Abstract:
The subject disclosure relates improved common mode choke (CMC) and integrated connector module (ICM) designs for Ethernet applications. Some aspects provide an improved CMC component, including an upper chassis element having a first plurality of comb structures vertically protruding from an edge of the upper chassis element, and a lower chassis element comprising a second plurality of comb structures vertically protruding from an edge of the lower chassis element, the second plurality of comb structures configured to interlock with the first plurality of comb structures to form an enclosure when the upper chassis element is mechanically coupled with the lower chassis element.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The subject technology relates to improved common mode choke (CMC) and integrated connector module (ICM) designs, and in particular, provides design improvements to optimize CMC and ICM process automation. 
         [0003]    2. Introduction 
         [0004]    Suppression of electromagnetic interference (EMI) has become a major concern in the transmission, reception, and processing of electronic signals and data. Modern communication systems are often designed as an interconnection of functional blocks and connections made using cables or wiring harnesses. Such interconnections often present opportunity for common mode current loops between devices that can lead to EMI regulatory failure. 
         [0005]    Due to EMI concerns, Ethernet devices, such as Ethernet ICM transformers (ICMts), are often coupled with a common mode choke (CMC). A CMC can comprise two coils wound on a single core and may be useful for EMI and Radio Frequency interference (RFI) prevention from, for example, power supply lines and other sources. A CMC can pass differential currents (e.g. equal but opposite), while blocking common-mode currents. Thus, when properly operated, CMCs filter common mode currents without causing signal degradation. Therefore, the addition of CMCs, e.g., in conjunction with a connector such as an ICM, can provide filtration of mode currents, while also allowing passage of desired signals. 
         [0006]    In some traditional configurations, CMCs and ICMs are bundled together, for example into a common ICM housing. By way of example, CMC and ICM components can be bundled into “pigtail” components, which provide connections between the CMC and ICM as well as a shared housing. Bundling of the ICM and CMC into the pigtail is a labor intensive process and makes it nearly impossible to later separate the ICM/CMC from the pigtail to make component modifications or adjustments. 
         [0007]    For example, the ICM can include an Ethernet transformer that is configured (tuned) to block ground currents, e.g., of a corresponding Ethernet transceiver or “PHYreceiver.” In contrast, the CMC is generally tuned to filter noise produced by other device components in which the ICM is disposed. Because noise resulting from the other components can vary with the life of the device, or as device changes are made, it is not uncommon to require re-tuning of the CMC. To simplify the ability to tune/re-tune the choke, some Ethernet implementations provide physically decoupled CMC and ICM modules (as opposed to pigtails in which the respective components cannot be easily decoupled). 
         [0008]    In such configurations, separate CMC and ICM components are physically separated but electrically coupled, for example, via a printed circuit board (PCB). The physical decoupling of CMC and ICM components can provide the groundwork for several advantageous modifications to conventional CMC and ICM architecture. 
       SUMMARY 
       [0009]    Aspects of the subject technology provide a common mode choke (CMC) component including a housing, the housing including an upper chassis element and a lower chassis element, the upper chassis element comprising a first plurality of comb structures vertically disposed around an edge of the upper chassis element. In certain aspects, the lower chassis element includes a second plurality of comb structures vertically disposed around an edge of the lower chassis element, the second plurality of comb structures configured to interlock with the first plurality of comb structures to form an enclosure when the upper chassis element is mechanically coupled with the lower chassis element. Additionally, in some implementations, a mechanical coupling between the upper chassis element and the lower chasses element forms a wire gap between an inside of the enclosure and an outside of the enclosure. 
         [0010]    In yet another aspect, the subject technology relates to an integrated connector module transformer (ICMt), including a wafer configured to hold a plurality of toroid elements, and wherein the wafer is comprised of a two or more mechanically coupled wafer portions. In certain implementations, the ICMt can further include a plurality of tie-off pins configured to protrude from at least one of the two or more wafer portions, and wherein the tie-off pins are disposed at an angle between two and eighty-eight degrees with respect to the at least one of the two or more wafer portions. 
         [0011]    It is understood that other configurations of the subject technology will become readily apparent to those skilled in the art from the following detailed description, wherein various configurations of the subject technology are shown and described by way of illustration. The subject technology is capable of other and different configurations and its several details are capable of modification in various respects without departing from the scope of the subject technology. Accordingly, the detailed description and drawings are to be regarded as illustrative and not restrictive in nature. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Certain features of the subject technology are set forth in the appended claims. However, the accompanying drawings, which are included to provide further understanding, illustrate disclosed aspects and together with the description serve to explain the principles of the subject technology. In the drawings: 
           [0013]      FIG. 1  illustrates an example of a common mode choke (CMC) and integrated connector module transformer (ICMt), according to certain aspects of the subject technology. 
           [0014]      FIG. 2A  illustrates an exploded view of an example of a CMC housing, according to certain aspects. 
           [0015]      FIG. 2B  illustrates an example of a lower chassis element of a CMC housing, including multiple toroid elements, according to certain aspects of the technology. 
           [0016]      FIG. 2C  conceptually illustrates an example of the coupling between an upper chassis element and lower chassis element for form a CMC housing, according to certain aspects of the technology. 
           [0017]      FIG. 2D  conceptually illustrates a cut-away view of an assembled CMC housing, including magnetic elements, according to some aspects of the technology. 
           [0018]      FIG. 2E  illustrates a side perspective view of a CMC housing, including a plurality of pegs, each including a respective toroid-wire tie off, according to some aspects of the technology. 
           [0019]      FIG. 2F  illustrates a side illustrates a side perspective view of a CMC housing, including a plurality of pegs (without toroid wires), according to some aspects of the technology. 
           [0020]      FIG. 2G  illustrates a perspective view of a peg, including a wire cutting mechanism, according to some aspects of the technology. 
           [0021]      FIG. 2H  provides a cut away view of pegs illustrated by  FIG. 2F , according to some aspects of the technology. 
           [0022]      FIG. 3A  illustrates an example of a perspective view of an integrated connector module (ICM) component, according to some aspects of the subject technology. 
           [0023]      FIG. 3B  conceptually illustrates an exploded view of an example ICM chassis having multiple wafer portions, according to some aspects of the technology. 
           [0024]      FIGS. 3C ,  3 D, and,  3 E illustrate a cut-away view of an ICM, including toroid tie-off pins, according to some aspects of the technology. 
           [0025]      FIG. 4A  illustrates an example of a dual-layer printed circuit board (PCB) according to some aspects of the technology. 
           [0026]      FIG. 4B  illustrates an example of a single-layer PCB, according to some aspects of the technology. 
           [0027]      FIG. 5  illustrates an example of Ethernet channel routing on a PCB, according to some aspects of the technology. 
           [0028]      FIG. 6  illustrates an ICM grounding configuration which utilizes case contact pins and PCB contact pins, according to certain aspects of the technology. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The detailed description set forth below is intended as a description of various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology can be practiced. The appended drawings are incorporated herein and constitute a part of the detailed description. The detailed description includes specific details for the purpose of providing a more thorough understanding of the subject technology. However, it will be clear and apparent that the subject technology is not limited to the specific details set forth herein and may be practiced without these details. In some instances, structures and components are shown in block diagram form in order to avoid obscuring the concepts of the subject technology. 
         [0030]      FIG. 1A  illustrates an example of a CMC/ICM configuration in which CMC  110  and ICM  120  are provided as separate component parts. Specifically,  FIG. 1  depicts CMC  110  and ICM  120  as physically separated, but electrically coupled via printed circuit board (PCB)  130 . 
         [0031]    As shown in  FIG. 1A , ICM  120  also includes EMI fingers  121 A and  121 B that are positioned to provide contact between ICM  120  and a surrounding enclosure or EMI shield (not shown). By providing an electrical contact to a surrounding enclosure, EMI fingers  121 A and  121 B provide a ground signal path from ICM  120  into an external ground, decreasing the likelihood that EMI will affect ICM or system performance. To this end, ICM  120  also includes ground pin  122  and EMI finger  123 , which both provide an electrical connection to the circuit ground of PCB  130 . The relatively forward position of EMI finger  123  can help to dissipate stray electrical signals before they reach other components (or ground pin  122 ). The addition of EMI fingers (such as EMI finger  123 ) to ICM  120  helps reduce the need for electrical shielding (e.g., faraday shielding) that is conventionally used to enclose side, top and back portions of ICM  120 . 
         [0032]    As discussed in further detail below, the physical separation of CMC  110  and ICM  120  is instrumental in realizing design advantages for each respective component. 
       Common Mode Choke Geometry: 
       [0033]    One problem in conventional CMC designs relates to the way in which toroid wire management is performed throughout assembly. In conventional deigns, toroid wires are jumbled together and left to protrude from a single opening of the CMC enclosure, and must then be manually sorted and separated before being tied off. This wire management process is both cumbersome and time consuming, adding to the difficulty and cost of CMC manufacture. As such, there is a need for an improved CMC housing geometry, which facilitates toroid wire management. 
         [0034]    Another problem in conventional CMC designs relates to the way in which toroid wires (of a magnetic toroid element) are tied off, for example, onto pegs external to the CMC housing. In conventional CMC designs, the pegs are of a circular or square shape and distend from the outer housing surface. These pegs are configured to receive the ends of the toroid wires, which are wrapped around the pegs and broken off during the assembly process. However, the force produced from stretching (and breaking) the wire often causes the supporting (symmetrical) peg to shear off from the housing. Accordingly, an improved peg geometry is needed to enhance overall durability of the CMC housing and to provide pegs that are strong enough to resist greater shear forces. 
         [0035]    Aspects of the technology address both of the foregoing problems by providing a CMC enclosure that facilitates toroid wire management, as well as an improved peg geometry that provides strengthened bonds between the pegs and supporting CMC chassis. 
         [0036]      FIG. 2A  illustrates an example of an exploded view of a CMC housing, including an upper chassis element  212  and a lower chassis element  202 . Upper chassis element  212  includes comb structures  214  as well as a clip  218 . In certain aspects, the geometry of comb structures  214  is configured to integrate with an opposing geometry of lower chassis element  202 . Similarly, the geometry of clip  218  is configured to mechanically couple upper chassis element  212  with lower chassis element  202 . 
         [0037]    Lower chassis element  202  includes comb structures  204  that are configured to alternating integrate with comb structures  214  of upper chassis element  212 . Lower chassis element also includes a clip insert  219  which is configured to mate with clip  218  to the hold upper chassis element  212  and lower chassis element  202  together. More specifically, the interlocking of comb structures  204  with comb structures  214  operates to provide a wire-gap, as discussed in further detail below. As further illustrated, lower chassis element also includes pegs  206 , each of which correspond with respective solder pads  220 . In the illustration of  FIG. 2A , magnetic toroids (or toroid elements)  207  are shown as disposed within lower chassis element  202 ; however, it is understood that a greater number (or lesser number) of toroid elements can be disposed within the CMC, depending on the desired implementation. 
         [0038]    In operation, wires from toroid elements  207  pass from the toroid (on the interior of the CMC enclosure), through an adjacent wire-gap provided by the coupling of comb structures ( 204 , 214 ), and out of the CMC enclosure. Wires protruding out from the CMC housing through the wire-gap are then tied off on an adjacent peg (e.g., one of pegs  206 ). As discussed below, assembly of the CMC involves ablating the wire wrapped on pegs  206  using an incident laser, to remove any lacquer or insulation. Subsequently, a solder joint is formed between the wrapped wire and a corresponding solder pad (e.g., solder pad  220 ). 
         [0039]      FIG. 2B  illustrates an example of a lower chassis element  202 , together with toroids  207 , which are separated by separator  224 . In the view of  FIG. 2B , an exemplary peg geometry is depicted by pegs  206 , which are shown without a wire wrap. Although pegs  206  can be differently shaped depending on implementation, in certain aspects, the geometry of pegs  206  is asymmetrical, yet substantially round in shape. Asymmetrical peg geometries (such as that shown in  FIG. 2B ), can help improve peg resistance to shear forces experienced by the pegs in during toroid wire tie-off. In addition to providing a stronger peg foundation, asymmetrical peg geometries also provide an improved surface on which toroid wire can be wound and ablated to remove insulation. 
         [0040]    By way of example, a preferred peg geometry can include a shape that is larger in the middle (or center) to improve peg strength. Additionally, in some implementations, a top surface of the peg is larger (e.g., of a greater surface area) compared to that of the bottom surface. An increased surface area on the top side of the peg can increase exposure of the corresponding wire wrap to laser light incident on the top surface (e.g., for removal of lacquer or insulation) during the CMC manufacture process. In contrast, a more narrow shape (e.g., smaller surface area) on the bottom side of the peg helps to provide an angular shape that is more conducive to the formation of strong solder joints, e.g., as between the wrapped toroid wire and the corresponding solder pad, e.g., solder pad  220  illustrated in  FIG. 2A . 
         [0041]    Lower chassis element further includes separator  224  which provides a non-conductive barrier between toroids  207 . The configuration of separator  224  and comb structures  204  mechanically restrains toroids  207 , without the use of epoxy or silicone bonding agents, which affect the electrical and/or magnetic properties of toroids  207 . By eliminating the need for conductive toroid restraints, the dielectric of toroids  207  remains equal to that of the air filling the gaps in the CMC housing. As such, the mechanical restraint features of CMC  110  serve to enhance the electrical properties of conditions in and around the CMC housing. 
         [0042]    Additional features of the CMC housing, including additional restraint mechanisms, are provided when upper chassis element  212  is coupled with lower chassis element  202 .  FIG. 2C  illustrates an example of the coupling between an upper chassis element and lower chassis element for forming a CMC housing. 
         [0043]    Specifically, in  FIG. 2C , upper chassis element  212  is shown to be fixed to lower chassis element  202 , causing combs  214  and  204  to alternating integrate to form wire gap  217 , which can be used to separate/manage toroid wires that are to be wrapped around pegs  206 . That is, the interlocking of combs  214  and  204  causes the toroid wires to become trapped, and prevents the straying or shifting of wires during assembly. 
         [0044]    In certain aspects, cooperation between upper chassis element  212  and lower chassis element  202 , (e.g., to form the CMC housing) is accomplished using a mechanical locking mechanism. By way of example, clip  218  of upper chassis element  212  is configured to connect with lower chassis element  202  using clip insert  219 . 
         [0045]    In certain aspects, upper chassis element  212  also includes restraint features for imparting a force on toroids  207 , to provide further mechanical support. For example, upper chassis element  212  includes spring fingers  216  that are disposed on the inner surface of upper chassis element  212 . When upper chassis element  212  is lowered on onto lower chassis element  202 , spring fingers  216  contact with, and mechanically secure toroids  207 . 
         [0046]    A further illustration of the contact between spring fingers  216  and toroids  207  is provided by  FIG. 2D , which conceptually illustrates a cut-away view of an assembled CMC housing, including magnetic elements, according to some aspects of the technology.  FIG. 2D  further illustrates how clip  218  can be used for coupling upper chassis element  212  with lower chassis element  202 , as well as the separation of toroids  207  using separator  224 . As discussed above, the mechanical restraint provided by spring fingers  216  and separator  224  eliminates the need to use filling or bonding agents, such as epoxy or silicon, which can alter the electrical properties of toroids  207  and/or introduce moisture into the CMC housing. 
         [0047]      FIG. 2E , provides a perspective view of a manner in which combs  214  (e.g., of upper chassis element  212 ) can mechanically integrate with combs  204  of lower chassis element  202 . As illustrated, the cooperation of combs  214  and combs  212  form wire gaps  217 , which allow space for toroid wires  207 . As shown, toroid wires  207  are pulled from the interior of the CMC housing (and through wire gaps  217 ) are wrapped around corresponding pegs  206 . Thus, wire gaps  217  provide a space through which toroid wires  207  may be separated/sorted before being wound and terminated on pegs  206 . 
         [0048]    As further shown in  FIG. 2E , each of pegs  206  is paired with a respective solder pad  220 , that provides a surface against which a solder joint (e.g., a SMT solder joint) may be formed. A distance  221  separating solder pads is also shown, which can be determined based on a minimum clearance needed to sufficiently reduce cross talk interference between adjacent pads. 
         [0049]      FIG. 2F  illustrates a view similar to that of  FIG. 2E , but with the toroid wires  207  removed to further reveal the geometry of pegs  206 . In certain aspects, an outermost portion of the pegs is larger in circumference than the supporting shaft portion fixed to the outer surface of lower chassis element  202 . In certain implementations, this geometry helps to prevent the toroid wire from slipping from the supporting peg. A more detailed perspective of a peg is illustrated in  FIG. 2G . 
         [0050]    Specifically,  FIG. 2G  illustrates a side perspective view of a peg (e.g., peg  206 ), including a wire cutting mechanism  222 , according to some aspects of the technology. As illustrated, wire cutting mechanism  222  is placed on a top corner edge of the shaft supporting peg  206 . However, it is understood that wire cutting mechanism  222  may be disposed in other (or multiple) locations around peg  206 , depending on implementation. By way of example, a cutting mechanism may be provided on an inner surface of the larger portion of peg  206 , as discussed above. 
         [0051]    In operation, wire cutting mechanism  222  facilitates the severance of wires as they are pulled from peg  206  during the CMC assembly process. For example, after the completion of toroid wire wrapping, the wire is pulled against cutting mechanism  222 , causing the wire to sever and break off. By providing cutting mechanism  222 , smaller forces can be exerted to break/cut the wrapped toroid wire, reducing the likelihood that the peg will shear or twist off from the supporting chassis element. 
         [0052]    In some implementations, after toroid wrapping is complete, the wrapped toroid wire is subjected to laser stripping e.g., by laser light incident on the top of the peg surface. Laser stripping removes insulation from the wrapped toroid wire. In certain aspects, peg geometries, such as that of pegs  206 , facilitates the laser stripping process, for example, by providing a flatter and larger surface area on the top side of the peg which can be reached with laser light. Additionally, the substantially flat top outer surface of the peg can help to reduce reflection of incident light, increasing the efficacy of laser ablation on the top surface. Thus, the geometry of pegs  206  not only improves mechanical integrity, but also facilitates the preparation and soldering of toroid wire. Further advantages of the subject peg geometry are illustrated by the view provided in  FIG. 2H . 
         [0053]    Specifically,  FIG. 2H  provides a cut-away view of the pegs  206  illustrated in  FIG. 2F , discussed above. In the example of  FIG. 2H , wire cutting mechanisms  222  are shown on both sides of the top peg surface. However, as discussed above, wire cutting mechanisms can be disposed at additional or different locations around the peg surface. 
         [0054]      FIG. 2H  also illustrates an example of a solder joint  230  that is provided between solder pad  220  and the toroid wire of peg  206 . In certain implementations, the geometry of peg  206  provides angular edges along the lower surface, which facilitates the formation of a triangular shaped solder joint, such as solder joint  230 . Such angles provide an increased surface area of contact as between the wrapped toroid wire and solder joint  230 , as well as solder joint  230  and solder pad  220 . 
         [0055]      FIG. 3A  illustrates an example of a perspective view of an integrated connector module (ICM) component  300 . In certain aspects, a chassis of the ICM can be comprised of two more wafer portions. For example, in the illustration of  FIG. 3A , ICM  300  includes first wafer  301 A, second wafer  301 B, third wafer  301 C, and fourth wafer  301 D. Additionally, ICM  300  includes toroids  302 , as well as toroid wire tie-off pins (“pins”), shown in a first position ( 304 A), as well as a second position ( 301 B). It is understood that an ICM of the subject technology can include a greater (or fewer) number of wafer portions from that illustrated in  FIG. 3A . Similarly, a greater or lesser number of toroids and/or pins can be used, without departing from the scope of the invention. 
         [0056]    A more detailed view of the ICM wafer assembly is shown in  FIG. 3B , which illustrates an exploded perspective view of ICM  300 . In some implementations, the various wafer portions of ICM  300  (e.g. first wafer  301 A, second wafer  301 B, third wafer  301 C and fourth wafer  301 D), can be held together using physical clips or hooks (as illustrated) to provide a mechanical coupling between the different wafer portions, forming the chassis of ICM  300 . However, it is understood that other mechanical means can be used to form a coupling between multiple wafer portions of the ICM chassis. 
         [0057]    By using a mechanical mechanism to couple the multiple wafer portions, an ICM of the subject technology eliminates the need for adhesives such as epoxy or silicon, which can alter the electrical properties of toroids  302  and slow the ICM production process. As such, waferization of the ICM chassis provides several advantages, including improving the dielectric properties of toroids  302  (e.g., by eliminating conductive bonding media) and streamlining the ICM production process. 
         [0058]    Aspects of the subject technology also provide an improved process and ICM geometry for relieving mechanical strain placed on toroid wires that are tied off on pins  304 . Specifically, in some implementations, as illustrated in  FIG. 3A , toroid wires are tied off onto pins  304 A (in a first position), wherein pins  304 A are substantially perpendicular to the ICM chassis body. After the toroid wires have been tied off, the pins are bent into a second position ( 304 B), creating slack in the toroid wire connection between the toroid and the corresponding pin. 
         [0059]      FIGS. 3C-3D  illustrate ICM configurations throughout a process for creating slack in tied-off toroid wires, according to some implementations. Specifically,  FIG. 3C  illustrates two separate wafer assemblies, each including toroids  302 . Wires wrapped around toroids  302  are tied off onto pins  304 A, creating tension on the respective wires. To relieve the tension, the pins are shifted into an angled position (e.g.,  304 B), as shown in  FIG. 3D . In the illustrated example, angle  303  indicates an amount of angular movement experience from pin position  304 A to  304 B. 
         [0060]    Once pins  304 B are in their final (angled) positions, the separate wafer assemblies are combined. It is understood that the angle of pins  304 B with respect to the supporting chassis (or wafer) can vary with implementation. For example, pins  304 B can come to rest at an angle that is greater than zero, but less than ninety degrees, with respect to the supporting chassis body. 
         [0061]      FIG. 3E  illustrates final positions of pins  304 B, as well as the separate wafer portions. In certain aspects, wafer bonding first requires the bending of pins  304 A, so that the pins do not interfere with the mechanical coupling of separate wafer portions. 
         [0062]    As discussed above with respect to  FIG. 1 , separation of CMC  110  and ICM  120  components can provide the basis of design improvements to both component parts. Likewise, physical separation of CMC  110  and ICM  120  can facilitate improvements to PCB design, such as that of PCB  130 . 
         [0063]    Turning to  FIG. 4A  which conceptually illustrates an example of a PCB  400  that is implemented using two-layer routing. As illustrated,  FIG. 4A  depicts two sets of routing paths, e.g., first routing path  402  and second routing path  404 , 
         [0064]    In certain aspects, first routing path  402  and second routing path  404  are provided on different layers of PCB  130 . By way of example, first routing path  402  can be configured to cross over second routing path  404  using an orthogonal (i.e., 90 degrees) crossover e.g., to reduce cross-talk interference. By implementing two-layer routing in PCB  400 , the subject technology can serve to reduce manufacturing costs, without realizing unacceptable levels of EMI or cross talk interference in PCB  400 . 
         [0065]    In another implementation, a PCB of the subject technology can be implemented using single layer routing. For example,  FIG. 4B  illustrates an example of a PCB  401 , that includes route  403  and route  405  that are provided on a common layer. In certain aspects, route  405  can be configured to cross route  403  using a capacitive element (not shown) that is connected across pads  410 A and  410 B. That is, route  405  is provided through a capacitive element (e.g., a capacitor) via pads  410 A and  410 B. 
         [0066]    In some implementations, a PCB board of the subject technology provides a unique channel routing e.g., for Ethernet channel routing.  FIG. 5  illustrates an example of a PCB  500 , which includes a first Ethernet channel  502 , which is separated into three channel slices, e.g., first channel slice  504 A, second channel slice  504 B and third channel slice  504 C. 
         [0067]    Although the number of channels carried by the channel slices, as well as the width of each individual channel slice can vary with implementation, in certain aspects first channel slice  504 A, second channel slice  504 B and third channel slice  504 C will carry a combined total of eight differential Ethernet pairs at an approximately 75 ohm impedance. 
         [0068]    In another aspect, a PCB of the subject technology (e.g., PCB  130 ), provides straight runs from a front of the board to the back of the board. For example, with reference to  FIG. 1 , printing of PCB  130  can provide substantially straight routing from ICM  120  through CMC  110 . 
         [0069]      FIG. 6  provides an example of a bottom perspective view of an ICM assembly  600 , which includes a PCB  601  and an ICM wrapper  605 . As illustrated, a set of first contact fingers (e.g., contact fingers  601 A-E) extend from ICM wrapper  605 . Additionally, a second set of contact fingers (e.g., contact fingers  603 A- 603 F) is shown underneath PCB  601 . 
         [0070]    In operation, first contact fingers  601 A-E are configured to make electrical contact between an external chassis or case (not shown), when the case is fitted over ICM assembly  600 . Accordingly, first contact fingers  601 A-E an electrical coupling from ICM wrapper  605  and a case ground. The electrical connection between contact fingers  601 A-E and the case provides a path by which stray EMI currents can be safely dissipated, without affecting other device components. 
         [0071]    Similarly, the second set of contact fingers (e.g.,  603 A- 603 F) provide a ground connection between an ICM (not shown), and PCB  601 . In certain aspects, the additional ground path provided by contact fingers  603 A-F provides a low-impedance ground path from the ICM into the PCB, and eliminates the need for portions of the ICM wrapper, which would otherwise provide a similar function. That is, the addition of contact fingers  603 A-F increases the availability of an electrical ground connection between the PCB and the supported ICMs. 
         [0072]    By eliminating portions of the ICM wrapper, the subject technology provides ICM grounding configurations that reduce manufacturing costs while maintaining safety compliance. 
         [0073]    In yet another aspect, the CMC and ICM configurations of the subject technology provide PCB layout configurations that facilitate the placement of lights, such as LEDs, at symmetrical positions around the ICM. By way of example, an ICM of the subject technology may be flanked by LEDs, which are used to signal to an external operator or user, that a corresponding connection if the illuminated ICM is active. In some implementations, a light-pipe or tube can be used to transmit light from the surface of the PCB (where the LEDs are mounted), and an external surface of the case or enclosure, so that they are visible to the user. 
         [0074]    The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” 
         [0075]    A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A phrase such as a configuration may refer to one or more configurations and vice versa. 
         [0076]    The word “exemplary” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs.