [0102]    0.7 V is the estimated voltage drop across the diode, D 5   
         [0103]    Given the result of Eq. 4, the power required to be supplied by the cable television system can be written as: 
         [0000]        P   SOURCE =(60 V− V   Zener   −I   Source   *R 16−0.7 V)* I   Source   Eq. 5 
         [0000]    Equating the result of Eq. 5 to the result of Eq. 3 and solving for I Source  yields 
         [0000]    
       
         
           
             
               
                 
                   
                     I 
                     source 
                   
                   = 
                   
                     
                       
                         
                           
                             
                               ( 
                               
                                 
                                   60 
                                    
                                   
                                       
                                   
                                    
                                   V 
                                 
                                 - 
                                 
                                   V 
                                   Zener 
                                 
                                 - 
                                 
                                   0.7 
                                    
                                   
                                       
                                   
                                    
                                   V 
                                 
                               
                               ) 
                             
                             ± 
                           
                         
                       
                       
                         
                           
                             
                               
                                 
                                   
                                     
                                       
                                         ( 
                                         
                                           
                                             60 
                                              
                                             
                                                 
                                             
                                              
                                             V 
                                           
                                           - 
                                           
                                             V 
                                             Zener 
                                           
                                           - 
                                           
                                             0.7 
                                              
                                             
                                                 
                                             
                                              
                                             V 
                                           
                                         
                                         ) 
                                       
                                       2 
                                     
                                     - 
                                     
                                       4 
                                       * 
                                     
                                   
                                 
                               
                               
                                 
                                   
                                     R 
                                      
                                     
                                         
                                     
                                      
                                     16 
                                     * 
                                     
                                       ( 
                                       
                                         
                                           VDC 
                                            
                                           
                                               
                                           
                                            
                                           Out 
                                           * 
                                           
                                             I 
                                             MAX 
                                           
                                         
                                         ɛ 
                                       
                                       ) 
                                     
                                   
                                 
                               
                             
                           
                         
                       
                     
                     
                       2 
                       * 
                       R 
                        
                       
                           
                       
                        
                       16 
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   6 
                 
               
             
           
         
       
       
         Where: I SOURCE  is the current that required to be supplied by the cable television system
       (60 V−V Zener −I Source *R 16 −0.7 V) is the voltage present at the node, Vin of U 1 , when the capacitors, C 19  and C 32 , are fully charged   R 16  is the in-rush current suppression resistor   VDC Out is the AC to DC Converter  120  output voltage   I MAX  is maximum AC to DC Converter  120  output voltage   ε is the efficiency of the regulator   
     
       
     
         [0110]    The choice of V Zener  is determined by the reduction in the maximum peak voltage required to limit the voltage present at the node, Vin of U 1 , based upon the requirements of the components attached to this node. As shown in the discussion for  FIG. 5 , the maximum peak voltage would occur when the input AC power waveform is a sine wave. R 16  is then chosen based upon the maximum current draw from the host cable television system for each installed instantiation of the present system. Eq. 7 is a restatement of Eq. 6 for the solution of R16 if the maximum current to be supplied by the cable television system is known. 
         [0000]    
       
         
           
             
               
                 
                   
                     R 
                      
                     
                         
                     
                      
                     16 
                   
                   = 
                   
                     
                       
                         
                           
                             
                               
                                 ( 
                                 
                                   
                                     60 
                                      
                                     
                                         
                                     
                                      
                                     V 
                                   
                                   - 
                                   
                                     V 
                                     Zener 
                                   
                                   - 
                                   
                                     0.7 
                                      
                                     
                                         
                                     
                                      
                                     V 
                                   
                                 
                                 ) 
                               
                               * 
                               
                                 I 
                                 SOURCE 
                               
                             
                             - 
                           
                         
                       
                       
                         
                           
                             ( 
                             
                               
                                 VDC 
                                  
                                 
                                     
                                 
                                  
                                 Out 
                                 * 
                                 
                                   I 
                                   MAX 
                                 
                               
                               ɛ 
                             
                             ) 
                           
                         
                       
                     
                     
                       
                         ( 
                         
                           I 
                           SOURCE 
                         
                         ) 
                       
                       2 
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   7 
                 
               
             
           
         
       
     
         [0111]    During the negative half-cycle of the AC voltage signal, the voltage present at the node, Vin of U 1 , should not drop below a minimum voltage, V min , to avoid dropouts in the regulated voltage output, VDC Out. To determine the minimum bulk capacitance required to hold up the voltage above the V min  threshold can be estimated by assuming that the rectifier load is approximately resistive. The minimum resistance of the rectifier load, R min  coincides with the condition when the minimum peak voltage (60 V) available from the potential AC voltage waveforms occurs. R min  can be determined as: 
         [0000]    
       
         
           
             
               
                 
                   
                     R 
                     min 
                   
                   = 
                   
                     
                       
                         ( 
                         
                           
                             60 
                              
                             
                                 
                             
                              
                             V 
                           
                           - 
                           
                             V 
                             Zener 
                           
                           - 
                           
                             0.7 
                              
                             
                                 
                             
                              
                             V 
                           
                         
                         ) 
                       
                       - 
                       
                         
                           I 
                           SOURCE 
                         
                         * 
                         R 
                          
                         
                             
                         
                          
                         16 
                       
                     
                     
                       I 
                       SOURCE 
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   8 
                 
               
             
           
         
       
     
         [0000]    Where: R min  is the modeled minimum resistance of the rectifier load
       (60 V−V zener −I Source *R 16 −0.7 V) is the voltage present at the node, Vin of U 1 , when the capacitors, C 19  and C 32 , are fully charged   R 16  is the in-rush current suppression resistor   I SOURCE  is calculated current of Eq. 6       
 
         [0115]    The bulk capacitance obtained by C 19  and C 32  is capable of holding up the voltage above V min  during the negative voltage half-cycle under the minimum peak voltage condition given by a 60 VAC square wave input. Thus, 
         [0000]    
       
         
           
             
               
                 
                   
                     V 
                     min 
                   
                   ≤ 
                   
                     
                       ( 
                       
                         
                           60 
                            
                           
                               
                           
                            
                           V 
                         
                         - 
                         
                           V 
                           Zener 
                         
                         - 
                         
                           
                             I 
                             Source 
                           
                           * 
                           R 
                            
                           
                               
                           
                            
                           16 
                         
                         - 
                         
                           0.7 
                            
                           
                               
                           
                            
                           V 
                         
                       
                       ) 
                     
                     * 
                     
                        
                       
                         
                           - 
                           t 
                         
                         
                           
                             R 
                             min 
                           
                           * 
                           
                             ( 
                             
                               
                                 C 
                                  
                                 
                                     
                                 
                                  
                                 19 
                               
                               + 
                               
                                 C 
                                  
                                 
                                     
                                 
                                  
                                 32 
                               
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   9 
                 
               
             
           
         
       
       
         Where: V min  is the minimum voltage present at the node, Vin of U 1 , to avoid dropouts in the regulated voltage output, VDC Out.
       (60 V−V zener −I Source *R 16 −0.7 V) is the voltage present at the node, Vin of U 1 , when the capacitors, C 19  and C 32 , are fully charged   t is time   R min  is the modeled minimum resistance of the rectifier load   C 19 +C 32  is the bulk capacitance   
     
       
     
         [0121]    Using 1/120 th of a second as the time duration of the negative half cycle of the voltage waveform and solving for the bulk capacitance, C19+C32 yields    
         [0000]    
       
         
           
             
               
                 
                   
                     
                       C 
                        
                       
                           
                       
                        
                       19 
                     
                     + 
                     
                       C 
                        
                       
                           
                       
                        
                       32 
                     
                   
                   = 
                   
                     
                       - 
                       1 
                     
                     
                       
                         
                           
                             ln 
                              
                             
                               ( 
                               
                                 
                                   V 
                                   min 
                                 
                                 
                                   
                                     60 
                                      
                                     
                                         
                                     
                                      
                                     V 
                                   
                                   - 
                                   
                                     V 
                                     Zener 
                                   
                                   - 
                                   
                                     
                                       I 
                                       Source 
                                     
                                     * 
                                     R 
                                      
                                     
                                         
                                     
                                      
                                     16 
                                   
                                   - 
                                   
                                     0.7 
                                      
                                     
                                         
                                     
                                      
                                     V 
                                   
                                 
                               
                               ) 
                             
                             * 
                           
                         
                       
                       
                         
                           
                             
                               R 
                               min 
                             
                             * 
                             120 
                           
                         
                       
                     
                   
                 
               
               
                 
                   Eq 
                   . 
                   
                       
                   
                    
                   10 
                 
               
             
           
         
       
     
         [0122]    The regulator circuit in the instantiation of the present invention may use a regulator controller commercially-available from Linear Technologies with model number LTC3703, which is U 1  of  FIG. 7 . This is a synchronous step-down switching regulator controller that can directly step-down voltages from 100V and drives external N-channel MOSFET&#39;s using a constant frequency, voltage mode architecture. A precise internal reference provides 1% DC voltage output accuracy. A high bandwidth error amplifier and line feed forward compensation provide very fast line and load transient response. Strong gate drivers allow the LTC3703 to drive multiple MOSFETs for higher current applications. The operating frequency is user programmable from 100 kHz to 600 kHz and can also be synchronized to an external clock for noise-sensitive applications. Current limit is programmable with an external resistor and utilizes the voltage drop across the synchronous MOSFET to eliminate the need for a current sense resistor. 
         [0123]    The optional components, C 121 , C 119 , C 122 , C 120 , and L 73 , form a pi filter to increase the noise immunity and transient suppression of the LTC3703 regulator. 
         [0124]      FIG. 8  is a detailed schematic of an instantiation of the microprocessor  310 , the temp sensor  330 , the DC to DC converter  250 , and the microprocessor support electronics  350 . 
         [0125]    U 10 , C 11 , and optional C 29  in this embodiment represent the temperature sensor  330  components. U 10  is a broad range precision temperature sensor whose output voltage is linearly proportional to the temperature, such as the LM34 by National Semiconductor. The temperature sensor device in this instantiation has an analog output whose voltage level is linearly proportional to the Fahrenheit temperature and is be connected to one of the internal analog to digital converter inputs of the microprocessor  310 . This instantiation has an advantage over linear temperature sensing circuits calibrated in degrees Kelvin in that a large constant voltage is not required to be subtracted from its output to obtain conventional Fahrenheit scaling. The capacitor, C 11 , is a power supply de-coupling capacitor while the optional capacitor, C 29 , may help enhances noise immunity on the analog signal line. 
         [0126]    The components U 12 , R 10 , C 24 , R 9 , R 27 , D 3 , R 13 , R 26 , D 2 , R 12 , R 25 , D 1 , R 11 , Y 1 , C 3 , and C 4  represent the microprocessor support electronics  350  for the instantiation of the present invention. 
         [0127]    The microprocessor support electronics  350  includes the power-up reset logic for the microprocessor  310 , LED&#39;s, crystal oscillator circuits to provide a time reference for the microprocessor  310 , digital memory, and other parts. A temperature sensor  330  allows the microprocessor  310  to report the temperature environment of the controller module with security device  100  to the web-based software  10  of  FIG. 1 . D 3 , R 27 , and R 13  form a light-emitting diode (LED) circuit. The light emitting diode, D 3 , can be turned on or off by the microprocessor  310  and acts as visual indication of the state of the dynamic host configuration protocol (DHCP) when the controller module  500  is requesting an internet protocol (IP) address. When the microprocessor  310  output is a TTL high or ‘1’, the LED will be on and when the microprocessor output is a TTL low or ‘0’, the LED will be off. In the present instantiation, the LED, D 3 , is solid if DHCP is ready and will blink if a failure has occurred. The function of the LED, D 3 , can be changed by changing the microprocessor  310  software. 
         [0128]    D 2 , R 26 , and R 12  form another light-emitting diode circuit. In the present instantiation, D 2  will blink every 15 seconds to visually signal that the microprocessor  310  software is operating normally. The function of the LED, D 2 , can be changed by changing the microprocessor  310  software. 
         [0129]    D 1 , R 25 , and R 11  form a third light emitting diode circuit as part of the microprocessor support electronics  350 . In the present instantiation, D 1  is on to signal that external communications with a peripheral device such as the security camera  1000  is operating normally. The function of the LED, D 1 , can be changed by changing the microprocessor  310  software. 
         [0130]    Y 1 , C 3 , and C 4  form the clock oscillator circuit for the microprocessor  310 . Y 1  is a crystal oscillator such as an HCM49-10.000MAJB-UT, 10 MHz oscillator by Citizen America. The oscillator serves as the timing reference for the microprocessor  310 . Capacitors, C 3  and C 4 , serve as optional load capacitance to the crystal. 
         [0131]    The components U 2 , C 124 , C 126 , L 74 , C 125 , and C 127  represent the DC to DC converter  250  of the instantiation of the present invention. U 2  is a 3-terminal regulator, such as a μA78M05 by Texas Instruments, designed to step-down the voltage from VDC Out to +5 VDC. The components C 124 , C 126 , L 74 , C 125 , and C 127  form a pi filter to provide enhanced noise suppression to the +5 VDC output from the regulator. 
         [0132]    The component U 3  represents the microprocessor  310  of the instantiation of the present invention. The microprocessor  310  of the instantiation of the present invention has serial communication ports, parallel ports for direct processor interface, self-programmability meaning that the device can write to its own program memory spaces under direct software control, and built-in analog to digital conversion ports. A device meeting these characteristic requirements is the PICF6627 by Microchip Technology. 
         [0133]      FIG. 9  is a detailed schematic of the instantiation of the optional communication controller  290  of the controller module. U 4  is an Ethernet controller, such as the RTL8019AS by the microprocessor  310  bus. Use of an Ethernet controller allows the present instantiation to use existing, commercially-available cable modems such as the Webstar DPC2100R2 series cable modem from Scientific Atlanta. Optional light emitting diode circuits represented by R 19 , D 7 , R 20 , D 8 , R 21 , and D 9  allow visual indication of the link status, transmit activity, and receive activity for the Ethernet controller. 
         [0134]      FIG. 10  is a detailed schematic of the instantiation of the serial TX/RX  370  function and the output connect  390 . In the present instantiation, two output connectors  390  are implemented. The serial TX/RX  370  function of the instantiation of the present invention translates TTL serial information into RS-232 signaling for transport to peripheral devices such as the security camera  1000 . A device such as the LT1381CS by Linear Technology will accomplish the requirements of the serial TX/RX  370  function. The output connectors  390  provide the necessary serial communication, analog signaling, digital bus connections, power, and ground to operate peripheral devices. The power signal, VDC Out, is connected to the output connector  390  through a positive temperature coefficient fuse, F 2  and F 3 , to avoid damaging the controller module  500  circuitry due to an over-current condition in a peripheral device. 
         [0135]      FIG. 11  shows a eight port switch module  100 . Two serial/power connectors  601 ,  602  are provided, one of which is connected to the output connector  390  of the controller module  500  of  FIG. 4 . The other connector can be used for connection to a further switch module. The switch module  100  of  FIG. 11  is designed to accommodate eight independent ports per device primarily due to the prevalence of eight port taps in the cable network, but could be more or less based upon the CATV providers wishes. However, four port switch modules as shown in  FIG. 2  are also possible, and may be connected in series. One instantiation of the connectors  601 ,  602  is shown in  FIG. 16 . 
         [0136]    Switch module  100  is used to program automated service connects and disconnects for primarily bulk applications in the CATV network. In this embodiment, up to eight manual input connectors  611 ,  612 ,  613 ,  614 ,  615 ,  616 ,  617 ,  618  are provided, for example for each port of an eight port signal tap. Each input connector  611  to  618  can connect to a signal splitter  621 ,  622 ,  623 ,  624 ,  625 ,  626 ,  627 ,  628 , a single pole double throw (SPDT) switch  631 ,  632 ,  633 ,  634 ,  635 ,  636 ,  637 ,  638 , and an output connector  711 ,  712 ,  713 ,  714 ,  715 ,  716 ,  717 ,  718 , respectively. One instantiation of the input connector  611 , signal splitter  621 , SPDT switch  631  and output connector  711  is shown in  FIG. 12 . The switch  631  for example may be a SPDT HMC348LP3 switch commercially-available from the Hittite Microwave Corporation. It should be understood that all of the input connectors  611  to  618 , signal splitters  621  to  628 , SPDT switches  631  to  638  and output connectors  711  to  718  may be similar to this instantiation. 
         [0137]    The signal input connectors may be F connector jacks compatible with existing CATV network patch cables. The F connector is capable of passing the entire RF spectrum of 5′MHz to 850 MHz for cable network operations. Each output of the input connectors  611  to  618  feeds a respective signal splitter  621  to  628 . The signal splitters are designed to send approximately 1/10th of the signal power to an RF power sensor circuit  640  via a line  620  and switch  650  to allow the switch module  100  to sense whether or not the input cables are connected properly to each port. The other output  630  of the signal splitter is a low loss (approximately −0.5 dB) path that feeds a respective switch  631  to  638  that acts as the connect/disconnect mechanism. The output of the SPDT switch feeds to another output F connector  711  to  718  respectively that will connect to the drop cable going to the customer premise. 
         [0138]    The input connectors  611  to  618  may be compatible with locking connectors requiring a special tool to remove the connection. 
         [0139]    Power measurement line  620 , switch  650  and RF power sensor  640  are implemented to verify that the manual tap outputs are connected properly to make it difficult to steal cable by disconnecting the switch module. This RF power sensor circuit is designed to provide an analog voltage corresponding to a measurement of the input power. The input to the RF power measurement circuitry is accommodated via two single-pole, four throw (SP4T) switches  650  to individually direct each port input to the RF power sensor  640 .  FIG. 13  shows one possible instantiation for switch  650  and power sensor  640 . Switch  650  may include for example an SP4T switch model HMC241QS16E commercially-available from the Hittite Microwave Corporation. Switch  640  may include a power detector model LTC 5507 commercially-available from Linear Technology. 
         [0140]    Microprocessor  680  may be one commercially-available from Microchip Technology with model number PIC18F6627, as shown in  FIG. 14 . Alternately, microprocessor  680  could be replaced by an ASIC or other hardwired logic without software. Microprocessor  680  receives inputs and outputs from a serial transmitter receiver  690  and support electronics  695 . Microprocessor  680  acts as the communication and control element. Messages or data sent from the controller module  500  are received by microprocessor  680  and the appropriate commands are executed or data/measurements sent back to the controller module  500  through the serial transmitter/receiver  690 . 
         [0141]    One instantiation of transmitter/receiver  690  is shown in  FIG. 17 , and may include a driver receiver commercially-available from Linear Technology with model number LTI381CS. The serial Tx/Rx  690  allows the switch module  100  to communicate with the controller module  500 . Each switch module has a unique identifier (similar to a MAC address) that is used to identify the appropriate device. This allows multiple switch modules to be connected to a single controller module as shown in  FIG. 2  without creating addressing conflicts and potential control problems. Additionally, all communications between a switch module and the controller module can be initiated by the controller module  500  to minimize communication clashes that may occur on the serial communications lines by multiple devices attempting to transmit at the same time. 
         [0142]    Support electronics  695  includes the power-up reset logic for the microprocessor, LED&#39;s, crystal oscillator circuits, and temperature sensing to monitor the temperature of the switch module  100 .  FIG. 18  shows for example a temperature sensor  696  commercially-available from National Semiconductor, and  FIG. 19  a light-emitting diode commercially-available from Panasonic. Electronics  695  may also include a crystal oscillator such as an HCM49-10.000MAJB-UT, 10 MHz oscillator by Citizen America 
         [0143]    The switch module using the power sensor  640  can sense whether or not the input ports are connected. All tap ports typically are connected to a switch module in a given installation environment using switch modules even if there are more tap ports than customers. By connecting the tap port output to a switch module input as shown in  FIG. 2 , the service to a customer can controlled through the functions of the switch module. For a non-paying customer who is disconnected by the switch module to ‘steal’ the signal from the cable company, the thief would have to disconnect&#39; the cable going to his premise from the output of the switch module and also disconnect the input to the switch module to reconnect his premise cable directly to the tap, assuming that all tap outputs are connected to a switch module input. By measuring the input power for each port input, the switch module can recognize the change in connectivity state and alert the cable television provider to the possibility of cable theft. 
         [0144]    DC to DC converters  660 ,  670  shown in  FIG. 15  are designed to convert the +12V DC input from the controller module  500  to +5V DC to power the devices within the switch module  100 . Separate converters  660 ,  670  and supply lines  661 ,  671  for the RF and digital electronics, respectively, help ensure the minimization of digital switching noise corrupting the RF signal integrity. 
         [0145]    Controller module  500  can be set to provide information on the status of the switch modules at preset times, for example each night at 2 am, or at preset intervals, for example every hour, to the head end  25 . Cable modem  200  provides the information over normal cable modem frequencies. The controller module can also provide the status information in response to a query from the head end  25 . 
         [0146]    The switching devices of the present invention advantageously can be used to update an existing cable system by simply attaching to existing cable signal taps.