Abstract:
Various embodiments of patch panel devices are enclosed. In some embodiments, signals received are in an electrical or optical form and converted to the other form. The converted signal is provided as an output signal. A version of the original input may also be provided as an input. A signal injector can inject a optical or electrical signal that is selectively injected into the output signals. Various embodiments also include sensor to detecting the connecting of an electrical or optical line.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to the field of electrical and optical networking, and more particularly to the conversion, injection, and monitoring of electrical and optical signals. 
       BACKGROUND OF THE INVENTION 
       [0002]    The concept of using a patch port device for injecting and monitoring an electrical signal is well known. A patch port device is typically a passive symmetrical device, providing for an input port, an output port, a monitoring port, and an injection port. In the normal mode of operation, the patch port device simply allows for an input electrical signal to be passed through as an output electrical signal. However, there may occasionally be the need to inject another electrical signal as the output electrical signal or to monitor the input electrical signal. When an electrical cable is plugged into the monitoring port of the patch port device for monitoring the input electrical signal, the presence of the electrical cable at the monitoring port is physically detected so that the input electrical signal is no longer passed through as an output electrical signal. Instead, the input electrical signal is sent out to the electrical cable plugged in the monitoring port, controlled by a switch activated by the physical detection. Similarly, when an electrical cable is plugged into the injection port of the patch port device for injecting another electrical signal as the output electrical signal, the presence of the electrical cable at the injection port is physically detected so that the input electrical signal is no longer passed through as an output electrical signal. Instead, the injected signal coming from the electrical cable plugged in the injection port is sent out as the output electrical signal, controlled by a switch activated by the physical detection. 
         [0003]    Prior networks relied on electrical lines to transmit information. However, fiber optic lines of newer systems are capable of much higher rates of transmission. As the use of optical networks becomes more prevalent, there is a need for an alternative to the patch port device described above that can provide for injection and monitoring of optical signals, as well as existing electrical signals, in addition to being able to provide for conversion between optical and electrical signals. 
       SUMMARY OF THE INVENTION 
       [0004]    The invention provides in one aspect an optical patch panel device comprising: an optical input port for receiving an input optical signal; an electrical output port for transmitting an output electrical signal; an optical-to-electrical converter for generating the output electrical signal in response to the input optical signal; a signal monitor for monitoring at least one of the input optical signal or the output electrical signal; a signal injector having an active and an inactive mode; wherein, when the a signal injector is in its active mode: the signal injector is operative to allow injection of an injected optical signal or an injected electrical signal; the output electrical signal corresponds to the injected signal; if the injected signal is an optical signal, the converter is adapted to generate the output electrical signal corresponding to the injected signal; if the injected signal is an electrical signal, the converter is inoperative (or alternatively switched out of the circuit); and wherein, when the signal injector is in its inactive mode, then the converter generates the output electrical signal corresponding to the input optical signal. 
         [0005]    The invention provides in another aspect an optical patch panel device comprising: an electrical input port for receiving an input electrical signal; an optical output port for transmitting an output optical signal; an electrical-to-optical converter for generating the output optical signal in response to the input electrical signal; a signal monitor for monitoring at least one of the input electrical signal or the output optical signal; a signal injector having an active and an inactive mode; wherein, when the signal injector is in its active mode: the signal injector is operative to allow injection of an injected optical signal or an injected electrical signal; the output optical signal corresponds to the injected signal; if the injected signal is an electrical signal, the converter is adapted to generate the output optical signal corresponding to the injected signal; if the injected signal is an optical signal, the converter is inoperative (or alternatively switched out of the circuit); and wherein, when the signal injector is in its inactive mode, then the converter generates the output optical signal corresponding to the input electrical signal. 
         [0006]    The invention further provides in another aspect the signal injector is controlled by a sensor that senses the connection of at least one of a second optical signal or a second electrical signal, wherein the sensor may be comprise: a) a light emitter and a light sensor, b) two capacitance plates, c) a micro-switch and a button, and d) a micro-switch and one or more switch arms. 
         [0007]    In some embodiments, the optical patch panel device may be hot-swappable. 
         [0008]    Further aspects and advantages of the invention will appear from the following description taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show some examples of the present invention, and in which: 
           [0010]      FIG. 1  is a block diagram of an example implementation of a switching system using an optical-to-electrical patch panel device and an electrical-to-optical patch panel device of the present invention; 
           [0011]      FIG. 2  is an illustrative block diagram of the optical-to-electrical patch panel device of  FIG. 1 ; 
           [0012]      FIG. 3  is an illustrative block diagram of the electrical-to-optical patch panel device of  FIG. 1 ; 
           [0013]      FIG. 4  is a cross-sectional diagram of an example implementation of an incoming cable and a cable receptacle of either the optical-to-electrical patch panel device of  FIG. 2  or the electrical-to-optical patch panel device of  FIG. 3  having a sensor including a light emitter and a light sensor; 
           [0014]      FIG. 5  is a cross-sectional diagram of an example implementation of an incoming cable and a cable receptacle of either the optical-to-electrical patch panel device of  FIG. 2  or the electrical-to-optical patch panel device of  FIG. 3  having a sensor including capacitance plates; 
           [0015]      FIG. 6A  is a cross-sectional diagram of an example implementation of an incoming cable and a cable receptacle of either the optical-to-electrical patch panel device of  FIG. 2  or the electrical-to-optical patch panel device of  FIG. 3  having a sensor including a micro-switch; 
           [0016]      FIG. 6B  is a cross-sectional diagram of an example implementation of an incoming cable and a cable receptacle of either the optical-to-electrical patch panel device of  FIG. 2  or the electrical-to-optical patch panel device of  FIG. 3  having a sensor having a micro-switch; and 
           [0017]      FIG. 7  is a diagram illustrating the physical implementation of either the optical-to-electrical patch panel device of  FIG. 2  or the electrical-to-optical patch panel device of  FIG. 3 ; 
       
    
    
       [0018]    It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. 
       DESCRIPTION OF THE INVENTION 
       [0019]    Reference is first made to  FIG. 1  showing an example implementation of a switching system  100  using an optical-to-electrical patch panel device  110  and an electrical-to-optical patch panel device  130  of the present invention. Switching system  100  is adapted for receiving an input-side incoming optical signal  105  and transmitting output-side outgoing optical signal  135 . Input-side incoming optical signal  105  and output-side outgoing optical signal  135  may be any type of optical signal carrying any content. 
         [0020]    In the normal mode of operation, on the input-side of switch  120 , an input-side incoming optical signal  105  is received by an optical-to-electrical patch panel device  110  and transmitted as an input-side outgoing electrical signal  115 . The input-side outgoing electrical signal  115  is then passed through switch  120  and transmitted as an output-side incoming electrical signal  125 . The output-side incoming electrical signal  125  is received by an electrical-to-optical patch panel device  130  and transmitted as an output-side outgoing electrical signal  135 . Additionally, the output-side outgoing optical signal  135  may then be passed through a distribution amplifier  140 , generating distributed output optical signals  145  for further transmission. 
         [0021]    Switch  120  is capable of forming a connection between any input and any output, and preferably, should form a plurality of simultaneous connections. Where a connection is formed, the desired input signal is conveyed to the desired output signal. It should be noted that although in the example implementation of switching system  100 , switch  120  is an electrical switch, switch  120  may be any kind of switch depending on the type of input and output signals it receives. For example, switch  120  may be an optical switch if it receives an optical signal from electrical-to-optical patch panel device  130  and generates an optical signal for optical-to-electrical patch panel device  110 . 
         [0022]    Reference is next made to  FIG. 2  illustrating optical-to-electrical patch panel device  110  for use in switching system  100 . Optical-to-electrical patch panel device  110  is adapted to provide a signal converter, as well as signal injection and signal monitoring. It should be noted that optical-to-electrical patch panel device  110  does not necessarily have to be on the input-side of switch  120 , rather, optical-to-electrical patch panel device  110  may be any patch panel device adapted for optical-to-electrical signal conversion in a switching system. 
         [0023]    Optical-to-electrical patch panel device  110  has input-side incoming optical signal port  282  for receiving input-side incoming optical signal  105  and input-side outgoing electrical signal port  280  for transmitting input-side outgoing electrical signal  115 . 
         [0024]    Optical-to-electrical patch panel device  110  may additionally include ports for injecting either an electrical inject signal or an optical inject signal. Similarly, optical-to-electrical patch panel device  110  may additionally include ports for monitoring either an electrical monitor signal or an optical monitor signal. For example, optical-to-electrical patch panel device  110  may have at least one of input-side optical inject signal port  288  for receiving input-side optical inject signal  245 , input-side optical monitor signal port  286  for transmitting input-side optical monitor signal  250 , input-side electrical inject signal port  285  for receiving input-side electrical inject signal  255 , and input-side electrical monitor signal port  284  for transmitting input-side electrical monitor signal  260 . 
         [0025]    In the normal mode of operation, input-side incoming optical signal  105  is received at input-side optical signal port  282  for optical-to-electrical conversion through optical-to-electrical patch panel device  110  and transmitted as input-side outgoing electrical signal  115  at input-side outgoing electrical signal port  280 . Specifically, input-side incoming optical signal  105  is received at input-side incoming optical signal port  282  of optical-to-electrical patch panel device  110 , transmitted through switch  210 , further transmitted through splitter  215 , further transmitted through optical-to-electrical signal converter  220 , further transmitted through switch  225 , and further transmitted to splitter  230 , before being transmitted out of optical-to-electrical patch panel device  110  through input-side outgoing electrical signal port  280  as input-side outgoing electrical signal  115 . 
         [0026]    Occasionally, there may be the need to inject an alternate electrical signal or an alternate optical signal and have it transmitted as input-side outgoing electrical signal  115 , instead of having input-side incoming optical signal  105  pass through as input-side outgoing electrical signal  115 . Where input-side optical inject signal  245  is received at input-side optical inject signal port  288 , a sensor  270  detects either the presence of input-side optical inject signal  245  or a connection at input-side optical inject signal port  288  and controls switch  210  so that the input-side optical inject signal  245  is transmitted through splitter  215 , instead of input-side incoming optical signal  105 , for optical-to-electrical conversion. Similarly, where input-side electrical inject signal  255  is received at input-side electrical inject signal port  285 , a sensor  265  detects either the presence of input-side electrical inject signal  255  or a connection at input-side electrical inject signal port  285  and controls switch  225  so that the input-side electrical inject signal  255  is transmitted through to splitter  230  instead of the converted input-side incoming optical signal received from optical-to-electrical converter  220 . 
         [0027]    It should be noted that switches  210  and  225  may be an optical switch or an electrical switch, respectively. Alternatively, switch  210  may be a combiner for combining input-side incoming optical signal  105  to be further transmitted to splitter  215 , such that when sensor  270  detects the presence of input-side optical inject signal  245  or a connection at input-side optical inject signal port  288 , the combiner is disabled, and instead, input-side optical inject signal  245  is combined to be further transmitted to splitter  215 . Similarly, switch  225  may be a combiner for combining converted input-side incoming optical signal from optical-to-electrical converter  220  to be further transmitted to splitter  230 , such that when sensor  265  detects the presence of input-side electrical inject signal  255  or a connection at input-side electrical inject signal port  285 , the combiner is disabled, and instead, input-side electrical inject signal  255  is combined to be further transmitted to splitter  230 . 
         [0028]    Sensors  265  and  270  may be any type of sensing devices, whether physical, mechanical, electrical, or optical, that are capable of detecting the connection of an input-side optical inject signal  245  at input-side optical inject signal port  288  or the connection of an input-side electrical inject signal  255  at input-side electrical inject signal port  285 . 
         [0029]    Occasionally, there may also be the need to monitor the input-side incoming optical signal  105 . In addition to transmitting input-side incoming optical signal through to optical-to-electrical signal converter  220 , splitter  215  may transmit input-side incoming optical signal as input-side optical monitor signal  250  through input-side optical monitor signal port  286 . Similarly, in addition to transmitting converted input-side incoming optical signal as input-side outgoing electrical signal  115 , splitter  230  may transmit converted input-side incoming optical signal as input-side electrical monitor signal  260  through input-side electrical monitor signal port  284 . 
         [0030]    Reference is next made to  FIG. 3  illustrating electrical-to-optical patch panel device  130  for use in switching system  100 . Electrical-to-optical patch panel device  130  is adapted to provide a signal converter, as well as signal injection and signal monitoring. It should be noted that electrical-to-optical patch panel device  130  does not necessarily have to be on the output-side of switch  120 , rather, electrical-to-optical patch panel device  130  may be any patch panel device adapted for electrical-to-optical signal conversion in a switching system. 
         [0031]    Electrical-to-optical patch panel device  130  has output-side incoming electrical signal port  380  for receiving output-side incoming electrical signal  125  and output-side outgoing optical signal port  382  for transmitting output-side outgoing optical signal  135 . 
         [0032]    Electrical-to-optical patch panel device  130  may additionally include ports for injecting either an electrical inject signal or an optical inject signal. Similarly, electrical-to-optical patch panel device  130  may additionally include ports for monitoring either an electrical monitor signal or an optical monitor signal. For example, electrical-to-optical patch panel device  130  may have at least one of output-side optical monitor signal port  388  for transmitting output-side optical monitor signal  360 , output-side optical inject signal port  386  for receiving output-side optical inject signal  355 , output-side electrical monitor signal port  385  for transmitting output-side electrical monitor signal  345 , and output-side electrical inject signal port  384  for receiving output-side electrical inject signal  340 . 
         [0033]    In the normal mode of operation, output-side incoming electrical signal  125  is received at output-side electrical signal port  380  for electrical-to-optical conversion through electrical-to-optical patch panel device  130  and transmitted as output-side outgoing optical signal  135  at output-side outgoing optical signal port  382 . Specifically, output-side incoming electrical signal  125  is received at output-side incoming electrical signal port  380  of electrical-to-optical patch panel device  130 , transmitted through switch  310 , further transmitted through splitter  315 , further transmitted through electrical-to-optical signal converter  320 , further transmitted through switch  325 , and further transmitted through splitter  330 , before being transmitted out of electrical-to-optical patch panel device  130  through output-side outgoing optical signal port  382  as output-side outgoing optical signal  135 . 
         [0034]    Occasionally, there may be the need to inject an alternate electrical signal or an alternate optical signal and have it transmitted as output-side outgoing optical signal  135 , instead of having output-side incoming electrical signal  125  pass through as output-side outgoing optical signal  135 . Where output-side electrical inject signal  340  is received at output-side electrical inject signal port  384 , a sensor  365  detects either the presence of output-side electrical inject signal  340  or a connection at output-side electrical inject signal port  384  and controls switch  310  so that the output-side electrical inject signal  340  is transmitted through splitter  315  instead of output-side incoming electrical signal  125 . Similarly, where output-side optical inject signal  355  is received at output-side optical inject signal port  386 , a sensor  370  detects the either the presence of output-side optical inject signal  355  or a connection at output-side optical inject signal port  386  and controls switch  325  so that the output-side optical inject signal  355  is transmitted through to splitter  330  instead of the converted output-side incoming electrical signal received from electrical-to-optical converter  320 . 
         [0035]    It should be noted that switches  310  and  325  may be an optical switch or an electrical switch, respectively. Alternatively, switch  310  may be a combiner for combining output-side incoming electrical signal  125  to be further transmitted to splitter  315 , such that when sensor  365  detects the presence of output-side electrical inject signal  340  or a connection at output-side electrical inject signal port  384 , the combiner is disabled, and instead, output-side electrical inject signal  340  is combined to be further transmitted to splitter  315 . Similarly, switch  325  may be a combiner for combining converted output-side incoming electrical signal from electrical-to-optical converter  320  to be further transmitted to splitter  330 , such that when sensor  370  detects the presence of output-side optical inject signal  355  or a connection at output-side optical inject signal port  386 , the combiner is disabled, and instead, output-side optical inject signal  355  is combined to be further transmitted to splitter  330 . 
         [0036]    Sensors  365  and  370  may be any type of sensing devices, whether physical, mechanical, electrical, or optical, that are capable of detecting the connection of an output-side electrical inject signal  340  at output-side electrical inject signal port  384  or the connection of an output-side optical inject signal  355  at output-side optical inject signal port  386 . 
         [0037]    Occasionally, there may be the need to monitor the output-side incoming electrical signal  125 . In addition to transmitting output-side incoming electrical signal through to electrical-to-optical signal converter  320 , splitter  315  may transmit output-side incoming electrical signal as output-side electrical monitor signal  345  through output-side electrical monitor signal port  385 . Similarly, in addition to transmitting converted output-side incoming electrical signal as output-side outgoing optical signal  135 , splitter  330  may transmit converted output-side incoming electrical signal as output-side optical monitor signal  360  through output-side optical monitor signal port  388 . 
         [0038]    Reference is next made to  FIG. 4 , showing cross-sectionally an incoming cable  402  and a cable receptacle  401  of an inject signal port of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  having light emitter  435  and light sensor  440  as sensors  265 ,  270 ,  365 , or  370 . 
         [0039]    On optical-to-electrical patch panel device  110 , cable receptacle  401  would be representative of input-side electrical inject signal port  285  or input-side optical inject signal port  288 . Accordingly, incoming cable  402  would be transmitting input-side electrical inject signal  255  or input-side optical inject signal  245 . 
         [0040]    On electrical-to-optical patch panel device  130 , cable receptacle  401  would be representative of output-side electrical inject signal port  384  or output-side optical inject signal port  386 . Accordingly, incoming cable  402  would be transmitting output-side electrical inject signal  340  or output-side optical inject signal  355 . 
         [0041]    Cable receptacle  401  is comprised of cable receptacle housing  405 , which houses cable receptacle fiber  415  for transmitting a signal. Cable receptacle adapter  410  is attached to the end of cable receptacle housing  405  for connection with incoming cable  402 . Similarly, incoming cable  402  is comprised of cable housing  425 , which houses cable fiber  430  for transmitting a signal. Cable adapter  420  is attached to the end of cable housing  425  for connection with cable receptacle  401 . Cable receptacle adapter  410  of cable receptacle  401  is adapted to accommodate the connection of cable adapter  420  of incoming cable  402  such that when the two parts are connected, cable receptacle fiber  415  is connected to cable fiber  430  allowing a signal from incoming cable  402  to be transmitted to cable receptacle  401 . 
         [0042]    In the illustrated embodiment, cable receptacle adapter  410  has a light emitter  435  and a light sensor  440  mounted on it. For example, light emitter  435  and light sensor  440  may be mounted on either sides of where cable fiber  430  of incoming cable  402  is to connect with cable receptacle  401 . Thus, when incoming cable  402  is not connected to cable receptacle  401 , the light sensor  440  detects the presence of light generated by light emitter  435 . However, when incoming cable  402  is connected to cable receptacle  401 , the light sensor  440  is not able to detect the presence of light generated by light emitter  435  because the light generated is broken by the connection of cable fiber  430  to cable receptacle fiber  415 . Accordingly, using this beam-break mechanism, the sensor  265 ,  270 ,  365 , or  370  of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  may be implemented. 
         [0043]    Reference is next made to  FIG. 5 , showing cross-sectionally an incoming cable  402  and a cable receptacle  401  of an inject signal port of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  having capacitance plates  505  and  510  as sensor  265 ,  270 ,  365 , or  370 . 
         [0044]    In the illustrated embodiment, cable receptacle adapter  410  has capacitance plates  505  and  510  mounted on it. For example, capacitance plates  505  and  510  may be mounted on either sides of where cable fiber  430  of incoming cable  402  is to connect with cable receptacle  401 . Thus, when incoming cable  402  is not connected to cable receptacle  401 , capacitance plates  505  and  510  maintain a certain charge between them. However, when incoming cable  402  is connected to cable receptacle  401  (i.e. the connection of cable fiber  430  to cable receptacle fiber  415 ), the capacitance between capacitance plates  505  and  510  change. Accordingly, using this capacitance-based mechanism, the sensor  265 ,  270 ,  365 , or  370  of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  may be implemented. 
         [0045]    Reference is next made to  FIG. 6A , showing cross-sectionally an incoming cable  402  and a cable receptacle  401  of an inject signal port of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  having a button  610  and a micro-switch  605  as the sensor  265 ,  270 ,  365 , or  370 . 
         [0046]    In the illustrated embodiment, cable receptacle adapter  410  has a button  610  mounted on micro-switch  605 . For example, button  610  and micro-switch  605  may be mounted on either sides of where cable fiber  430  of incoming cable  402  is to connect with cable receptacle  401 . Micro-switch  605  is capable of detecting very small movements. When incoming cable  402  is not connected to cable receptacle  401 , button  610  is in a normal position and does not exert any pressure on micro-switch  605 . However, when incoming cable  402  is connected to cable receptacle  401 , button  610  is depressed by the head of cable adapter  420  so that it pushes micro-switch  605 . Accordingly, using this micro-switch mechanism with a button  610 , the sensor  265 ,  270 ,  365 , or  370  of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  may be implemented. 
         [0047]    Reference is next made to  FIG. 6B , showing cross-sectionally an incoming cable  402  and a cable receptacle  401  of an inject signal port of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  having a pair of switch arms  620  and a micro-switch  615  as sensor  265 ,  270 ,  365 , or  370 . 
         [0048]    In the illustrated embodiment, the switch arms  620  are mounted on micro-switch  615 . For example, switch arms  620  and micro-switch  615  may be mounted on either sides of where cable fiber  430  of incoming cable  402  is to connect with cable receptacle  401 . In other embodiments only one switch arm may be provided. Micro-switch  615 , as with micro-switch  605  of  FIG. 6A , is capable of detecting very small movements. When incoming cable  402  is not connected to cable receptacle  401 , switch arms  620  are in a normal position indented inwards (towards the center of the cable receptacle) and do not exert any pressure on micro-switch  615 . However, when incoming cable  402  is connected to cable receptacle  401  (i.e. the connection of cable fiber  430  to cable receptacle fiber  415 ), switch arms  620  are pushed outwards against micro-switch  615 . Accordingly, using this micro-switch mechanism with switch arms  620 , sensor  265 ,  270 ,  365 , or  370  of either optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  may be implemented. 
         [0049]    Reference is next made to  FIG. 7 , showing the physical implementation of either the optical-to-electrical patch panel device  110  or the electrical-to-optical patch panel device  130 . Optical-to-electrical patch panel device  110  and electrical-to-optical patch panel device  130  are implemented such that they are hot-swappable in operation. 
         [0050]    In the illustrated embodiment, panel  750  is connected to an optical sub-assembly  701  and an electrical sub-assembly  703 . Optical sub-assembly  701  is comprised of optical cable receptacle base  745  connected to an optical cable receptacle  755  of optical cable  760 . Electrical sub-assembly  703  is comprised of electrical cable receptacle base  740  connected to an electrical cable receptacle  765  of electrical cable  770 . Electrical cable receptacle base  740  is also connected via electrical contacts  730  to electrical cable receptacle  725 . A printed circuit board (PCB)  705  housing optical-to-electrical patch panel device  110  or electrical-to-optical patch panel device  130  is comprised of at least an optical fiber cable connector  710  and electrical cable connector  716  having electrical contacts  715 . PCB  705  may additional comprise of a notch  720  for easy attachment to panel  750  and removal from panel  750 . 
         [0051]    In the normal mode of operation, optical fiber cable connector  710  of PCB  705  is connected to optical sub-assembly  701  of panel  750  while electrical cable connector  716  having electrical contacts  715  of PCB  705  is connected to electrical sub-assembly  703  of panel  750 . For example, in the optical-to-electrical patch panel device  110  of switching system  100 , optical cable  760  would receive input-side incoming optical signal  105  while electrical cable  770  would transmit input-side outgoing electrical signal  115 . Similarly, in the electrical-to-optical patch panel device  130  of switching system  100 , electrical cable  770  would receive output-side incoming electrical signal  125  while optical cable  760  would transmit output-side outgoing optical signal  135 . 
         [0052]    However, where there is a failure of the optical-to-electrical patch panel device  110  or of the electrical-to-optical patch panel device  130 , PCB  705  can be easily removed from panel  750  for the installation of a replacement PCB carrying either an optical-to-electrical patch panel device or electrical-to-optical patch panel device. 
         [0053]    While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.