Patent Publication Number: US-11656418-B2

Title: Power and optical fiber interface

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. Non-Provisional patent application Ser. No. 16/704,964, filed Dec. 5, 2019, now U.S. Pat. No. 11,215,776, issued Jan. 4, 2022, which is a continuation application of U.S. Non-Provisional patent application Ser. No. 15/985,068, filed May 21, 2018, now U.S. Pat. No. 10,502,912, issued Dec. 10, 2019, which is a continuation of U.S. Non-Provisional patent application Ser. No. 15/373,709, filed Dec. 9, 2016, now U.S. Pat. No. 9,977,208, issued May 22, 2018, which is a continuation application of U.S. Non-Provisional patent application Ser. No. 14/331,873, filed Jul. 15, 2014, now U.S. Pat. No. 9,557,505, issued Jan. 31, 2017, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/846,392, filed Jul. 15, 2013 and is a continuation-in-part of PCT Patent Application No. PCT/US2014/030969, filed Mar. 18, 2014, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/802,989, filed Mar. 18, 2013. The disclosures of all of the above-mentioned patent applications are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     The present disclosure relates generally to hybrid optical fiber and electrical communication systems. 
     Rapid growth of portable high-speed wireless transceiver devices (e.g., smart phones, tablets, laptop computers, etc.) continues in today&#39;s market, thereby creating higher demand for untethered contact. Thus, there is growing demand for integrated voice, data and video capable of being transmitted wirelessly at data rates of 10 Gbits/second and faster. To provide the bandwidth needed to support this demand will require the cost effective and efficient deployment of additional fixed location transceivers (i.e., cell sites or nodes) for generating both large and small wireless coverage areas. Fiber optic technology is becoming more prevalent as service providers strive to deliver higher bandwidth communication capabilities to customers/subscribers. The phrase “fiber to the x” (FTTX) generically refers to any network architecture that uses optical fiber in place of copper within a local distribution area. Example FTTX networks include fiber-to-the-node (FTTN) networks, fiber-to-the-curb (FTTC) networks, fiber-to-the-home (FTTH), and more generally, fiber-to-the-wireless (FTTW). 
     SUMMARY 
     In accordance with aspects of the present disclosure, examples of a power and optical fiber interface system include a housing having an interior. A cable inlet is configured to receive a hybrid cable having an electrical conductor and an optical fiber. An insulation displacement connector (IDC) is situated in the interior of the housing configured to electrically terminate the conductor, and a cable outlet is configured to receive an output cable that is connectable to the IDC and configured to output signals received via the optical fiber. 
     In accordance with further aspects of the disclosure, examples of the disclosed system include a power converter, such as a DC-DC converter electrically connected to the IDC. An optical fiber management device, such as an optical splice device, is situated in the interior of the housing and configured to receive the optical fiber. A media board is included in some embodiments that is configured to convert optical signals to electrical signals. In some implementations, the IDC includes a housing with a fiber pass-through groove configured to route optical fibers through the housing of the IDC, and first and second conductor grooves are situated on either side of the fiber pass-through groove to receive first and second conductors. 
     Another aspect of the present disclosure relates to a powered fiber optic system. The powered fiber optic system includes a first location including a power source and fiber optic network access and a plurality of active devices remotely positioned with respect to the first location. The powered fiber optic system further includes a plurality of hybrid cables routed from the first location toward the active devices. The hybrid cables include optical fibers for transmitting optical signals and electrical conductors for carrying power. The powered fiber optic system further includes interface devices mounted adjacent to the active devices for providing interfaces between the hybrid cables and the active devices. The interface devices include electrical power management circuitry positioned within the closure for providing DC-to-DC voltage conversion within the closure and also include circuit protection circuitry for providing current surge protection. 
     A further aspect of the present disclosure relates to an interface device for providing an interface between a hybrid cable and an active device. The interface device includes a closure adapted for outside environmental use and a cable anchoring structure for securing a hybrid cable to the closure. The hybrid cable is configured to carry both electrical power and optical signals. The interface device also includes electrical power management circuitry positioned within the closure for providing DC-to-DC voltage conversion within the closure. The electrical power management circuitry is customizable to output one of a plurality of different DC voltage levels such that the DC output level can be matched with a power requirement of the active device. The interface device also includes electrical protection circuitry positioned within the closure and an output configuration for outputting power and communications signals from the interface device to the active device. The output configuration has a format that is customizable and selectable from a plurality of formats that include all of the following formats: a) a power over Ethernet format or a power over Ethernet plus format; and b) a format including one or more optical fibers for the optical signals and separate electrical conductors for power. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a system diagram showing an example distribution of wireless coverage areas deployed using a power and optical fiber interface system in accordance with principles of the present disclosure. 
         FIG.  2    is a transverse cross-sectional view of a power/optical fiber hybrid cable in accordance with principles of the present disclosure. 
         FIG.  3    is a perspective view of a portion of the hybrid cable of  FIG.  2    with electrically conductive portions of the cable showing separated from a central optical fiber portion of the cable. 
         FIG.  4    is a plan view of the hybrid cable of  FIGS.  2  and  3    with the electrically conductive portions of the hybrid cable trimmed relative to the central fiber optic portion of the hybrid cable. 
         FIG.  5    is a transverse cross-sectional view of another power/optical fiber hybrid cable in accordance with principles of the present disclosure. 
         FIG.  6    is a block diagram conceptually illustrating aspects of a communication and power distribution system in accordance with principles of the present disclosure. 
         FIG.  7    is a top view of an interface device in accordance with principles of the present disclosure. 
         FIG.  8    is a perspective view of the interface device shown in  FIG.  7   . 
         FIG.  9    is a partial top view of the interface device shown in  FIG.  7   , illustrating aspects of an insulation displacement connector (IDC) in an open position. 
         FIG.  10    is another partial top view of the interface device shown in  FIG.  7   , illustrating aspects of the IDC in a closed position. 
         FIG.  11    is a perspective view of the interface device shown in  FIG.  7   , illustrating an embodiment that includes an optical splice device. 
         FIG.  12    is a top view of the interface device shown in  FIG.  11   . 
         FIG.  13    is a top view of the interface device shown in  FIG.  7   , illustrating an embodiment that includes a media board. 
         FIG.  14    is a circuit diagram illustrating an example power conditioning circuit. 
         FIG.  15    shows a system in accordance with the principles of the present disclosure having a rack mounted power supply. 
         FIG.  16    shows a hybrid cable system in accordance with the principles of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as top, bottom, front, back, etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense. 
       FIG.  1    shows a system  10  in accordance with the principles of the present disclosure for enhancing the coverage areas provided by cellular technologies (e.g., GSM, CDMA, UMTS, LTE, WiMax, WiFi, etc.). The system  10  includes a base location  11  (i.e., a hub) and a plurality of wireless coverage area defining equipment  12   a ,  12   b ,  12   c ,  12   d ,  12   e  and  12   f  (sometimes collectively referred to as equipment  12  herein) distributed about the base location  11 . In certain examples, the base location  11  can include a structure  14  (e.g., a closet, hut, building, housing, enclosure, cabinet, etc.) protecting telecommunications equipment such as racks, fiber optic adapter panels, passive optical splitters, wavelength division multiplexers, fiber splice locations, optical fiber patching and/or fiber interconnect structures and other active and/or passive equipment. In the depicted example, the base location  11  is connected to a central office  16  or other remote location by a fiber optic cable such as a multi-fiber optical trunk cable  18  that provides high band-width two-way optical communication between the base location  11  and the central office  16  or other remote location. In the depicted example, the base location  11  is connected to the wireless coverage area defining equipment  12   a ,  12   b ,  12   c ,  12   d ,  12   e  and  12   f  by hybrid cables  20 . The hybrid cables  20  are each capable of transmitting both power and communications between the base location  11  and the wireless coverage area defining equipment  12   a ,  12   b ,  12   c ,  12   d ,  12   e  and  12   f.    
     The wireless coverage area defining equipment  12   a ,  12   b ,  12   c ,  12   d ,  12   e  and  12   f  can each include one or more wireless transceivers  22 . The transceivers  22  can include single transceivers  22  or distributed arrays of transceivers  22 . As used herein, a “wireless transceiver” is a device or arrangement of devices capable of transmitting and receiving wireless signals. A wireless transceiver typically includes an antenna for enhancing receiving and transmitting the wireless signals. Wireless coverage areas are defined around each of the wireless coverage area defining equipment  12   a ,  12   b ,  12   c ,  12   d ,  12   e  and  12   f . Wireless coverage areas can also be referred to as cells, cellular coverage areas, wireless coverage zones, or like terms. Examples of and/or alternative terms for wireless transceivers include radio-heads, wireless routers, cell sites, wireless nodes, etc. 
     In the depicted example of  FIG.  1   , the base location  11  is shown as a base transceiver station (BTS) located adjacent to a radio tower  24  supporting and elevating a plurality the wireless coverage area defining equipment  12   a . In one example, the equipment  12   a  can define wireless coverage areas such as a macrocells or microcells (i.e., cells each having a coverage area less than or equal to about 2 kilometers wide). The wireless coverage area defining equipment  12   b  is shown deployed at a suburban environment (e.g., on a light pole in a residential neighborhood) and the equipment  12   c  is shown deployed at a roadside area (e.g., on a roadside power pole). The equipment  12   c  could also be installed at other locations such as tunnels, canyons, coastal areas, etc. In one example, the equipment  12   b ,  12   c  can define wireless coverage areas such as microcells or picocells (i.e., cells each having a coverage area equal to or less than about 200 meters wide). The equipment  12   d  is shown deployed at a campus location (e.g., a university or corporate campus), the equipment  12   e  is shown deployed at a large public venue location (e.g., a stadium), and the equipment  12   f  is shown installed at an in-building or near-building environment (e.g., multi-dwelling unit, high rise, school, etc.). In one example, the equipment  12   d ,  12   e , and  12   f  can define wireless coverage areas such as microcells, picocells, or femtocells (i.e., cells each having a coverage area equal to or less than about 10 meters wide). 
     The wireless coverage area defining equipment  12  are often located in areas without power outlets conveniently located. As noted above, the hybrid cable  20  provides both power and data to the equipment  12 .  FIG.  2    is a transverse cross-sectional view taken through an example of one of the hybrid cables  20  of  FIG.  1   . Hybrid cable  20  includes an outer jacket  200  having a transverse cross-sectional profile that defines a major axis  202  and a minor axis  204 . The outer jacket has a height H measured along the minor axis  204  and a width W measured along the major axis  202 . The width W is greater than the height H such that the transverse cross-sectional profile of the outer jacket  200  is elongated along the major axis  202 . 
     The outer jacket  200  can include a left portion  206 , a right portion  208  and a central portion  210 . The left portion  206 , the right portion  208  and the central portion  210  can be positioned along the major axis  202  with the central portion  210  being disposed between the left portion  206  and the right portion  208 . The left portion  206  can define a left passage  212 , the right portion  208  can define a right passage  214  and the central portion  210  can define a central passage  216 . The passages  212 ,  214  and  216  can have lengths that extend along a central longitudinal axis  218  of the cable  20  for the length of the cable. A left electrical conductor  220  is shown positioned within the left passage  212 , a right electrical conductor  222  is shown positioned within the right passage  214  and at least one optical fiber  224  is shown positioned within the central passage  216 . Certain embodiments include from 1 to 12 fibers  224 , for example. The left electrical conductor  220 , the right electrical conductor  222  and the optical fiber  224  have lengths that extend along the central longitudinal axis  218  of the cable  20 . 
     Still referring to  FIG.  2   , the hybrid cable  20  includes a left pre-defined tear location  226  positioned between the central portion  210  and the left portion  206  of the outer jacket  200 , and a right pre-defined tear location  228  positioned between the central portion  210  and the right portion  208  of the outer jacket  200 . The left pre-defined tear location  226  is weakened such that the left portion  206  of the outer jacket  200  can be manually torn from the central portion  210  of the outer jacket  200 . Similarly, the right pre-defined tear location  228  is weakened such that the right portion  208  of the outer jacket  200  can be manually torn from the central portion  210  of the outer jacket  200 . The left pre-defined tear location  226  is configured such that the left portion  206  of the outer jacket  200  fully surrounds the left passage  212  and the central portion  210  of the outer jacket  200  fully surrounds the central passage  216  after the left portion  206  of the outer jacket  200  has been torn from the central portion  210  of the outer jacket  200 . In this way, the left electrical conductor  220  remains fully insulated and the optical fiber  220  remains fully protected after the left portion  206  has been torn from the central portion  210 . The right pre-defined tear location  228  is configured such that the right portion  208  of the outer jacket  200  fully surrounds the right passage  214  and the central portion  210  of the outer jacket  200  fully surrounds the central passage  219  after the right portion  208  of the outer jacket  200  has been torn from the central portion  210  of the outer jacket  200 . In this way, the right electrical conductor  222  remains fully insulated and the optical fiber  224  remains fully protected after the right portion  208  has been torn from the central portion  210 . 
       FIG.  3    shows the hybrid cable  20  with both the left portion  206  and the right portion  208  torn away from the central portion  210 . In this configuration, both the left electrical conductor  220  and the right electrical conductor  222  are fully insulated by their corresponding left and right portions  206 ,  208 . Additionally, the central portion  210  has a rectangular transverse cross-sectional shape that fully surrounds the central passage  216  so as to protect the optical fiber or fibers  224 . 
     It will be appreciated that the left and right electrical conductors  220 ,  222  have a construction suitable for carrying electricity. It will be appreciated that the electrical conductors can have a solid or stranded construction. Example sizes of the electrical conductors include 12 gauge, 16 gauge, or other sizes. 
     The outer jacket  200  is preferably constructed of a polymeric material. In one example, the hybrid cable  20  and the outer jacket  200  are plenum rated. In certain examples, the outer jacket  200  can be manufactured of a fire-retardant plastic material. In certain examples, the outer jacket  200  can be manufactured of a low smoke zero halogen material. Example materials for the outer jacket include polyvinyl chloride (PVC), fluorinated ethylene polymer (FEP), polyolefin formulations including, for example, polyethylene, and other materials. 
     The central passage  216  can contain one or more optical fibers  224 . In certain examples, the optical fibers  224  can be coated optical fibers having cores less than 12 microns in diameter, cladding layers less than 240 microns in diameter, and coating layers less than 300 microns in diameter. It will be appreciated that the core and cladding layers typically include a silica based material. In certain examples, the cladding layer can have an index of a refraction that is less than the index of refraction of the core to allow optical signals that are transmitted through the optical fibers to be confined generally to the core. It will be appreciated that in certain examples, multiple cladding layers can be provided. In certain examples, optical fibers can include bend insensitive optical fibers having multiple cladding layers separated by trench layers. In certain examples, protective coatings (e.g., a polymeric material such as actelate) can form coating layers around the cladding layers. In certain examples, the coating layers can have diameters less than 300 microns, or less than 260 microns, or in the range of 240 to 260 microns. In certain examples, the optical fibers  224  can be unbuffered. In other examples, the optical fibers can include a tight buffer layer, a loose buffer layer, or a semi-tight buffer layer. In certain examples, the buffer layers can have an outer diameter of about 800 to 1,000 microns. The optical fibers can include single mode optical fibers, multi-mode optical fibers, bend insensitive fibers or other fibers. In still other embodiments, the optical fibers  224  can be ribbonized. 
     As shown at  FIG.  4   , the left and right portions  206 ,  208  can be trimmed relative to the central portion  210  after the left and right portions  206 ,  204  have been torn away from the central portion  210 . In this configuration, the central portion  210  extends distally beyond the ends of the left and right portions  206 ,  208 . In certain examples, insulation displacement connectors can be used to pierce through the jacket materials of the left and right portions  206 ,  208  to electrically connect the left and right electrical connectors  220 ,  222  to an electrical power source, ground, active components or other structures. It will be appreciated that the optical fibers  224  can be connected to other fibers with mechanical or fusion splices, or directly terminated with optical connectors. In other examples, connectorized pigtails can be spliced to the ends of the optical fibers  224 . 
     Referring back to  FIG.  2   , the outer jacket  200  includes a top side  230  and a bottom side  232  separated by the height H. As depicted, the top and bottom sides  230 ,  232  are generally parallel to one another. Each of the left and right pre-defined tear locations  226 ,  228  includes an upper slit  234  that extends downwardly from the top side  230 , a lower slit  236  that extends upwardly from the bottom side  232  and a non-slitted portion  238  positioned between the upper and lower slits  234 ,  236 . In one example embodiment, the upper and lower slits  234 ,  236  are partially re-closed slits. In the depicted embodiment, the left and right pre-defined tear locations  226 ,  228  also include jacket weakening members  240  that are imbedded in the non-slitted portions  238 . By way of example, the jacket weakening members  240  can include strands, monofilaments, threads, filaments or other members. In certain examples, the jacket weakening members  240  extend along the central longitudinal axis  218  of the cable  20  for the length of the cable  20 . In certain examples, the jacket weakening members  240  are aligned along the major axis  202 . In certain examples, the upper and lower slits  230 ,  236  as well as the jacket weakening member  240  of the left pre-defined tear location  226  are aligned along a left tearing plane PL that is oriented generally perpendicular relative to the major axis  202 . Similarly, the upper and lower slits  234 ,  236  as well as the jacket weakening member  240  of the right pre-defined tear location  228  are aligned along a right tearing plane PR that is oriented generally perpendicular with respect to the major axis  202 . 
     Referring again to  FIG.  2   , the hybrid cable  20  can include a tensile strength structure  242  that provides tensile enforcement to the hybrid cable  20  so as to prevent tensile loads from being applied to the optical fibers  224 . In certain embodiments, the tensile strength structure  242  can include reinforcing structures such as Aramid yarns or other reinforcing fibers. In still other embodiments, the tensile strength structure  242  can have an oriented polymeric construction. In still other examples, a tensile strength structure  242  can include a reinforcing tape. In certain examples, the reinforcing tape can be bonded to the outer jacket  200  so as to line the central passage  216 . In certain examples, no central buffer tube is provided between the optical fibers  224  and the tensile reinforcing structure  242 . In certain examples, the tensile strength structure  242  can include a reinforcing tape that extends along the length of the hybrid cable  20  and has longitudinal edges/ends  244  that are separated so as to define a gap  244  therein between. In use, the tensile strength member  242  can be anchored to a structure such as a fiber optic connector, housing or other structure so as to limit the transfer of tensile load to the optical fibers  224 . It will be appreciated that the tensile strength structure  242  can be anchored by techniques such as crimping, adhesives, fasteners, bands or other structures. 
       FIG.  5    shows an alternative hybrid cable  20 ′ having the same construction as the hybrid cable  20  except two tensile strength structures  242 A,  242 B have been provided within the central passage  216 . Tensile strength members  242 A,  242 B each include a tensile reinforcing tape that is bonded to the central portion  210  of the outer jacket  200 . The tensile strength members  242 A,  242 B can include portions that circumferentially overlap one another within the central passage  216 . In certain examples, by stripping away an end portion of the central portion  210 , the tensile strength structures  242 A,  242 B can be exposed and readily secured to a structure such as a fiber optic connector, a panel, a housing or other structure. In one example, the tensile strength structures  242 A,  242 B can be crimped, adhesively secured or otherwise attached to rods (e.g., epoxy rods reinforced with fibers) that are in turn secured within a ruggedized fiber optic connector such as the fiber optic connector disclosed at U.S. Pat. No. 7,744,288 which is hereby incorporated by reference in its entirety, or the fiber optic connector disclosed at U.S. Pat. No. 7,918,609, which is hereby incorporated by reference in its entirety. 
     As noted above, the electrical conductors  220 ,  222  could be 12 gauge (AWG) or 16 gauge, for example. In certain examples, a 12 gauge conductor  220 ,  220  provides up to 1175 meter reach at 15 W, and a 750 meter reach for 25 W devices. The 16 gauge implementations can provide reduced cost for shorter reach applications or lower power devices, for example. 
     Providing power to remote active devices such as the wireless coverage area defining equipment  12  is often difficult and expensive. Providing required power protection and backup power further complicates powering such remote devices. Optical Network Terminals (ONT&#39;s) and Small Cell devices (such as picocells and metrocells) have “similar” power requirements. For example, 25 W, 12 VDC or 48 VDC devices are common, although variations occur.  FIG.  6    conceptually illustrates an example of a communication signal and power distribution system  300  in accordance with aspects of the present disclosure. Among other things, the system  300  provides a simple, “universal” connection of the optical fiber  224  and electrical conductors  220 ,  222  of the hybrid cable  20  to the equipment  12 . 
     The system  300  includes a fiber patch panel  302  that terminates optical fibers carrying signals to be distributed to the desired wireless coverage area defining equipment  12  via the optical fibers  224  of the hybrid cables  20 . A power supply  304  connects to the conductors  220 ,  222  of the desired hybrid cable  20 . In some examples, the power supply  304  receives 120/220 VAC and provides 48 VDC nominal. In some embodiments, the fiber patch panel  302  and power supply  304  are rack mounted. 
     A first end  306  of the hybrid cable  20  is connected to the appropriate optical fibers from the fiber patch panel  302  and to the power supply  304 . A second, distant end  308  of the cable  20  is connected to an interface device  310 . The interface device is connected to the wireless equipment  12 , either directly or through a media converter  312 . Examples of the interface  310  provide simplified termination of the hybrid cable  20 , allowing factory or field installation. In some embodiments, a DC-DC converter provides the desired voltage level for the particular device  12  to which it is connected and compensates for IR loss across variable link lengths. 
       FIGS.  7 - 13    illustrate various views of embodiments of the interface device  310 . The interface device  310  includes a body  320  having an exterior  322  and an interior  324 . A cover  326  is connected to the body  320  by a hinge  328  such that the interface device  310  can be opened to expose the interior  324  for access by an operator. A mounting bracket  340  extends from the body  320  for mounting the interface device  310  as desired using screws or bolts, for example. In one example, the interface device  310  defines footprint dimensions of about 55 mm×125 mm×190 mm. 
     A cable clamp  342  cooperates with the body  320  to fix the hybrid input cable  20  and an output cable  344  to the interface device  310  at a cable inlet  350  and a cable outlet  352 , respectively. As noted above, the hybrid cable  20  includes electrical conductors  220 ,  220  for supplying power to the interface device  310 , and ultimately the remote device  12 . In the illustrated examples, the interface device  310  includes an insulation displacement connector (IDC)  360  situated in the interior  324  of the interface device body  320  for connecting the conductors  220 ,  220  to the interface device  310 . Generally, an IDC (also sometimes referred to as insulation displacement termination and insulation piercing connector) is an electrical connector that connects to one or more conductors of an insulated conductor by a connection process that forces a selectively sharpened blade or blades through the insulation to contact the conductor, eliminating the need to strip the insulation before connecting. Further, the connector blades cold weld to the conductors to form a gas-tight connection. 
       FIGS.  9  and  10    illustrate the IDC  360  in closed and open positions, respectively. As shown in  FIG.  3    and discussed in conjunction therewith above, the hybrid cable  20  is configured such that the left portion  206  and the right portion  208  can be torn away from the central portion  210 . In this configuration, both the left electrical conductor  220  and the right electrical conductor  222  are fully insulated by their corresponding left and right portions  206 ,  208 . Referring to  FIG.  10   , the IDC  360  includes a housing  358  with first and second conductor grooves  362 ,  364  positioned on either side of a fiber pass-through groove  366 . Correspondingly, the electrical conductors  220 ,  222  of the hybrid cable  20  are situated on either side of the central portion  210  containing the optical fibers  224 . 
     The conductors  220 ,  222  are received by the corresponding conductor grooves  362 ,  364 , and insulator clamping ribs  368  are situated to press against the jacket  200  to hold the hybrid cable  20  in place. The IDC  360  includes a cover  370  hingedly connected to the housing  358  that when closed presses IDC terminals  372  against the conductors  220 ,  222  and through the left portion  206  and the right portion  208  of the outer jacket  200  to make an electrical connection with the conductors  220 ,  222 . The illustrated IDC terminals  372  are angled to provide a gas-tight connection. In the illustrated example, the left and right portions  206 ,  208  are trimmed such that the conductors  220 ,  222  extend beyond the IDC terminals  372  but remain within the housing  358  of the IDC  360 . 
     In other embodiments, the IDC is configured in a “pass-through” power arrangement, wherein the terminals  372  pierce the left and right portions  206 ,  208  to contact the conductors  220 ,  222 , but the left and right portions  206 ,  208  are not trimmed so they extend through the IDC  360  to be routed to equipment  12  or another interface device  310 , such as via the cable outlet  352 . 
     In the illustrated example, a power converter  376 , such as a DC-DC voltage converter, is situated in the interior  324  of the base  320  and electrically connected to the IDC  360  so as to electrically connect the conductors  220 ,  220  of the hybrid cable  20  to the power converter  376  via the IDC  360 . Thus, power entering the interface device  310  via the hybrid cable  20  can be conditioned and/or converted to the desired level for the wireless coverage area defining equipment  12  to which the interface device  310  connects. The power converter  376  is connectable to the output cable  344  to route the conditioned/converted power from the interface device  310  to the desired wireless equipment  12 . For instance, conductors of the output cable  344  could connect directly to the power converter  376  using screw terminals  378  thereon. In alternative embodiments, the power converter  376  can be omitted or bypassed if the power received by the interface device  310  is appropriate for the particular end device  12 . Further power connection arrangements are discussed herein below. 
     The optical fibers  224  from the hybrid cable  20  are received by the centrally positioned fiber pass-through groove  366  to route the optical fibers  224  through the housing  358  of the IDC  360 . The fibers  224  extend from the housing  358  and are routed along the perimeter of the interior  324  of the interface device  310 . In some embodiments, the optical fibers  324  are routed through the interior  324  directly to the cable outlet  352 , along with a separate power output cable. More typically, the fibers  324  would be routed to a fiber management device  380 . In the illustrated example, fiber guides  374  are situated in the corners of the interior  324  for routing the optical fibers  324  in the interface device while maintaining a desired bend radius. In certain implementations, the optical fibers  324  are thus received at the cable inlet  350 , routed through the IDC housing  358  and the interior  324  of the interface device body  320  to the fiber management device  380 . 
       FIGS.  11  and  12    illustrate an example of the interface device  310  wherein the fiber management device  380  includes an optical splice device for making a mechanical or fusion splice, for example. The illustrated fiber management device  380  thus includes furcation tubes  382  situated on splice holders  384 . In other implementations, other fiber optic management devices such as fiber optic connectors are provided. A strength member termination  386  is further provided in the embodiment illustrated in  FIGS.  11  and  12   . The optical fibers  224  can thus be spliced, for example, to a fiber optic pig tail and routed to the cable outlet  352 . In some examples, the output cable  244  is also a hybrid cable including optical fibers that are spliced to the fibers  224  using the fiber management device  380 , and conductors that receive power from the power converter  376 . 
       FIG.  13    illustrates another embodiment where the fiber management device  380  includes a media board  390  that converts optical signals received via the optical fibers  224  to electrical signals. A fiber optic connector  392 , such as an LC duplex input connector, is connected to the media board  390  to terminate the optical fibers routed through the interior  324  of the interface device  310  and receive optical signals therefrom. The media board  390  is electrically connected to the IDC  360 , either directly, or as in the illustrated embodiment, via the power converter  376 . In this manner, the media board is powered by power from the conductors  220 ,  222  terminated by the IDC  360 . Additionally, in some embodiments, the media board  390  connects output power and electrical communication signals to a power over Ethernet (PoE) connection. In such embodiments, the output cable  344  is a standard RJ-45 data/power cable that connects to a PoE jack  394  on the media board  390 . The RJ-45 cable can then be connected to the desired wireless coverage area defining equipment  12  to provide both communication signals and power thereto. 
     Some embodiments, for example, include 12 fibers  224  situated in the central passage  216 . Typically, two optical fibers  224  are terminated in a given interface device  310 . Since the two fibers  224  carrying signals for the desired wireless equipment  12  are to be terminated in the interface device  310 , they are cut downstream of the interface device  310 . A slit can be cut in the central portion  216  providing an opening through which the desired fibers  224  can be pulled from the central portion and routed to the fiber management device  380 . The remaining optical fibers  224  remain intact within the central portion  216 , and can be passed through the interface device  310  to another device, for example. 
     The power converter  276  provides DC/DC conversion, for example, as well as other power management functions such as circuit overload protection, mains cross protection, lightning protection, etc. In one particular embodiment, a 30 W, 12V output DC-DC converter from CUI Inc. of Tualatin, Oreg. (P/N VYC30 W-Q48-S12-T) is used. Other DC-DC converters may be employed based on electrical requirements, packaging, etc. In some implementations, a conditioning circuit is integrated into the interface  310  to minimize voltage ripple.  FIG.  14    shows an example of a typical conditioning circuit  400 . In further examples, overvoltage protection, such as a gas-tube, is incorporated between the IDC terminals and DC-DC converter input. 
     Referring back to  FIG.  6   , the fiber patch panel  302  can receive can receive optical signals from a remote location via a fiber optic trunk cable. Optical fibers of the trunk cable  110  can be separated at a fan-out device, or optical power splitters or wavelength division multiplexers can be used to split optical communications signals from the trunk cable to multiple optical fibers. The fibers can be routed to the patch panel  302 , and then to a desired one of the hybrid cables  20 , along with electrical power from the power supply  304 . In one example, the power supply  304  receives 120 volt or 220 volt alternating current. In one example, power supply  302  includes an AC/DC converter that converts the electrical power from alternating current to direct current. The power supply  304  converts the electrical power from the first voltage (e.g., 120 v or 220 v) to a second voltage that is less than the first voltage. In one example, the second voltage is less than or equal to 60 volts and 100 Watts such that the output voltage complies with NEC Class II requirements. 
     The hybrid cable  20  can be used to transmit electrical power and optical communication signals from the fiber patch panel  302  and power supply  304  located at a first to the wireless equipment  12  located at a second location. The first end  306  of the hybrid cable  20  can include a first interface for connecting the hybrid cable to electrical power and fiber optic communication at a connector, and the second end  308  of the hybrid cable  20  is received at the cable inlet  350  of the interface device  310 . The power converter  376  of the interface device  310  converts electrical power carried by the hybrid cable  20 , for example, to a direct current third voltage that is less than the second voltage. In one example, the third voltage corresponds to an electrical voltage requirement of the device  12 . In one example, the third voltage is 12V, 24V or 48V. 
     In some implementations, a converter  312  is associated with the equipment  12  for converting optical signals to electrical signals. In such implementations, the optical fibers and power are provided from the interface device  310  to the converter  312 , which provides power and communication signals to the equipment  12 . In other implementations, the interface device  310  converts the optical signals to electrical signals using the media board  390 , and provides power and electrical communication signals to the equipment  12 . 
     Aspects of the present disclosure relate to powered fiber cable systems capable of simultaneously powering and communicating with wireless coverage area defining equipment (e.g., transceivers, wireless routers, WiFi access points/WiFi hot spots, small cell devices, or like devices). The powered fiber cable system can also be used to power and communicate with other devices such as digital signage, high definition surveillance cameras, and like devices. Moreover, powered fiber cable systems in accordance with the principles of the present disclosure can be incorporated into fiber optic networks (e.g., fiber-to-the-home (FTTH), fiber-to-the-premises (FTTP, fiber-to-the-anything (FTTX)) to provide back-up power or primary power to optical network terminals (ONT) including electronics for providing optical-to-electrical conversion at or near a subscriber location. By providing back-up power using a powered fiber cable system in accordance with the principles of the present disclosure, battery back-ups at the optical network terminals can be eliminated. Powered fiber cable systems in accordance with the principles of the present disclosure are particularly well suited for supporting active devices at outdoor locations where power is not readily available. However, powered fiber cable systems in accordance of the principles of the present disclosure can also be used to support indoor applications such as in local area networks where power and fiber are provided to desk-top locations (e.g., fiber-to-the-desk (FTTD)). Other applications for powered fiber cable systems in accordance with the principles of the present disclosure relate to power-over-Ethernet extensions (PoE or PoE+). 
     Aspects of the present disclosure relate to systems that provide a “rack to device” vision for both powering and communicating with active devices such as small cell devices, ONT&#39;s, WiFi hot spots, digital signage, surveillance cameras or like devices in one cable system.  FIG.  15    shows an example powered fiber cable system  400  in accordance with the principles of the present disclosure. The powered fiber cable system  400  includes a rack  402  positioned at a location where power (e.g., a power system\grid that typically provides AC power such as a mains power system) and fiber network are available. Such locations where power and fiber optic network communications are available can be referred to as head ends. In certain examples, the power locations (i.e., head ends) can be co-located at a cell site base station, a base station on a building top, in a telecom closet or data center or anywhere where power and access to a fiber optic network are available. As shown at  FIG.  15   , a patch panel  404  is mounted on the rack  402 . The patch panel  404  is coupled to a fiber optic network. For example, optical fibers optically corresponding to fiber optic distribution or feed cables can be connectorized and plugged into fiber optic adapters supported at the patch panel  404 . The rack  402  is also shown supporting a power supply unit  406  that in certain examples provides a DC output of 48 volts or less. 
     In one example, the power supply can include a power express class II power converter shelf manufactured by General Electric. The power supply can include and AC/DC transformer for transforming alternating current (AC) from a mains power supply into DC power for distribution to remotely located active devices. In certain examples, the power supply  406  can power up to 32 hybrid cables  20  in a modular design with four modules and eight cables per module. In certain examples, the power supply is configured to output relatively low voltage DC current (e.g., less than or equal to 48 volts DC). In certain examples, the power source is National Electric Code (NEC) class 2 (as specified by Article 725) and Safety Extra Low Voltage (SELV) compliant. In certain examples, the voltage between any two conductors should not exceed 60 volts DC under normal operating conditions. In certain examples, the power supply is limited to 100 VA. Such low voltage circuits are advantageous because electricians are not required to install such systems, such systems are inherently safe because of the low voltage limits, and such systems can be installed in a conduit-free manner. In certain examples, the power supply can also include circuit protection electronics such as gas discharge tubes, metal oxide varistor components and transient voltage suppression structures/diodes. 
     As shown at  FIG.  15   , the patch panel  404  and the power supply  406  are both rack mounted. Optical communication lines from the patch panel  404  and power lines from the power source  406  are coupled to hybrid cables  20  routed to universal interface devices  310  that support active devices such as a picocell  408 , a metrocell  410 , a femtocell  412  and an ONT  414 . The ONT  414  is shown connected to the corresponding interface device  310  by a power line  415  and a separate fiber line  417 . The picocell  408 , metrocell  410  and femtocell  412  are coupled to their corresponding interface devices  310  by power lines  419  and two fiber lines  421 ,  423 . In other examples, the fiber lines  421 ,  423  can be replaced with twisted pair conductors for carrying electrical signals in cases where optical to electrical signal conversion occurs at the interface device  310 . 
     Further aspects of the present disclosure relate to a remote interface device (e.g., interface device  310  that is remote from the power supply) for providing an interface between a hybrid cable and a remote active device, the interface device including a closure that houses circuitry for providing electrical power management and including circuit protection electronics. It will be appreciated that the circuitry within the closure is adapted for providing an effective interface between a hybrid cable (e.g., hybrid cable  20 ) and a remote active device. In certain examples, the closure is designed for outdoor environmental use and includes an environmentally sealed construction. In certain examples, the electrical power management circuitry eliminates the need for line power system design. For example, the electrical power management circuitry can include a DC-to-DC converter suitable for converting power carried by one of the hybrid cables  20  to a voltage and power level compatible with an active device intended to be powered with power from the hybrid cable  20 . In certain examples, the DC-to-DC converter can increase the voltage of the power carried by the hybrid cable  20  to a level compatible with the active device powered by the hybrid cable. In certain examples, the increase in voltage provided by the DC-to-DC converter compensates for voltage loss that may occur over the length of the hybrid cable. In certain examples, the DC-to-DC converter raises the voltage level to 12 volts, 24 volts or 48 volts. In certain other examples, the DC-to-DC converter decreases the voltage level to a level compatible with the active device intended to be powered by the hybrid cable. In certain examples, the power is converted so as to become compatible with a 25 watt device, a 30 watt device, or a 45 watt device. In certain examples, the closure also houses an optical-to-electrical converter that converts optical signals from the hybrid cable to electrical signals that are transmitted to the active device. In certain examples, the electrical signals and the power can be transmitted from the interface device to the active device by a twisted pair Ethernet cable so as to provide power-over-Ethernet or power-over-Ethernet-plus connectivity. 
     As indicated above, the closure of the interface device can enclose circuit protection electronics. For example, the circuit protection electronics can include primary electrical protection that may include a gas discharge tube rated to at least 40 kAmp surge/overvoltage protection. Such structure can provide protection with respect to lightning strikes and line cross-overs. The electrical protection can also include secondary electrical protection that may be rated to 4.5 kAmp and that may include metal oxide varistor components that couple to ground in response to voltage surges. The electrical protection may also include tertiary protection that prevents voltage from rising above a predetermined level (e.g., 80 volts, or 100 volts). In certain examples, the tertiary protection can include a transient voltage suppression diode. In certain examples, fast acting fuses can be used. 
     Cables in accordance with the principles of the present disclosure can provide power over relatively long distances. For example, using 12 gauge conductors in the hybrid cable and using conversion circuitry in the interface device that converts the optical signals and power to a PoE format, the system can provide 10 Watts of power over a length of 3,000 meters, 15 Watts of power over 2,400 meters, 20 Watts of power over 1,900 meters and 25 Watts of power over 1,600 meters. If power is provided in a non-power over Ethernet format (e.g., via an M8 plug or other power lines separate from the communications lines), 30 watt power can be provided up to 1,600 meters and 45 watt power can be provided up to 1,000 meters. A system that utilizes 16 gauge conductors and outputs power in a power over Ethernet format can provide 10 watts of power at 1,200 meters, 15 watts of power at 960 meters, 20 watts of power at 760 meters, and 25 watts of power at 640 meters. By not using a power over Ethernet format and instead keeping the power separate from the communications via a separate power line, the 16 gauge wire can provide 30 watts of power at 640 meters and 45 watts of power at 400 meters. 
     Aspects of the present disclosure relate to interface closures that can be readily customized to meet customer requirements. In certain examples, the closures can be environmentally sealed and can include clamps for clamping hybrid cables such as the hybrid cable  20 . The closures can also include power management circuitry such as power converters (e.g., DC-to-DC power converters). The power converters can be customized to comply with the power requirements of the remote device intended to be powered by the customer. In certain examples, the power conversion circuitry can be modular and modules providing different levels of conversion can be selected and plugged into the circuit board of the closure to satisfy the customer requirement. For example, power converters capable of outputting 12, 24 or 48 volts can be used. It will be appreciated that the format of the power output from the interface closure can also be customized to meet customer needs. For example, the interface closure can be configured to output power and communications over a variety of formats such as: (a) power-over-Ethernet; (b) power-over-Ethernet-Plus; (c) separate power (e.g., via a cable terminated with an M8 plug or other configuration) and Ethernet lines (e.g., terminated with RJ45 connectors or other connectors); (d) separate fiber lines for communications and power lines for power (e.g., terminated with M8 connectors or other power connectors); (e) a hybrid cable having optical fibers for optical signals and electrical conductors for power that can be terminated with a hybrid connector or can have separate fiber and power pigtails; or (f) a cable having twisted pair conductors for carrying communication signals and separate electrical conductors for power that can be terminated by separate RJ-style connectors for communication signals and an M8 plug for power or other connector arrangements. In the case where separate fiber lines are used, the fiber lines can be terminated with different styles of fiber optic connectors such as LC connectors, SC connectors, or other fiber optic connectors. In certain examples, the fiber optic connectors can be ruggedized and can include environmental sealing as well as twists-to-lock fastening elements such as threaded fasteners or bayonet-style fasteners. In the case of Ethernet cable, standard RJ-45 connectors or ruggedized RJ-45 connectors can be used. For pigtails carrying only power, stranded or solid conductors can be used. Additionally, the power pigtails can be terminated with power connectors such as M8 connectors. 
       FIG.  16    shows a cable system  100  that can be used to transmit power and communications from a first location  102  to an active device  104  at a second location  106 . The second location  106  is remote from the first location  102 . In certain example, the first location  102  can be a base location and the active device  104  can include wireless coverage area defining equipment. Examples of wireless coverage area defining equipment and locations where such equipment may be installed are described above. Examples of other types of active devices include cameras such as high definition video cameras. 
     The first location  102  receives optical signals from a remote location  108  via a fiber optic trunk cable  110 . Optical fibers of the trunk cable  110  can be separated at a fan-out device  111  at the first location. Alternatively, optical power splitters or wavelength division multi-plexers can be used to split optical communications signals from the trunk cable  110  to multiple optical fibers. The fibers can be routed to a patch panel  112  having fiber optic adapters  114  (i.e., structures for optically and mechanically interconnecting two fiber optic connectors  115 ). The first location  102  can also include a combined power/communication panel  116  having fiber optic adapters  117  paired with power adapters  118  (i.e., ports). Connectorized fiber optic patch cords  120  can be routed from the fiber optic adapters  114  to the fiber optic adapters  117 . 
     The first location  102  can receive electrical power from a main power line  122 . In one example the main power line  122  can be part of a mains power system that provides 100-240 nominal volt alternating current (example frequencies include 50 and 60 Hertz). The first location  102  can include a converter  124  for converting the electrical power from the first voltage (e.g., 100 v, 120 v, 220 v, 230 v, 240 v etc. nominal voltage) to a second voltage that is less than the first voltage. In one example, the second voltage is less than or equal to 60 volts and less than or equal to 100 Watts such that the output voltage complies with NEC Class II requirements. In one example, the converter  124  is an AC/DC converter that converts the electrical power from alternating current to direct current. Connectorized power cords  126  can be used to route electrical power having the second voltage from the converter  124  to the power adapters  118 . In certain examples, the combined power/communications panel  116  can include at least 18, 24, 30 or 32 fiber optic adapters paired with corresponding power adapters  118 . In certain examples, the converter  124  is large enough to provide NEC Class II compliant power through separate hybrid cables to at least 18, 24, 30 or 32 active devices. Of course, converter having smaller capacities could be used as well. Additionally, the converter  124  can be part of a voltage conversion package including overvoltage protection that provides protection/grounding in the event of lightning strikes and main crosses. 
     A hybrid cable  20  can be used to transmit electrical power and optical communication signals between the first and second locations  102 ,  106 . The hybrid cable  20  can include an outer jacket  150  containing at least one optical fiber  152  for carrying the optical communication signals and electrical conductors  154  (e.g., wires such as ground and power wires) for transmitting the electrical power having the second voltage. The hybrid cable  20  can include a first end  156  and a second end  158 . The first end  156  can include a first interface for connecting the hybrid cable to electrical power and fiber optic communication at the first location  102 . In one example, the first interface can include a power connector  160  (e.g., a plug) that connects the electrical conductors  154  to one of the connectorized power cords  126  at the power/communications panel  116 . The power connector  160  can be plugged into the adapter  118  and can be provided at a free end of a cord that extends outwardly from the outer jacket  150  at the first end of the hybrid cable  20 . The cord can contain the electrical conductors  154 . The first interface can also include a fiber optic connector  162  (e.g., an SC connector, LC connector, ST-style connector or other type of connector) that connects the optical fiber  152  to one of the patch cords  120 . The fiber optic connector  162  can plug into one of the fiber optic adapters  117  and can be mounted at the free end of a cord that contains the optical fiber  152  and extends outwardly from the outer jacket  150  at the first end of the hybrid cable  20 . 
     The second end  158  of the hybrid cable  20  can include a second interface for connecting the hybrid cable  20  to the active device  104  such that electrical power is provided to the active device  104  and such that fiber optic communication signals can be transmitted between the first and second locations  102 ,  106 . The second interface includes an interface structure  164  including a power connection location  166  and a communication connection location  168 . In one example, the interface structure  164  includes a power converter  170  for converting electrical power carried by the hybrid cable  20  to a direct current third voltage that is less than the second voltage. In one example, the third voltage corresponds to an electrical voltage requirement of the active device  104 . In one example, the power converter  170  is a DC/DC converter. In one example, the third voltage is 12V, 24V or 48V. In examples where AC current is transmitted by the hybrid cable  20 , the power converter  124  can be an AC/AC converter and the power converter  170  can be an AC/DC converter. In certain examples, the interface structure  164  can include an optical-to-electrical converter for converting the communications signals carried by the optical fiber  152  from an optical form to an electrical form. In other examples, optical-to-electrical conversion can be performed by the active device  104  or can take place between the active device  104  and the interface structure  164 . 
     In one example, the interface structure  164  includes a converter interface that allows power converters  170  with different conversion ratios to interface and be compatible with the interface structure  164 . The conversion ratio of the particular power converter  170  used can be selected based on factors such as the voltage requirement of the active device  104  and the length of the hybrid cable  20 . The power converters  170  can have a modular configuration can be installed within the interface structure  168  in the field or in the factory. In one example, the power converters  170  can have a “plug-and-play” interface with the interface structure. The modular configuration also allows the power converter  170  to be easily replaced with another power converter  170 , if necessary. In certain examples, the interface structure  164  can include overvoltage protection and grounding arrangements such as fuses, metal oxide varistors, gas tubes or combinations thereof. 
     In one example, the electrical power having the third voltage can be output to the active device  104  through the power connection location  166 . The power connection location  166  can include a power connector, a power port, a power cord or like structures for facilitating connecting power to the active device  104 . In one example, the power connection location  166  can have a modular configuration that allows interface connectors having different form factors to be used. 
     In one example, the communications signals can be transferred between the hybrid cable  20  and the active device through the communication connection location  168 . The communication connection location  168  can include a connector, a port, a cord or like structures for facilitating connecting to the active device  104 . In one example, the communication connection location  168  can have a modular configuration that allows interface connectors having different form factors to be used. In the case where the optical to electrical converter is provided within the interface structure  164 , the connection location can include electrical communication type connectors (e.g., plugs or jacks) such as RJ style connectors. In the case where the optical to electrical converter is provided at the active device  104 , the communication connection location  168  can include fiber optic connectors and or fiber optic adapters (e.g., SC connectors/adapters; LC connectors/adapters, etc.). In certain examples, ruggedized, environmentally sealed connectors/adapters can be used (e.g., see U.S. Pat. Nos. 8,556,520; 7,264,402; 7,090,407; and 7,744,286 which are hereby incorporated by reference in their entireties. It will be appreciated that when the active devices include wireless transceivers, the active devices can receive wireless signals from the coverage area and such signals can be carried from the active devices to the base station  11  via the hybrid cables. Also, the active devices can covert signals received from the hybrid cables into wireless signals that are broadcasted/transmitted over the coverage area. 
     In one example, the second voltage is less than the first voltage and greater than the third voltage. The third voltage is the voltage required by the active device at the second location. In one example, the second voltage is sufficiently larger than the third voltage to account for inherent voltage losses that occur along the length of the hybrid cable. 
     Various modifications and alterations of this disclosure may become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the scope of this disclosure is not to be unduly limited to the illustrative examples set forth herein.