Patent Publication Number: US-6905363-B2

Title: Cross-connect jumper assembly having tracer lamp

Description:
This application is a continuation of U.S. patent application Ser. No. 10/219,809, filed Aug. 14, 2002, and issued as U.S. Pat. No. 6,743,044. U.S. patent application Ser. No. 10/219,809 is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The present invention relates generally to digital cross-connect equipment. More particularly, the present invention relates to cross-connect switching systems having tracer lamp circuits. 
   BACKGROUND OF THE INVENTION 
   In the telecommunications industry, the use of switching jacks to perform digital cross-connect (DSX) and monitoring functions is well known. The jacks may be mounted to replaceable cards or modules, which in turn may be mounted in a chassis, and multiple chassis may be mounted together in an equipment rack. Modules for use in co-axial environments are described in U.S. Pat. No. 5,913,701, which is incorporated herein by reference. Modules for use in twisted pair applications are described in U.S. Pat. No. 6,116,961. Cross-connect modules are also used with fiber optic communications systems. 
     FIG. 1  shows a prior art cross-connect arrangement of the type used for co-axial applications. The depicted arrangement includes two jack modules  20 ,  22 . The jack modules  20 ,  22  may be mounted in separate chassis that are in turn mounted on separate racks. Each jack module  20 ,  22  is cabled to a separate network element (i.e., piece of telecommunications equipment). For example, jack module  20  is connected to equipment  24  by cables  26 , and jack module  22  is connected to equipment  28  by cables  30 . The pieces of equipment  24  and  28  are interconnected by cross-connect jumpers  32  (e.g., cables) placed between the two jack modules  20  and  22 . Each jack module  20 ,  22  includes IN and OUT ports  34  and  36  for direct access to the equipment&#39;s input and output signals. Each module  20 ,  22  also includes X-IN and X-OUT ports  35 ,  37  for providing direct access to the cross-connect input and cross-connect output signals. Ports  34 - 37  provide a means to temporarily break the connection between the pieces of equipment  24  and  28  that are cross-connected together, and to allow access to the signals for test and patching operations. The jack modules  20 ,  22  also include monitor ports  38  for non-intrusive access to the input and output signals of each piece of telecommunications equipment  24 ,  28 . 
   A typical telecommunications central office includes many jack modules and a large number of bundled cables interconnecting the modules. Consequently, absent indicators, it is difficult to quickly determine which two jack modules are cross-connected together. To assist in this function, the jack modules  20 ,  22  include indicator lights  40  wired to power  42  and ground  44 . Switches  46  are positioned between the indicator lights  40  and ground  44 . The indicator lights  40  are also electrically connected to pin jacks  48  located at the rear of the jack modules  20 ,  22 . The pin jacks  48  provide connection locations for allowing the tracer lamp circuits corresponding to each of the modules  20 ,  22  to be interconnected by a messenger wire  50 . The messenger wire  50  is typically bundled with the jumpers  32  to form a cross-connect jumper assembly. When either switch  46  is closed, the indicator lamps  40  corresponding to both of the jack modules  20   22  are connected to ground and thereby illuminated. Thus, by closing one of the switches  46 , the two jack modules  20 ,  22  that are cross-connected can be easily identified by merely locating the illuminated tracer lamps. 
   A problem with tracer lamp configurations as described above is that they are only visible from the front ends of the jack modules. Thus, a technician at the rear of the modules is required to walk around to the front to view the tracer lamps. 
   SUMMARY 
   The present disclosure describes representative embodiments that relate generally to DSX jumper assemblies having integral tracer lamps. The present disclosure also describes digital cross-connect LED circuitry that illuminates regardless of the direction of current travel. It will be appreciated that the various inventive aspects disclosed herein can be used together or separately from one another. It will further be appreciated that the disclosed examples are merely illustrative, and that variations can be made with respect to the depicted examples without departing from the broad scope of the inventive concepts. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate various embodiments that are examples of how certain inventions can be put into practice. A brief description of the drawings is as follows: 
       FIG. 1  illustrates a prior art DSX system; 
       FIG. 2  illustrates a DSX system including a jumper assembly that is an example of how certain inventive aspects in accordance with the principles of the present invention may be practiced, the jumper assembly includes a messenger wire with integral tracer lamps; 
       FIG. 3  is a schematic diagram of the DSX system of  FIG. 2 ; 
       FIG. 4  shows the jumper assembly of  FIG. 2  in isolation from the remainder of the DSX system; 
       FIG. 5  is a schematic diagram of the jumper assembly of  FIG. 4 ; 
       FIG. 6  is a schematic diagram illustrating current flow through the messenger wire of the jumper assembly when the switch of a left tracer lamp circuit is activated; 
       FIG. 7  is a schematic diagram illustrating current flow through the messenger wire of the jumper assembly when the switch of a right tracer lamp circuit is activated; 
       FIG. 8  is an exploded, perspective view of one of the tracer lamps that is integral with the messenger wire of the jumper assembly of  FIGS. 4 and 5 ; 
       FIG. 9  is a cross-sectional view of the tracer lamp of  FIG. 6  as assembled; 
       FIG. 10  illustrates an alternative tracer lamp configuration that is an example of how certain inventive concepts in accordance with the principles of the present disclosure can be practiced; 
       FIG. 11  illustrates another tracer lamp configuration that is an example of how certain inventive aspects in accordance with the principles of the present disclosure can be practiced; 
       FIG. 12  illustrates a further tracer lamp configuration that is an example of how certain inventive aspects in accordance with the principles of the present disclosure can be practiced; 
       FIG. 13  is a schematic diagram of another jumper assembly configuration that is an example of how certain inventive aspects in accordance with the principles of the present disclosure can be practiced; 
       FIG. 14  is a schematic diagram of a further jumper assembly configuration that is an example of how certain inventive aspects in accordance with the principles of the present disclosure may be practiced; 
       FIG. 15  is an exploded view of an example tracer lamp configuration adapted for use with the jumper assembly of  FIG. 14 ; and 
       FIG. 16  is an assembled, cross-sectional view of the tracer lamp configuration of FIG.  15 . 
   

   DETAILED DESCRIPTION 
     FIG. 2  illustrates a digital cross-connect (DSX) system  120  that is an example of how certain inventive aspects in accordance with the principles of the present disclosure can be practiced. The DSX system  120  includes DSX modules  122   a ,  122   b  electrically connected to pieces of telecommunications equipment  123   a ,  123   b  by cables  125   a ,  125   b  (e.g., co-axial cables). The pieces of telecommunications equipment  123   a ,  123   b  are electrically connected to one another by a jumper assembly  124  that provides a cross-connection between the DSX modules  122   a ,  122   b . The DSX modules  122   a ,  122   b  include tracer lamps (e.g., LED&#39;s  150   a ,  150   b ) that are visible from front ends of the modules  122   a ,  122   b . The jumper assembly  124  includes tracer lamp assemblies  134   a ,  134   b  that are visible from rear ends of the modules  122   a ,  122   b.    
   Referring to  FIGS. 2 and 3 , the DSX modules  122   a ,  122   b  include IN switching jacks  144   a ,  144   b  and OUT switching jacks  146   a ,  146   b  that provide a means for temporarily breaking the cross-connections between the pieces of telecommunications equipment  123   a ,  123   b  to allow access to the IN and OUT signals for test and patching operations. As is conventionally known in the art, the switching jacks include ports for receiving plugs used to access the IN and OUT signals. The switching jacks also include switches for temporarily breaking the cross-connections when the plugs are inserted within the ports for test and patching operations. In a preferred embodiment, the switches can be make-before-break switches. The DSX modules also include monitor networks  147   a ,  147   b  (shown in  FIG. 3 ) for allowing signals to be non-intrusively monitored. Example switching jacks are also disclosed in U.S. Pat. Nos. 4,749,968 and 5,913,701, which are hereby incorporated by reference in their entireties. 
   Referring to  FIGS. 2 and 4 , the jumper assembly  124  of the cross-connect system  120  includes two jumper cables  126  and  128  (i.e., cross-connect cables) and a messenger wire  130 . As used herein, the term “messenger wire” includes any elongate electrically conductive member. In one embodiment, the messenger wire is a copper wire. The jumper cables  126 ,  128  and the messenger wire  130  are bundled together by a sheath  132  to form the jumper assembly  124 . Alternatively, the messenger wire  130  can be secured to the cables  126 ,  128  by any number of different techniques such as tying, binding, strapping, etc. In other embodiments, the messenger wire  130  can be separate/separable from the jumper cables  126 ,  128 . The tracer lamp assemblies  134   a ,  134   b  are carried with the messenger wire  130 . For example, in one embodiment, the tracer lamp assemblies  134   a ,  134   b  are mounted at opposite ends of the messenger wire  130 . In other embodiments, lamp assemblies can be mounted at other locations along the length of the wire  130 . 
   The jumper cables  126 ,  128  of the jumper assembly  124  are electrically coupled to rear ends of the modules  122   a ,  122   b  by connecters such as conventional co-axial connectors  127   a ,  127   b  (e.g., Bayonet Normalized Connectors (BNC), Threaded Normalized Connectors (TNC), 1.6/5.6 style connects, etc.). Similar connectors can be used to connect the cables  125   a ,  125   b  to the rear ends of the modules  122   a ,  122   b.    
   As shown in  FIG. 3 , the modules  122   a ,  122   b  include tracer lamp circuits  121   a ,  121   b . The tracer lamp circuits  121   a ,  121   b  include tracer lamps (e.g., the front LED&#39;s  150   a ,  150   b ). The LED&#39;s  150   a ,  150   b  are wired to power source contacts  152   a ,  152   b  and to ground contacts  154   a ,  154   b . Switches  156   a ,  156   b  are positioned between the LED&#39;s  150   a ,  150   b  and their corresponding ground contacts  154   a ,  154   b . The switches  156   a ,  156   b  allow the LED&#39;s  150   a ,  150   b  to be selectively connected to and disconnected from their corresponding ground contacts  154   a ,  154   b.    
   The messenger wire  130  of the jumper assembly  124  electrically connects the tracer lamp circuits  121   a ,  121   b  together. In the depicted embodiment, pin jacks  160   a ,  160   b  provide connection locations for electrically connecting the messenger wire  130  to the tracer lamp circuits  121   a ,  121   b . The pin jacks  160   a ,  160   b  include sockets for receiving conductive pins  170   a ,  170   b  (best shown in  FIG. 4 ) coupled to the messenger wire  130 . When either of the switches  156   a ,  156   b  is closed, the connection provided by the messenger wire  130  causes both the LED&#39;s  150   a ,  150   b  to be illuminated. For clarity, the wires connecting the switch  156   a , the LED  150   a , the power contact  152   a , the ground contact  154   a  and the pin jack  160   a  are not shown in FIG.  2 . The wires are schematically depicted in FIG.  3 . 
   As indicated previously, the tracer lamp assemblies  134   a ,  134   b  are located at opposite ends of the messenger wire  130  (see FIG.  4 ). The assemblies include translucent housings  172   a ,  172   b  from which the conductive pins  170   a ,  170   b  project. The tracer lamp assemblies  134   a ,  134   b  also include structure for illuminating the housings  172   a ,  172   b . For example, referring to  FIG. 5 , LED&#39;s  174   a ,  174   b  are mounted within each of the housings  172   a    172   b . The LED&#39;s  174   a ,  174   b  can include conventional flasher circuitry for causing the LED&#39;s  174   a ,  174   b  to flash for a predetermined length of time when activated and then turn to steady-on. In other embodiments, steady-on LED&#39;s can also be used without using flashing circuitry. The tracer lamp assemblies  134   a ,  134   b  also include resistors  178   a ,  178   b  positioned in series with the LED&#39;s  174   a ,  174   b . Illumination devices (e.g., lamps) other than LED&#39;s could also be used. 
   It is well known that electrical current can only pass through a diode in one direction. In the drawings, this direction is indicated by the direction of the schematic diode arrows. Current flowing in a direction opposite to the diode arrows will be blocked from passing through the diodes. When current flows through a light emitting diode (LED), the LED is illuminated. 
   It is advantageous for the LED&#39;s  174   a ,  174   b  to illuminate regardless of the direction that current flows through the messenger wire  130 . To ensure that current will flow to the LED&#39;s  174   a ,  174   b  in the direction of the LED diode arrows regardless of the direction that current flows through the messenger wire  130 , the tracer lamp assemblies  134   a ,  134   b  include rectifier circuits  180   a ,  180   b  (see FIG.  5 ). The rectifier circuits  180   a ,  180   b  each include four diodes  181   a - 184   a  and  181   b - 184   b . The rectifier circuits  180   a ,  180   b  route current flow so that it passes through the LED&#39;s  174   a ,  174   b  in the proper illumination direction regardless of whether the current is flowing through the messenger wire  130  from the tracer lamp circuit  121   a  to the tracer lamp circuit  121   b , or from the tracer lamp circuit  121   b  to the tracer lamp circuit  121   a . For example, when switch  156   a  is closed such that current flows through the messenger wire  130  from the tracer lamp circuit  121   a  to the tracer lamp circuit  121   b , the rectifier circuits  180   a ,  180   b  cause both LED&#39;s  174   a ,  174   b  to be illuminated (see  FIG. 6  where arrows have been added to show the direction of electrical current flow). Similarly, when switch  156   b  is closed such that current flows through the messenger wire  130  from the tracer lamp circuit  121   b  to the tracer lamp circuit  121   a , the rectifier circuits  180   a ,  180   b  cause both LED&#39;s  174   a ,  174   b  to be illuminated (see  FIG. 7  where arrows have been added to show the direction of electrical current flow). As is apparent from  FIGS. 6 and 7 , the LED&#39;s  150   a ,  150   b  as well as the LED&#39;s  174   a ,  174   b  illuminate whenever either of the switches  158   a ,  158   b  are closed. 
     FIG. 8  is an exploded view of the tracer lamp assembly  134   a . It will be appreciated that the tracer lamp assembly  134   b  has an identical configuration. Thus, only the tracer lamp assembly  134   a  will be described. 
   As shown in  FIG. 8 , the housing  172   a  of the tracer lamp assembly  134   a  has a two-piece configuration including a main housing piece  202  and a housing cap  203 . The housing  172   a  is sized to hold a number of tracer lamp components such as the conductive pin  170   a , a circuit board assembly  250 , and a double-crimp conductor  270 . The housing  172   a  is preferably made of a translucent material such as translucent plastic. In certain embodiments, the housing  172   a  can be transparent, opaque or tinted with a color (e.g., red, yellow, amber, blue, green, etc.). 
   The main housing piece  202  of the housing  172   a  has a hollow, cylindrical configuration and includes a first end  204  positioned opposite from a second end  206 . An annular, outer retaining shoulder  208  is located adjacent the second end  206 . An inner, annular retaining shoulder  210  (shown in  FIG. 9 ) is located adjacent the first end  204 . 
   The housing cap  203  of the housing  172   a  includes an enlarged diameter portion  212  that necks down to a reduced diameter portion  214 . As shown in  FIGS. 8 and 9 , the housing piece  203  is hollow and defines an inner, annular retaining recess  216 . The enlarged diameter portion  212  includes one or more axial slots  218  for allowing the enlarged diameter portion  212  to elastically flex radially outwardly to snap fit over the second end  206  of the main housing piece  202 . 
   As shown in  FIGS. 8 and 9 , the conductive pin  170   a  of the tracer lamp assembly  134   a  includes a first end  220  (i.e., a tip end) positioned opposite from a second end  224  (i.e., a base end). The conductive pin  170   a  also includes a resilient tab  226  spaced from a retaining shoulder  228 . A crimping structure  230  is located at the second end  224  of the conductive pin  170   a.    
   Referring to  FIG. 8 , the circuit board assembly  250  of the tracer lamp assembly  134   a  includes an elongate circuit board  252 . The rectifier circuit  180   a , the LED  174   a  and the resistor  178   a  are mounted on the circuit board  252 . The circuit board  252  preferably includes tracings for electrically connecting the rectifier circuit  184   a , the LED  174   a  and the resistor  178   a  in a manner consistent with the schematic shown in FIG.  5 . The circuit board assembly  250  also includes conductive pins  254  and  256  that project outwardly from opposite ends of the elongate circuit board  252 . It will be appreciated that tracings electrically connect the conductive pins  254  and  256  to the components on the circuit board  252 . 
   Referring still to  FIG. 8 , the double-crimp conductor  270  of the tracer lamp assembly  134   a  includes a first crimping structure  272  positioned at an opposite end from a second crimping structure  274 . An enlarged alignment structure  276  is positioned between the crimping structures  272 ,  274 . 
   The tracer lamp assembly  134   a  is assembled by initially performing a sequence of crimping steps. For example, the first conductive pin  254  of the circuit board assembly  250  can be crimped within the crimping structure  230  of the pin  170   a . Also, the second conductive pin  256  of the circuit board assembly  250  can be crimped within the crimping structure  272  of the double crimp conductor  270 . Further, a stripped end of the messenger wire  130  can be inserted through the cap  203  of the housing  172   a  and crimped within the crimping structure  274  of the double crimped conductor  270 . 
   After the components have been crimped together as described above, the entire crimped assembly is inserted through the second end  206  of the main housing piece  202 . The assembly is pushed toward the first end  204  of the main housing piece  202  until the resilient tab  226  of the pin  170   a  snaps past the inner shoulder  210  of the housing piece  202  as shown in FIG.  9 . With the resilient tab  226  snapped in place, the shoulder  210  is trapped between the resilient tab  226  and the retaining shoulder  228  of the conductive pin  170   a . This limits axial movement of the conductive pin  170   a  relative to the housing  172   a.    
   With the conductive pin  170   a  snapped in place as shown in  FIG. 9 , the first end  220  of the conductive pin  170   a  projects axially outwardly from the first end  204  of the main housing piece  202 , and the circuit board assembly  250  is enclosed within an internal cavity of the main housing piece  202 . Further, the alignment structure  276  of the double-crimp conductor  270  fits within the second end  206  of the main housing piece  202  to assist in aligning the crimping structures  272 ,  274  with a center axis of the housing  272   a . The pin  127   a  also co-axially aligns with the housing  172   a.    
   Once the conductive pin  170   a  has been snapped within the housing  172   a , the cap  203  of the housing  172   a  is pushed over the second end  206  of the main housing piece  202 . Preferably, the cap  203  is pushed onto the housing piece  202  until the retaining shoulder  208  of the main housing piece  202  snaps within the retaining recess  216  of the cap  203 . Once this occurs, the pieces  202 ,  203  are interconnected by a snap-fit connection. However, it will be appreciated that other types of connections such as a press fit connection, a fastener type connection or an adhesive connection could also be used.  FIG. 9  shows the shoulder  208  snapped within the retaining recess  216 . 
     FIG. 10  shows an alternate tracer lamp assembly  300  that is an embodiment of certain inventive aspects in accordance with the principles of the present disclosure. The assembly  300  includes a translucent housing  302  having a hollow, cylindrical configuration. Tracer lamp circuitry is mounted within the housing. The tracer lamp circuitry includes a conductive pin  304 , a circuit board  306 , and a crimping structure  308 . The conductive pin  304  and the conductive crimping structure  308  are connected to the circuit board  306  by a surface mount connection technique. An LED  310  and a resistor  312  are also surface mounted on the circuit board  306  by a surface mount connection technique. The conductive pin  304  includes a threaded portion  314  having external threads that thread within corresponding internal threads (not shown) within the housing  302  to hold the tracer lamp circuitry within the housing. To mount the tracer lamp circuitry within the housing, the tracer lamp circuitry is inserted through a first end  303  of the housing  302  and threaded into a locked position where the conductive pin  304  projects from the first end  303  of the housing  302  and the crimping structure  308  aligns with a clearance hole  307  defined at a second end  309  of the housing  302 . In certain embodiments, the assembly  300  also includes a rectifier circuit. However, other configurations for routing current through the LED  310  in the proper illumination direction can also be used. 
     FIG. 11  illustrates another tracer lamp assembly  400  that is an embodiment of certain inventive aspects in accordance with the principles of the present disclosure. The assembly  400  has the same configuration as the assembly of  FIG. 10  except a resistor  412  and an LED  410  are mounted to a circuit board by a through-hole connection technique (e.g., by soldering wires within plated through-holes of the circuit board) as compared to a surface mount connection technique (e.g., by mounting the components to conductive pads on the circuit board). The depicted embodiments of  FIGS. 10 and 12  are used with unidirectional current through the messenger wire. Other embodiments can be bi-directional through the use of rectifier circuits as previously described or diodes arranged in parallel as described in the embodiment of FIG.  13 . 
     FIG. 12  illustrates still another tracer lamp assembly  134 ′ that is an embodiment of certain inventive aspects in accordance with the principles of the present disclosure. The assembly  134 ′ has the same configuration as the assembly  134   a  of  FIG. 8  except that modifications have been made to shorten the assembly to facilitate cable management. For example, a first crimping structure  272 ′ of a double-crimp conductor  270 ′ has been shortened as compared to the first crimping structure  272  of the double crimp conductor  270 . Also, conductive pin  170 ′ does not include a crimping structure. Instead, a second end  224 ′ (i.e., a base end) of the pin  170 ′ is soldered to the conductive pin  254  of the circuit board assembly  250 . Further, a housing  172 ′ of the assembly  134 ′ has been shortened as compared to the housing  172  of the assembly  134   a.    
     FIG. 13  is a schematic diagram of another jumper assembly  500  that is an example of how certain inventive aspects disclosed herein may be practiced. The jumper assembly  500  includes two jumper cables  502 ,  504  and a messenger wire  506 . Light emitting diode structures  508  are carried with the messenger wire  506 . Each light emitting diode structure  508  includes a housing  510  containing two light emitting diodes  512 ,  514 . The light emitting diodes  512 ,  514  are aligned in parallel and have opposite current pass directions. This configuration ensures that the light emitting diode structures  508  will illuminate regardless of the direction of current flow through the messenger wire  506 . For example, the diodes  514  will illuminate when current flows from right to left through the messenger wire  506 , and the diodes  512  will illuminate when current flows from left to right through the messenger wire  506 . 
     FIG. 14  schematically shows an alternative jumper assembly  624  with an integral tracer lamp that is an embodiment of certain inventive aspects in accordance with the principles of the present disclosure. The jumper assembly  624  includes jumper cables  626  and  628  and a messenger wire  630  that is preferably secured to the jumper cables  626 ,  628 . Tracer lamps  634   a ,  634   b  are carried with the messenger wire  630 . The tracer lamps  634   a ,  634   b  are shown including translucent housings  672   a ,  672   b  containing LED&#39;s  674   a ,  674   b , rectifier circuits  680   a ,  680   b  and resistors  671   a ,  671   b . However, it will be appreciated that other types of lighting elements adapted to be illuminated by current traveling through the messenger wire  630  could also be used. 
   Referring still to  FIG. 14 , conductive pins  670   a ,  670   b  are mounted at opposite ends of the messenger wire  630 . The pins  670   a ,  670   b  are adapted to be received within sockets of conventional pin jacks. The tracer light structures  634   a ,  634   b  are offset from the conductive pins  670   a ,  670   b . For example, a spacing S separates each of the tracer lamp structures  634   a ,  634   b  from its respective conductive pin  670   a ,  670   b . In one embodiment, the spacing is from 2-9 inches. In a more preferred embodiment, the spacing is from 3-6 inches. 
   The tracer lamp structures  634   a ,  634   b  are shown positioned in line with the messenger wire  630 . For example, as shown in  FIG. 14 , the messenger wire  630  includes a first portion  650  that extends between the tracer lamp structures  634   a ,  634   b , a second portion  652  that traverses the spacing between the conductive pin  670   a  and the tracer lamp structure  634   a , and a third portion  654  that traverses the spacing between the conductive pin  670   b , and the tracer lamp structure  634   b . The spacings provided by the portions  652 ,  654  of the messenger wire  630  assist in promoting cable management and also assist in allowing the tracer lamp structures  634   a ,  634   b  to be positioned at a location of increased visibility (e.g., offset a predetermined distance from a corresponding rack). 
     FIGS. 15 and 16  illustrate an exemplary configuration for the tracer lamp structure  634   a . It will be appreciated that the tracer lamp structure  634   b  can have the same configuration. 
   Referring to  FIGS. 15 and 16 , the translucent housing  672   a  of the tracer lamp structure  634   a  includes a middle portion  602  and two snap fit end caps  603 . The end caps  603  are adapted to snap on the middle piece  602  in the same manner that the cap  203  of the housing  172   a  of  FIG. 8  snaps onto the main housing piece  202 . 
   Referring still to  FIGS. 15 and 16 , the tracer lamp structure  634   a  also includes a circuit board assembly  690  including a circuit board  691  on which the rectifier circuit  680   a , the diode  674   a  and the resistor  671   a  are mounted. Tracings (not shown) can connect the circuit components in a manner consistent with the schematic of FIG.  14 . Conductive pins  694  and  695  project outwardly from the circuit board  691 . The conductive pins  694 ,  695  provide connection locations for coupling the components of the circuit board assembly  690  to double crimps  696 ,  697 .  FIG. 16  shows the crimps  696 ,  697  crimped upon the conductive pins  694 ,  695 . 
   When fully assembled, the circuit board assembly  690  mounts within the housing  672   a . The double crimps  696 ,  697  include centering members  699  for centering the circuit board assembly  690  within the housing  672   a . The crimps  696 ,  697  provide means for coupling the first and second portions  650 ,  652  of the messenger wire  630  to the circuit board assembly  690 . The end caps  603  have been omitted from  FIG. 16  for clarity. 
   While example embodiments have been shown and described herein, it will be appreciated that many different embodiments of the inventions can be made without departing from the spirit and scope of the inventions. For example, each of the depicted embodiments shows tracer lamps positioned directly in-line with their corresponding messenger wires. In other embodiments, the tracer lamps can be indirectly coupled to their corresponding messenger wires by techniques such as an inductive coupling.