Patent Document

PRIORITY CLAIM 
       [0001]    This application is a continuation-in-part of the application filed with the same name and inventor having Ser. No. 11/677,178, dated Nov. 12, 2012, itself claiming priority to the Provisional Application on file under Ser. No. 61/559,629 filed on Nov. 14, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    A configurable optical node, more specifically, a segmented bidirectional node is presented. 
       BACKGROUND OF THE INVENTION 
       [0003]    Cable Operators are continually seeking means to meet the demand placed upon them to provide consumers with more services such as video on demand, Internet access, and voice over internet services. Because the laying of fiber is one of the very high costs incumbent upon a provider, Operators strive to configure networks to satisfy the greatest number of customers through existing fiber by understanding that generally the customers have two distinct needs. First, there are needs for broadcast content such as network television contact where content sent in the forward direction is the same across a broad number of consumers. In the business, this is described as point-to-multipoint services. Generally broadcast services are both analog (extending from Channel 2 at (55 MHz) to Channel 79 (553 MHz)) and digital (extending up to, alternatively 650 MHz or 750 MHz depending upon system design parameters). 
         [0004]    For consumers there remains a second type of service known as narrowcast services such as Internet Access, telephony, or video on demand. For these services, known in the industry as multipoint-to-multipoint and carried on spectrum above that of broadcast services generally up to  1  GHz, content is unique on each path and there is no means by which to split and amplify a single signal to reach a large number of consumers. Rather each narrowcast signal is generally a single signal that reaches each consumer distinctly and generally is not split. Return path signals are a special case of narrowcasting in that they are unique signals from the consumer back up to the network headend. Return path signals include video on demand control signals, return Internet data, return telephony data. Return path signals are carried to the headend in frequency bands from 5 MHz to 40 MHz. 
         [0005]    Optical nodes facilitate the transmission of data in both directions by serving as the connecting device between the higher capacity fiber optic cable that extends from the headend down to the lower capacity coaxial cable that is generally used to connect individual consumers to the network and carries a signal in that part of the signal spectrum known as radio frequency or RF. In its simplest configuration a conventional optical node is said to be in 1×1 configuration when, it receives one set of downstream content from the headend and transmits just one set of upstream return path signals. (1×1 does not refer to the specific relation between numbers of RF ports used but only to the signal relationship between the node and the headend.) For example, in a broadcast forward mode, an optical signal might enter an optical node having four RF ports for output. In this example, the optical node is in  1 × 1  configuration meaning that the single downstream signal is split and amplified such that all four ports have the same downstream content and all upstream return signals are combined into a single upstream optical signal. If, in this example, the optical node services a community with 1000 consumer households, each RF port might, if the load was perfectly balanced, carry an RF signal sufficient to serve 250 homes. 
         [0006]    Distinct from a 1×1 configuration, a 4×4 configuration can be advantageous. As the name indicates the 4×4 optical node receives for forward distinct optical inputs and returns four distinct optical outputs to the headend. In this example, where four RF ports are present, the optical node converts the optical signals to four distinct electrical radio frequency (RF) signals, which it outputs each to one of the four ports. In essence, the system acts as four distinct optical to RF converters and in the reverse direction as RF to optical converts such that the signals inbound have a one to one relationship with the signals outbound. Thus, using a 4×4 optical node to transmit downstream may be costly in terms of fibers needed to service the network. 
         [0007]    Because broadcast service can be carried by fewer optical fibers to serve the same community than is required to service the same community with narrowcast service, operators have found that fully segmentable optical nodes (i.e. those that can be configured to either split or combine signals in traversing between optical and RF ports) have great utility in networks. Operators find it difficult and costly to obtain the rights to place a large number of optical nodes at ground level because, often, many other utility providers must compete for the same space. Thus segmented optical nodes are extremely attractive to operators. 
         [0008]    Without disturbing the basic fiber complement extending between a headend and the optical node, operators can install distinct configuration modules to distinctly task both optical interfaces and RF ports and can split signals as needed between them to create distinct configurations for both downstream and upstream signal transmission through the node. 
         [0009]    Making an optical node capable to serve several distinct segmentation schemes incorporates very distinct power and hardware requirements. A first basic segmentation scheme is known as a 2×2 requires that a second receiver and a second transmitter be installed in the optical node and a pair of two-way splitters is introduced to replace the four-way splitter between the original single receiver/transmitter and the four RF ports. 
         [0010]    In a second basic segmentation known as the 4×4 configuration discussed above, two receivers and two transmitters are added to the two existing receivers and two existing transmitters such that a set of four jumpers is introduced into the system to replace the previous splitter pairs. This 4×4 allows each of a receiver/transmitter pair within the optical node to be commissioned for dedicated service to each of the 4 RF output ports. 
         [0011]    Further complications result from the fact that traditional optical nodes rely on passive splitting for the 1×4 and 2×2 configurations, usually combined into a device often known as a configuration module. As these often passive configuration modules have different split losses, the node is designed such that an amplifier is added to supply enough gain between the receiver and RF output section (called a launch amplifier) to overcome the split loss of the 1×4 split. When configure to facilitate the 2×2 split, the optical node now provides excess gain available because exchanging the two-way splitter for the four-way splitter results a lower loss which designers typically address by introduction of a corresponding amount of fixed attenuation. Similarly the loss of splitters in a 4×4 configuration also requires addition of still further attenuation. One consequence of this process is that, as the number of receivers and transmitters increase, the node consumes proportionately more power. 
         [0012]    Unfortunately, as can readily be comprehended, each of these distinct modules with their distinct amplification and attenuation as employed in conventional optical node platforms must be separately designed and constructed. Further, the operator electing to reconfigure an optical node must also accommodate unique traffic management configurations, such as dedicating a receiver to 1 port or splitting 2 ports and dedicating a receiver each to the remaining 2 ports. So apart from requiring separate modules for splitting and amplification must also warehouse custom traffic modules. Individuals servicing the nodes are required to warehouse and keep a complete set of distinct modules on hand in order to configure each optical node as the need arises. 
         [0013]    What is needed in the art is a readily configurable optical node that allows configuration with a single configurable module which does not require either unnecessary amplification or power loss. 
       SUMMARY OF THE INVENTION 
       [0014]    A segmented optical node exploits a configuration module having arrayed all elements to go from a 1×4 to a 4×4 configuration, save optional redundant switches. A jumper board in the 1×, 2× path configures the node for 1×4 in one orientation and for 2×4 when flipped around 180 degrees. The 4×4 configuration is achieved by rotating the configuration module 90 degrees. In this orientation power to the module is also off, since the 4× configuration is passive. 
         [0015]    In its role managing amplification and splitting across the optical node, the configuration module is a “unity gain” device. That is, no matter what configuration, 1×4, 2×2, 4×4, or other, the gain of the module is zero dB. This means that the split loss is overcome in the module itself, and the path configurations are done by a means of an internal jumper board instead of by changing to a new module. In the 4×4 configuration, the module is simply rotated 90 degrees to completely remove power from the module while establishing the required 4 passive RF paths between each receiver and each launch amplifier port. 
         [0016]    Because of the unity gain across the module, the module allows conservation of power compared to all other segmentation designs. Because the configuration module is unity gain, the receiver and launch amplifier gain combined can be sized to provide 8 dB less than in a conventional design (8 dB is the rule-of-thumb split loss of a 4-way splitter). The conservation of amplification allows power saving opportunities in the receiver and launch amplifiers by the reduction of gain requirements in those sections. 
         [0017]    Further, the configuration module adds segmentation options that have been impractical to introduce into other node designs due to the need to offer such a large number of configuration board options. Those two additional options are 3+1 and 2+2. Additionally, trans-hinge coaxial cables enable a patch panel, allowing the individual servicing the optical node to configure the ports to manage traffic by simple cable arrangement. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    Preferred and alternative examples of the present invention are described in detail below with reference to the following drawings: 
           [0019]      FIG. 1  is a block diagram of an inventive optical node with configuration modules; 
           [0020]      FIG. 2  is a block diagram depicting the configuration module oriented in a socket at 0°; 
           [0021]      FIG. 3  is a block diagram depicting the configuration module oriented in a socket at 90°; 
           [0022]      FIG. 4  is a switching diagram depicting the configuration module in a 1×4 configuration with a single jumper board; 
           [0023]      FIG. 5  is a modification of the configuration module in a 1×4 with a single jumper board as shown in  FIG. 4  to include a redundant relay; 
           [0024]      FIG. 6  is a switching diagram depicting the configuration module in a 2×2 configuration with a single jumper board; 
           [0025]      FIG. 7  is a switching diagram depicting the configuration module in a 3+1 configuration with a single jumper board; 
           [0026]      FIG. 8  is a switching diagram depicting the configuration module in a 2+2 configuration with a single jumper board and a redundant relay; and 
           [0027]      FIGS. 9-14  depict various configurations of coaxial patch cords shown to balance traffic at optical transmitters in response to distinct traffic situations. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0028]      FIG. 1  is a block diagram of an inventive optical node  10  comprising three distinct and identifiable elements named for their distinct physical locations: a fiber tray  12 ; a lid  14  containing each of an inventive forward module  147  along with four optical to RF receivers  141  and an inventive reverse traffic manager module  145  and its four RF to optical transmitters  143 ; and a base  16  having four distinct launch amplifiers  161   a - d  and RF ports  163   a - d . Two additional hardline RF ports  165   a, b  are included for dedicated power entry but add no additional RF functionality. As set forth, these two hardline RF ports  165   a, b  allow for more flexibility in the placement of the power inserter wile alleviating power inserter insertion loss occasioned by relying upon the functional RF ports  163   a - d  for power insertion. Two power supplies  149   a, b  are present to condition power supplied to the forward  147  and reverse  145  configuration modules. 
         [0029]    The fiber tray  12  includes a series of optical connectors  129  for selectively connecting optical fiber to the fiber tray  12  for input and output of optical signals. The arrangement of connectors  129  with the reverse multiplexers  121 ,  123  and the forward multiplexers  125 ,  127  allow user configurable selection of optical connectors  129  for suitable configuration in any of the onboard multiplexers to facilitate several alternate configurations allowing the injection of optical signals in distinct configurations depending upon the needs of the operator. 
         [0030]    The lid  14  includes, as indicated above, four transmitters  143  and four receivers  141  which together serve as the interface between the optical fiber that ties the connectors  129  to the multiplexers  121 - 127  and on into the lid  14 . The reverse traffic manager module  145  presents the upstream signal to such of its four RF to optical transmitters  143  as it is configured to use to present to the reverse multiplexers  121 ,  123  for introduction into such fiber optic fibers as are connected to the connectors  129 . In a similar manner, downstream signals are received from the forward multiplexers  125 ,  127  at the receivers  147 . The forward multiplexers  125 ,  127  receive downstream signals through the connectors  129  to convey through such of the four optical to RF receivers  141  as the forward configuration module  147  tasks. Below the discussion moves to treat the operation of the forward  147  and the reverse  145  configuration modules in greater detail than in this overview of the system. 
         [0031]    A series of patch cords  15  are configurable to selectively connect the forward  147  and the reverse  145  configuration modules to the several launch amplifiers  161   a - d , through trans-hinge coaxial cables. The trans-hinge coaxial cables allow the user to intuitively connect output of the forward  147  and the reverse  145  configuration modules to such of four launch amplifiers  161   a - d  located in the base  16  according to the desired configuration. Simple columnar tables can be included within the base to facilitate the connections necessary. 
         [0032]    In the base  16 , four bidirectional launch amplifiers  161   a - d  are each arranged to condition the signals for the inbound and outbound signals through dedicated RF ports  163   a - d  coupled to each of the launch amplifiers  161   a - d . Because these are the principle power consumption devices within the optical node  10 , the arrangement of the launch amplifiers  161   a - d , within the base (in the presently preferred embodiment an aluminum casting having heat sink convection fins to dissipate heat generated in signal amplification). 
         [0033]    Referring to  FIG. 2 , the forward control module  147  (and similarly the reverse control module  145 ) provides conductivity paths or traces from the receivers  141   a - d  to the RF ports  163   a - d . Within the module  147 , a first set of four traces  1472  extends from a redundant switching section  1471  to a gain and split section  1473  to provide multiple switchably configurable unity gain paths through the module  147 . When the module  147  is oriented as depicted in  FIG. 2  a first set of pins  1475  engage the socket set  1479  on a base printed circuit board to provide switchably configurable set of four traces through the module  147  appropriate for any but the 4×4 configuration of the module (The 4×4 configuration being enabled by a purely unswitched path through the module (extending from a first set of pins  1477  to a second set of pins  1477 , shown) as discussed with reference to  FIG. 3  below). In such a manner, the physical configuration of the module  147  with the two sets of pins  1475  and  1477  and two sets of traces connecting those pins are two means to configure the module to present unity gain across the module  147  for each of the configurations in which the module splits and combines signals across the module  147 . A user achieves further configuration of the fully configurable module by use of the jumper switch and the gain and split section  1473  as discussed in greater detail below. 
         [0034]    In contrast, when oriented as depicted in  FIG. 3 , a second set of pins  1477  engage the socket  1479  which then connect a second set of traces  1476  for a purely passive path from the first set of pins  1477  to the second set of pins  1477  with no switching capacity needed. As these traces are simple straight and nowhere split along the module  147 , they have no need for amplification to make up splitting losses. For that reason, when the orientation of the module is rotated as depicted in  FIG. 3  unity gain simply describes conductivity along these traces  1476 . 
         [0035]    The further innovation that is a key to the versatility of the configuration module is depicted in  FIGS. 4-8 . By judicious selection and geometric configuration of several elemental components, specifically three splitters  14731   a - c , two amplifiers  14732   a, b  (selected to impart gain selected to exactly balance splitter losses), and two redundant relays  14733   a, b , the configuration module can be configured to allow for four distinct configurations in response to positions of a single jumper switch having three positions. The positions for the jumper switch are “1×4”, “3+1”, “2×2” and “2+2”. When the control module configuration module oriented in the socket at 0°, this switch enables tailoring of the module for any of these three modes and with jumper settings, the presence of the redundant relays allows exploitation of second receivers as backups to first receivers providing a failover capacity in the optical node. 
         [0036]    By way of overview, each of the several configurations enabled by exploiting a discipline imparted by designing conductivity paths with a unity gain is reviewed in turn. It is an important feature of the configuration block  147  that each configuration, in turn, is achieved by switching the jumper switch and selective connection of components in accord with the switch position. Thus, without other physical change to the configuration block  147 , the block yields each of the following configurations:  FIG. 4  is a switching diagram depicting the configuration module in a 1×4 configuration with a single jumper board;  FIG. 5  is a modification of the configuration module in a 1×4 with a single jumper board as shown in  FIG. 4  to include a redundant relay;  FIG. 6  is a switching diagram depicting the configuration module in a 2×2 configuration with a single jumper board;  FIG. 7  is a switching diagram depicting the configuration module in a 3+1 configuration with a single jumper board; and  FIG. 8  is a switching diagram depicting the configuration module in a 2+2 configuration with a single jumper board and a redundant relay. 
         [0037]    As is stated above, the user readily configures the module  147  by simply moving the switch from position to position thereby changing the conductive path through the module  147  and its eight elemental components. In this description, only the receiver and forward direction are described. The selection of the forward direction is not meant to limit the configuration block to a single direction. Indeed, the strength of the invention, lies, in part, to its “commutative” nature in that every configuration performed using amplifiers and splitters for forward reception can and is duplicated in the reverse direction for transmission. That the explanation is limited to a single direction is simply that such an explanation is deemed to be adequate to a person having ordinary skill in the art. In a configuration block conforming to the invention it is desirable that both paths are likewise modified by a single movement of the jumper switch or a single change in orientation and in the presently preferred embodiment, both paths are present in a single configuration block though even that is not necessary to practice the invention. 
         [0038]    In  FIG. 4 , the 1×4 forward configuration with no segmentation, wherein one receiver is used. The receiver converts forward optical signal and routes it to the forward configuration module. The forward configuration module then splits the signals into four path and distributes them to each of the four active output ports. As is evident in  FIG. 4 , the jumper switch is in a first position, specifically the “1×4” position. Once the configuration block  147  is placed in the “1×4” position, a technician connects only one of the four receivers  141   a - d , specifically the first receiver  141   a,  with the first amplifier  14732   a  and because there is only one, no redundancy is available.  FIG. 5  shows the same configuration with the addition of a relay  14733   a  and the addition of a second receiver  141   c  to allow remote switching in the case of an outage of the first receiver  141   a.    
         [0039]    In each of the configurations of the configuration block  147 , the conductors are switched to form a path extending from the first and the second amplifiers  14732   a, b  which are each configured to amplify the input two-fold to yield an intermediate gain of four times that of the output of receiver  141   a.  By switching the two amplifiers to perform in series, unity gain at the output is maintains as the four-fold amplifications to counters the diminution of the signal by the workings of a four-way split of the signal downstream within the block. A first two-for-one splitting occurs at the splitter  14731   c.  The output of that splitter is, in turn, split two-for-one at each of a second and a third splitter  14731   a  and  14733   b  thereby quartering the amplitude conveying the output signal at unity gain relative to the inputs to each of four RF ports. 
         [0040]    As stated above, the configuration depicted in  FIG. 4  is the same as  FIG. 5  except for the relay. In the 1×4 forward configuration with redundancy, one more receiver provides greater reliability increasing the time between maintenance actions. Under normal operation condition, the signal flow is identical to the basic 1×4 forward configuration and the secondary receiver remains as a backup. If the optical power of the primary receivers is below optical power threshold (which can be set by user), it is automatically shut down and the signal is routed to the redundant receiver. The redundant receiver functions the same way the primary receiver does, and when the optical power rises back to suitable levels, the primary receivers  141   a, c  are reactivated while the back-ups receiver is shut down. 
         [0041]    With the block  147  in 1×4 configuration, the one of the receivers  141   a, b  converts the optical input signals to RF signals and then routes them through the forward configuration module. Each signal is amplified by one of the two respective amplifiers  14732   a, b , acting in series to amplify the signal one and again by a factor of two. In either of the configurations depicted in  FIGS. 4 and 5 , showing the configuration block  147 , the conductors are switched to form a path extending from the first and the second amplifiers  14732   a, b  to yield an intermediate gain of four times that of the output of receiver  141   a . By placing the two amplifiers in series, unity gain at the outputs is maintained as the four-fold amplifications simply counters the diminution of the signal by the workings of a four-way split of the signal downstream within the block. A first two-for-one splitting occurs at the splitter  14731   c.  The output of that splitter is, in turn, split two-for-one at each of a second and a third splitter  14731   a  and  14733   b  thereby quartering the intermediate amplitude conveying the output signal at unity gain relative to the inputs to each of four RF ports. 
         [0042]    In  FIG. 6 , the configuration block is set, as is apparent, in 2×2 forward segmentation, two of the forward receivers  141   a, c  are used as primary receivers while each of two forward receivers  141   b, d  wait behind relays  14733   a, b  to be activated when necessary as described above in the reference to  FIG. 5 . Realizing that the placement of the relays and the second receivers  141   c  and  141   d  to provide redundancy is not necessary for the practice of the invention, the redundancy feature will no longer be repeatedly qualified as an option. In spite of the desirability of redundancy, the invention, as invention, does not require redundant relays and back-up receivers or transmitters to exploit the jumper configurable configuration block and their addition or absence should not be viewed as necessary to practice the invention. 
         [0043]    As is the case in the 2×2 configuration the switch in  FIG. 6  indicates, each receiver  141   a, b  (or individually, as needed, each of their back-up receivers  141   c, d  as explained above) is dedicated to two output ports (the first receiver  141   a  to  163   a  and  163   c  and the second receiver  141   b  to ports  163   b  and  d ). Upon exiting each of their respective relays,  14733   a, b  each of the corresponding amplifiers  14732   a, b  amplifies the signal by a factor of two and, at corresponding splitters  14731   a, b , the signals are then split into two paths and distributed to each of two of the output ports  163   a - d  for each of the two receivers  141   a, b  at an overall unity gain. 
         [0044]    Referring now to  FIG. 7 , the configuration block  147  has been switched into 3+1 Forward Segmentation mode and is shown in a mode with optional redundancy, as explained above. In 2×2 forward segmentation with redundancy, as shown in  FIG. 6 , four forward receivers  141   a - d  are used to supply four ports  163   a - d . In the 3+1 mode, two receivers  141   c  and  141   d  (changed, in this part of the discussion from  141   a  and  141   b  to demonstrate the versatility of the inventive configuration block) will supply four output ports. The correspondence, however, is very different. In 3+1 mode, each of the primary receivers  141   c, d  are paired with corresponding back-up receivers  141   a, b  and one pair, primary  141   a  and backup receivers  141   c  is dedicated to three output ports  163   a - c , while the remaining pair  141   b, d  is dedicated to the last port. (Usually, the one port with the most traffic load.) Also as above, under normal operation condition, the signal flow is identical to 3+1 without the redundancy afforded by the relays  14733   a, b  allowing, in each pair, one of the receivers  141   a, b  to remain dormant as a backup. Again, if the optical power of one of the primary receivers is below optical power threshold (which can be set by user), the receiver is shut down and the signals are routed to the corresponding redundant receiver. These redundant receivers function the same way the primary receivers do, and when the optical power risks pass, the primary receivers are reactivated while the back-ups are shut down. 
         [0045]    Unlike the previously discussed configurations of the configuration block, to achieve unity gain, attenuation gain within the block  147  occasioned by the presence and operation of unpaired splitters, is accomplished by the introduction of two components not operational in the previously discussed configurations. In the 3+1 configuration of the block  147 , the output of the first amplifier  14732   a  is fed to the first splitter  14731   c.  While one side of the output of the first splitter  14731   c  is fed to the second splitter  14731   a , just as in the previously discussed configurations, the second side is fed to a pass-through  151  that attenuates the signal by half, thereby providing the RF port 2,  163   b  with a signal having unity gain. An attenuator is an electronic device that reduces the power of a signal without appreciably distorting its waveform. An attenuator is effectively the opposite of an amplifier, though the two work by different methods. While an amplifier provides gain, an attenuator provides loss, or gain less than 1. 
         [0046]    The pass through functions as an attenuator. Attenuators are usually passive devices made from simple voltage divider networks. Switching between different resistances forms adjustable stepped attenuators and continuously adjustable ones using potentiometers. For higher frequencies precisely matched low voltage standing wave ratio or VSWR resistance networks are used. Fixed attenuators in circuits are used to lower voltage, dissipate power, and to improve impedance matching. In measuring signals, attenuator pads or adaptors are used to lower the amplitude of the signal a known amount to enable measurements, or to protect the measuring device from signal levels that might damage it. Attenuators are also used to ‘match’ impedances by lowering apparent standing wave ratio or SWR. 
         [0047]    In an extreme embodiment of an attenuator, a signal or RF trap, dissipates radio frequency energy to eliminate stray currents within the configuration block. All RF energy fed to the signal trap must be dissipated at least within operating frequencies, or it will degrade performance within the configuration block  147 . The signal trap  153  performs this attenuation and dissipation of RF energy for the configuration block  147 . 
         [0048]    With reference to the output of receivers  2  and  4 ,  141   b  and  d  respectively, the path is identical to that portrayed in either of  FIGS. 4 and 5  except that the first output of the third splitter  14731   b  that is depicted as flowing into RF port 2  163   b  is receiving the output from the pass-through attenuator  151  which attenuates the input signal received at RF port 1  163   b  by one half, just as the interposition of a splitter would have done in the same position as the pass through attenuator  151 . Just as in the prior configurations of the block  147 , the gain across the block at any of the ports remains at unity. 
         [0049]    Similarly, the output of the second splitter  14731   b  is passed, on the first leg to the fourth port  163   d  which receives one half of the RF energy that had been received at the splitter  14731   b  input. The other half of the RF energy now is fed into a signal trap  153  that completely attenuates the energy as discussed above and, thus, the signal at RF port 4  163   d  arrives with the same unity gain as at its three sisters, ports 1-3  163   a - c.    
         [0050]    In the penultimate description, in  FIG. 8 , the 2+2 configuration of the configuration block  147  is depicted. In the 2+2 forward segmentation configuration, 3 forward receivers  141   a, b, d  are used. One receiver  141   a  (and its redundant back up  141   c  through the relay  14733   a ) is dedicated to two of the output ports  163   a, c  while each of the remaining two receivers  141   b, d  are each dedicated to a single output port  163   b  and  d  respectively. One signal path from the first receiver  141   a  is amplified at the amplifier  14732   a  and split into two paths at the splitter  14731   a  and distributed to two output ports  163   a, c , while the remaining two signal paths emanating from two receivers  141   b, d  are directly routed to the remaining two ports  163   b, d  individually. Such a configuration is used in the case of heavy traffic loads on two of the four ports  163   b, d.    
         [0051]    It is worth noting, at this juncture, there are no physical switches except the configuration switch. In the presently preferred embodiment, positions of the configuration switch selectively activate transistors to provide the actual switching function that the connections portrayed in these drawings. While a physical switch could be used, the present invention can be enabled by either electronic switching or physical switching, but in this depiction the physical switch is used as a valid analogy to portray movement of the signal through the module  147 . 
         [0052]      FIGS. 10 through 17  depict various patching arrangements that are possible with the coaxial cords used to place the output from the receivers suitably at the inputs of the bidirectional launch amplifiers. Depicted in each is a block diagram of the base  16  having four launch amplifiers  161   a - d  and four corresponding RF ports  163   a - d . Each of the four launch amplifiers  161   a - d  are bidirectional and will amplify a signal coming upstream or flowing down with a suitable input or output for each as appropriate. Importantly, for clarity, the configuration modules have been removed from the paths for illustrative purposes. To function as discussed herein, however, the configuration modules must be present. 
         [0053]    In each of the several depictions, a series of four coaxial jumper cables is shown acting as “patch cords.” A patch cable or patch cord connects (“patches-in”) one electronic device to another for signal routing. Generally, as here, patch cords are used to connect devices of different types (e.g., a switch connected to a computer, or a switch to a router). While the patch cords are numbered  151 ,  152 ,  153 , and  154 , this convention is not meant to suggest that the patch cords, as numbered, are the same cords from figure to figure. Rather, they are numbered simply to locate them for the reader in each of the distinct drawings. The use of all other reference numbers herein are according to the standard convention of identifying the component uniquely and consistently from one figure to the next. 
         [0054]    In  FIG. 9 , two of the four receivers, the first receiver  141   a  and the third receiver  141   c , are depicted as connected to individual launch amplifiers  161   a - d , likely to show a broadcast configuration of the device as well as its flexibility. In this example, the north RF ports  163   a, c  are experiencing heavy traffic. Assuming that this load is based upon a relatively stable demand such that it is advantageous to configure the optical node to address this demand. An operator can then split the heavier load between two receivers rather than to assign one to the two RF ports  163   a, c , bearing the heavier traffic and one to those ports  163   b, d , bearing the lighter traffic. Thus, an operator would want, optimally, to take the output of Receiver 1 and split it between a heavy and a medium traffic port such as RF ports  1  and  2 ,  163   a  and  163   b.  Thus, the operator will connect Receiver  1   141   a  to the RF ports  1  and  2 ,  163   a, b , with coaxial cable patch cords  151  and  153  at the launch amplifiers on the downstream side  161   ar  and  161   br  respectively. In a similar manner, Receiver  3 ,  141   c  will send its output through patch cords  152  and  154  to the downstream side of launch amplifiers  161   dr  and  161   cr  respectively. Hence,  FIG. 8  depicts the use of the patch cords to suitably address long-term changes in traffic. 
         [0055]      FIG. 10  portrays the upstream configuration of the same traffic issues as  FIG. 8  portrays. Once again, heavy traffic on RF ports 1 and 3,  161   a  and  161   c,  dictates a need to balance load as between transmitters 1 and 3,  143   a,  and  143   c.  To that end, coaxial cables  151  and  153  connect transmitter 1 to each of launch amplifiers  161   ar  and  br  on the upstream side. Again, the transmitter 3 is connected to the upstream sides of launch amplifiers at  161   ct  and  dt  using patch cords  152  and  154  respectively. In this manner, the load on either transmitter  143   a  and  143   c  is balanced relative to the other. 
         [0056]      FIG. 11  shows a situation nearly identical configuration but configured as the coaxial cable is, to split the load between heavy traffic and regular traffic, the split is shown to be advantageous when demand shifts. As can be appreciated, when the heavy traffic has shifted from RF Port 1  163   a  to RF Port 2  163   c  and likewise from RF Port 3  163   b  to RF Port 4  163   d,  the exact same coaxial configuration continues to allow a balanced traffic between Transmitter 1  143   a  and Transmitter 3  143   c.  Given these two depicted examples, one can easily see how even shifting loads can be accommodated by judicious selection of correspondence between transmitters and RF ports. 
         [0057]      FIG. 12  shows that traffic has moved to a region that had, in  FIGS. 10 and 11  had been served by Transmitter 3 alone. A simple exchanging of the patch cords  151  and as they are connect to input ports  161   bt  and  161   ct  results in the configuration shown in  FIG. 12 , thereby returning the balance of traffic as between Transmitter 1  143   a  and Transmitter 3  143   c.  Clearly any service interruption necessitated by the exchange of the patch cords  152  and  153  will be minimal given the highly intuitive and extremely simple procedure the patch cord arrangement facilitates. 
         [0058]    Thus far, we have discussed balanced shifting of traffic such that pairs of ports are experiencing increased or diminished demand. In  FIG. 13  a different situation. As discussed in reference to  FIGS. 4-8 , the configuration module  147  can be configured to a “3+1” configuration just as it can also be configured to a “1×1” with redundancy. Assuming that a service person has suitably adjusted the jumper switches as they are labeled, the output of Transmitter 3,  141   c  can be dedicated to a single RF port (RF Port 4  163   d  as illustrated) in response to heavy traffic on that single port. The remaining ports can be serviced by the single Transmitter 1 in “3+1” configuration. Coaxial patch cords  151 ,  152 , and  153  connect RF Ports 1, 2, and 3  163   a - c , respectively, to, suitably, balance the traffic between the transmitters. 
         [0059]    Again,  FIG. 14  demonstrates the versatility of the configuration node  10  as traffic loads shift. In this example, the heavy traffic has shifted from RF port 4  163   d  to RF port 3  163   c.  Simple exchange of terminal ends of patch cords  152  and  154  results in dedication of Transmitter 3 to the heavy traffic on RF port 3  163   c.    
         [0060]    While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. For example, patch cords may be configured to meet other needs according to the earlier explanation. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.

Technology Category: h