Abstract:
A premise wiring system comprises a backend communications system including telephony capabilities and at least one communications device configured for electrical signalling. A signal conversion system acts between the backend communications system and the at least one communications system. The signal conversion system converts electrical signalling being exchanged between the at least one communications device and the backend communications system into optical signalling for transmission over a fiber optic link and reconverts the optical signalling into electrical signalling for delivery to the at least one communications device and the backend communications system.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to communications and in particular to a fiber optic premise wiring system. The present invention also relates to a system for converting electrical signals to optical signals and back to electrical signals to enable communications devices configured for electrical communications to communicate over a fiber optic link.  
         BACKGROUND OF THE INVENTION  
         [0002]    Today&#39;s businesses rely significantly on communications and a variety of technologies to access, convey and process information. This need puts a premium on information technology that increases communications speed and bandwidth.  
           [0003]    It is well known that fiber optic cable provides significant advantages over its copper cable counterpart. Fiber optic cable has increased capacity and less signal degradation as compared to copper cable, requires less maintenance and is more difficult to tap into. Despite these advantages, most current information technology used for voice and data communications does not require the use of fiber optic cable to interconnect with communications devices, nor do suppliers of such information technology promote use of fiber optic cable. Copper cable manufacturers to-date have had a significant amount of success in improving communications over existing or slightly improved copper cable. As a result, copper cabling has not been a bottleneck in terms of communications speed and bandwidth and therefore, has not been a deciding factor in forcing a move from copper cable to fiber optic cable. Further, since current information technology generally does not require fiber optic cable for high or optimum performance and since applications that require fiber optic cable are limited, the push to move from copper cable to fiber optic cable has been limited notwithstanding the advantages associated with fiber optic cable discussed above.  
           [0004]    During construction of new facilities and renovations of older facilities, fiber optic backbones are often installed on the assumption that copper cabling will eventually be replaced with fiber optic cabling. In fact it is anticipated that within the next five (5) to ten (10) years, most communications systems will make use of fiber optic networks that bring fiber to the desk i.e. use fiber optic cable to interconnect communications devices to the backend supporting information technology.  
           [0005]    Installing fiber optic cable and components within a premise is a costly investment. These significant costs have made businesses hesitant to convert to fiber optic cable at this time. As will be appreciated, a need therefore exists for a cost effective solution to install fiber optic cable within premises to allow businesses to switch to fiber optic cable now so that they may enjoy the benefits associated with fiber optic cable while facilitating the switch when the change to fiber optic cable becomes necessary.  
           [0006]    It is therefore an object of the present invention to provide a novel fiber optic premise wiring system. It is also an object of the present invention to provide a novel system for converting electrical signals to optical signals and back to electrical signals to enable communications devices configured for electrical communications to communicate over a fiber optic link.  
         SUMMARY OF THE INVENTION  
         [0007]    According to one aspect of the present invention there is provided a signal conversion system for communications comprising:  
           [0008]    a front-end interface into which at least one communications device configured for electrical signalling is to be connected;  
           [0009]    a backend interface to be connected to a backend electrical signal based communications system; and  
           [0010]    a fiber optic link interconnecting said front-end and backend interfaces, wherein electrical signalling between a communications device connected to said front-end interface and a backend communications system connected to said backend interface is converted by said front-end and backend interfaces into optical signalling for transmission therebetween and is reconverted by said front-end and backend interfaces to electrical signalling for transmission to said communications device and backend communications system.  
           [0011]    Preferably, the front-end interface is designed to accommodate a plurality of different types of communications devices. In the preferred embodiment, the front-end interface includes a first subsystem having a series of jacks into which different communications devices are to be plugged and circuitry to support the jacks; and a second subsystem including a processor to process signals received from and destined to the communications devices, a switch to control signal flow, and at least one fiber optic transceiver to convert optical signals received from the fiber optic link into electrical signals and to convert electrical signals received from the processor into optical signals.  
           [0012]    The backend interface includes a third subsystem having a series of jacks into which the backend communications system is to be plugged and circuitry to support the jacks; and a fourth subsystem including a processor to process signals received from and destined to the communications devices, a switch to control signal flow and at least one fiber optic transceiver to convert optical signals received from the fiber optic link into electrical signals and to convert electrical signals received from the processor into optical signals.  
           [0013]    In a preferred embodiment, the switch of the front-end interface and the switch of the backend interface is an Ethernet switch. The front-end and backend interfaces communicate over the fiber optic link via an Internet protocol (IP) connection.  
           [0014]    It is also preferred that the first and second subsystems are modular and mounted on separate circuit boards within the front-end interface and that the third and fourth subsystems are modular and mounted on separate circuit boards within the backend interface. The separate circuit boards in the front-end and backend interfaces are preferably releasably connected via mating card connectors.  
           [0015]    According to another aspect of the present invention there is provided a premise wiring system comprising:  
           [0016]    a backend communications system including telephony capabilities;  
           [0017]    at least one communications device configured for electrical signalling; and  
           [0018]    a signal conversion system acting between said backend communications system and said at least one communications device, said signal conversion system converting electrical signalling being exchanged between said at least one communications device and said backend communications system into optical signalling for transmission over a fiber optic link and reconverting said optical signalling into electrical signalling for delivery to said at least one communications device and said backend communications system.  
           [0019]    The present invention provides advantages in that by coupling the communications devices to the backend communications system through fiber optic cable, space requirements for the same carrying capacity as compared with copper cable are reduced. Furthermore by using fiber optic cable to interconnect the communications devices and the backend communications system, communications capacity is increased, maintenance costs and electromagnetic/radio frequency interference (EMI/RFI) are reduced and security is increased due to the fact that it is more difficult to tap into fiber optic cable than copper cable. Also, by running fiber optic cable, safety is increased since the risk of electrical fire is removed.  
           [0020]    The present invention also provides advantages in that longer cable runs between communications devices and the backend communications system can be made without requiring signal amplification components resulting in lower wiring system costs. Also, in cases where the fiber optic cable is installed before it is necessary to convert to fiber optical cable, future conversion costs will be reduced when it becomes necessary to convert to fiber optic cable.  
           [0021]    The present invention provides further advantages in that since the fiber optic cable terminates either at wallboxes or surface mount boxes that provide high quality terminations, installation is facilitated. Also, since the subsystems within the front-end and backend interfaces are modular, they can be easily installed and replaced by technicians with minimal training. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0022]    Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which:  
         [0023]    [0023]FIG. 1 is a schematic illustration of a standard prior art copper premise wiring system within a building;  
         [0024]    [0024]FIG. 2 is a schematic illustration of a standard prior art combined copper and fiber optic premise wiring system within a building;  
         [0025]    [0025]FIG. 3 is a schematic illustration of a fiber optic premise wiring system within a building in accordance with the present invention;  
         [0026]    [0026]FIG. 4 is a schematic block circuit diagram of a signal conversion system including front-end and backend modular interfaces showing the interconnection between a wallbox and a backend communications system forming part of the fiber optic premise wiring system of FIG. 4;  
         [0027]    [0027]FIG. 5 is an enlarged schematic block circuit diagram of a portion of FIG. 4;  
         [0028]    [0028]FIG. 6 a  is a front elevation view of a wallbox forming part of the fiber optic premise wiring system of FIG. 4;  
         [0029]    [0029]FIG. 6 b  is a perspective view of the wallbox of FIG. 6 a;    
         [0030]    [0030]FIG. 7 a  is a perspective view of a surface mount box forming part of a fiber optic premise wiring system in accordance with the present invention;  
         [0031]    [0031]FIGS. 7 b  and  7   c  are front and rear elevation views respectively of the surface mount box of FIG. 7 a ; and  
         [0032]    [0032]FIG. 7 d  is a bottom plan view of the surface mount box of FIG. 7 a.   
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    The present invention relates generally to a fiber optic premise wiring system for communications such as for example voice, data, video etc. Fiber optic cable is used as the communications medium to interconnect communications devices such as telephones, facsimile machines and computer workstations to a backend communications system. To avoid investment in optical component upgrades, modular interfaces are provided between the communications devices and the fiber optic cable as well as between the fiber optic cable and the backend communications system that perform appropriate electrical signal to optical signal to electrical signal conversion. Preferred embodiments of the present invention will be described; however for ease of reference a brief discussion of a conventional copper premise wiring system and a conventional combined copper and fiber optic premise wiring system will firstly be made with reference to FIGS. 1 and 2.  
         [0034]    Turning now to FIG. 1, a multi-story building  10  wired with a standard prior art copper premise wiring system  12  to provide the building with communications facilities is shown. As can be seen, copper premise wiring system  12  includes a main telephone switch  14  that receives an incoming copper telecommunications cable  16  entering the building  10 . The telephone switch  14  is connected to a copper distribution cable  18  via a pair of patch panels  20   a  and  20   b . Runs of copper cable  22  are connected to the copper distribution cable  18  via patch panels  24   a  and  24   b  and terminate at jacks (not shown) positioned throughout the building  10 . Communications devices such as telephones  26  and facsimile machines  28  are connected to the jacks.  
         [0035]    An active computer network component  30  such as a server also receives an incoming copper telecommunications cable  32  entering the building  10 . Computer network component  30  is connected to other computer network components  34  positioned throughout the building  10  via a pair of patch panels  36   a  and  36   b  and a copper distribution cable  38 . Computer workstations  40  are connected to the computer network components  34  via runs of copper cable  42 . In this manner, the telephones  26 , facsimile machines  28  and computer workstations  40  communicate with a backend communications system over copper cable connections.  
         [0036]    [0036]FIG. 2 shows another multi-story building  50  wired with a standard combined copper and fiber optic premise wiring system  52  to provide the building with communications facilities. As can be seen, combined copper and fiber optic premise wiring system  52  similarly includes a main telephone switch  54  that receives an incoming copper telecommunications cable  56  entering the building  50 . The telephone switch  54  is connected to a copper distribution cable  58  via a pair of patch panels  60   a  and  60   b . Runs of copper cable  62  are connected to the copper distribution cable  58  via patch panels  64   a  and  64   b  and terminate at jacks (not shown) positioned throughout the building  50 . Telephones  66  and facsimile machines  68  are connected to the jacks.  
         [0037]    An active computer network component  70  such as a server receives an incoming fiber optic telecommunications cable  72  entering the building  50 . Computer network component  70  is connected to other computer network components  74  positioned throughout the building  50  via a pair of patch panels  76   a  and  76   b  and a fiber optic distribution cable  78 . Computer workstations  80  are connected to the computer network components  74  via runs of fiber optic cable  82 . In this manner, the telephones  66  and facsimile machines  68  communicate with a backend communications system over copper cable connections while the computer workstations  80  communicate with a backend communications system over fiber optic cable connections.  
         [0038]    Although the premise wiring systems  12  and  52  shown in FIGS. 1 and 2 adequately support communications at present, when the switch from copper cable to fiber optic cable becomes mandatory, the costs associated with converting these premise wiring systems fully to fiber optic cabling will be significant.  
         [0039]    To facilitate the future switch from copper cabling to fiber optic cable, the present fiber optic premise wiring system has been conceived. The costs to implement the present fiber optic premise wiring system are comparable with the costs associated with installing a conventional copper premise wiring system. The present fiber optic premise wiring system will however significantly reduce the costs to switch over to fiber optic cabling when it becomes mandatory to do so. Preferred embodiments of the present invention will now be described with particular reference to FIGS.  3  to  7   d.    
         [0040]    Turning to now to FIG. 3, a multi-story building  110  wired with a fiber optic premise wiring system  112  in accordance with the present invention to provide the building with communications facilities is shown. As can be seen, fiber optic premise wiring system  112 , similar to the premise wiring system of FIG. 1, includes a main telephone switch  114  that receives an incoming copper telecommunications cable  116  entering the building  110  and an active computer network component  118  such as a server that receives an incoming copper telecommunications cable  120 . The telephone switch  114  and active computer network component  118  are connected to a backend interface  122  via copper cables  124 . The backend interface  122  is connected to front-end interfaces  126  positioned throughout the building  110  via a fiber optic distribution cable  128 , pairs of patch panels  130   a  and  130   b  and runs of fiber optic cable  132 . Communications devices such as telephones  134 , facsimile machines  136  and computer workstations  138  are connected to the front-end interfaces  126 .  
         [0041]    The backend and front-end interfaces  122  and  126  respectively form a signal conversion system to convert electrical signals to optical signals and back to electrical signals to allow the communications devices to communicate with a backend communications system over fiber optic connections. The front-end interfaces  126  in this embodiment are accommodated within wallboxes  140  (see FIGS. 6 a  and  6   b ) housing an array of jacks designed to accommodate the various different types of communications devices. The telephones  134 , facsimile machines  136  and computer workstations  138  are plugged into the jacks of the wallboxes  140  via conventional copper terminal connections  142 . As will be appreciated, unlike the prior art premise wiring system  52  illustrated in FIG. 2, in the present fiber optic premise wiring system  112 , all communications devices are coupled to a backend communications system through fiber optic cable rather than through multiple cables handling voice and data separately. As a result, when it becomes necessary to switch fully to fiber optic communications, it is only necessary to modify the backend and front-end interfaces  122  and  126 , making the switch easy and affordable. The present invention also reduces the requirement for floor space allotted to communications closets.  
         [0042]    Referring now to FIGS. 4 and 5, a schematic block circuit diagram of the backend interface  122  and one of the front-end interfaces  126  is shown. The front-end interface  126  and backend interface  122  are coupled by a fiber optic link  146  forming part of the fiber optic cable run  132  and the fiber optic distribution cable  128 . In this particular embodiment, the fiber optic link  146  includes two fiber optic pairs  154  and  156 . Each fiber optic pair  154 ,  156  includes a transmit (Tx) fiber and a receive (Rx) fiber.  
         [0043]    The front-end interface  126  includes a pair of interconnected interface subsystems, namely a fiber optic premise interface (FOPI) subsystem  160  and a telephony device interface (TDI) subsystem  162 . The FOPI and TDI subsystems  160  and  162  are modular and are mounted on separate circuit boards. The two circuit boards are releasably connected through mezzanine circuit board card connectors  164  and  166  carried on the circuit boards.  
         [0044]    TDI subsystem  162  in the present embodiment includes an RJ45 analog telephone jack  170  to receive the copper terminal connection  142  from a standard analog telephone, and an RJ45 digital telephone jack  174  to receive the copper terminal connection  142  from a digital telephone. The analog telephone jack  170  is coupled to a coder/decoder (Codec)  176  via a high voltage (HV) protection circuit  178  and a subscriber line interface circuit (SLIC)  180 . The SLIC circuit  180  is also coupled to the tip and ring lines extending from the telecommunications power supply  182 . The Codec  176  is coupled to the mezzanine circuit board card connector  166  via a general circuit interface (GCI)  184 .  
         [0045]    The digital telephone jack  174  is also connected to the mezzanine circuit board card connector  166  via an HV protection circuit  186  and interface circuits  188  and  190  to interface with a backend digital telephone system. The interface circuits  188  and  190  may be memory mapped or include a GCI  184 .  
         [0046]    FOPI subsystem  162  includes a central processing unit (CPU)  200  running an embedded Linux operating system. CPU  200  includes a main processor  202 , flash read only memory (ROM)  204 , dynamic random access memory (DRAM)  206 , a debug serial port  208  and a debug Ethernet port  210 . The main processor  202  is coupled to the mezzanine circuit board card connector  164  via a GCI  212 . When the mezzanine circuit board card connectors  164  and  166  matingly engage, the GCIs  184  and  212  are interconnected. The GCIs  184  and  212  provide a framed communications facility between the Codec  176  and the CPU  200 .  
         [0047]    The main processor  202  is also connected to a reset supervisor  220  and to an Ethernet switch  222  via a media access control (MAC) interface  224  and a serial peripheral interface (SPI)  226 . The Ethernet switch  222  provides output to a bank of status indicators in the form of light emitting diodes (LEDs)  230  and is connected to a configuration electrically erasable programmable read only memory (EEPROM)  232 , a pair of fiber optic transceivers  234  and  236 , and three 10/100 BaseT transceivers  238 . Each 10/100 BaseT transceiver  238  includes an RJ45 10/100 BaseT Ethernet jack  242 , an HV protection circuit  244  and a magnetic circuit  246 . The fiber optic transceivers  234  and  236  are each coupled to a respective one of the fiber optic pairs  154  and  156 .  
         [0048]    The backend interface  122  also includes a pair of interconnected interface subsystems, namely a FOPI subsystem  260  and a telecommunications equipment interface (TEI) subsystem  262 . The FOPI and TEI subsystems are similarly modular and mounted on separate circuit boards that are releasably connected through mezzanine circuit board card connectors  264  and  266  carried on the circuit boards.  
         [0049]    The FOPI subsystem  260  of the backend interface  122  includes a CPU  300  running an embedded Linux operating system. The CPU  300  similarly includes a main processor  302 , flash ROM  304 , DRAM  306 , a debug serial port  308  and a debug Ethernet port  310 . The main processor  302  is connected to a reset supervisor  320  and to an Ethernet switch  322 . The Ethernet switch  322  communicates with a bank of status indicators in the form of LEDs  330 , configuration EEPROM  332 , a pair of fiber optic transceivers  334  and  336  as well as three 10/100 BaseT transceivers. Each of the 10/100 BaseT transceivers includes an RJ45 10/100 BaseT Ethernet jack  342 , an HV protection circuit  344  and a magnetic circuit  346  and is associated with a respective one of the transceivers  238 . The fiber optic transceivers  334  and  336  similarly are each coupled to a respective one of the fiber optic pairs  154  and  156 .  
         [0050]    The main processor  302  is also coupled to the mezzanine circuit board card connector  264  via a GCI  312 . When the mezzanine circuit board card connector  264  matingly engages with the mezzanine circuit board card connector  266  of the TEI subsystem  262 , the GCI  312  is connected to the GCI  384  of the TEI subsystem  262 .  
         [0051]    The TEI subsystem  262  includes a Codec  376  coupled to the GCI  384 . An RJ45 analog jack  370  is coupled to the Codec  376  via an HV protection circuit  378  and a data access arrangement (DAA)  400  to interface with the backend communications system. An RJ45 digital jack  374  is also connected to the mezzanine circuit board card connector  266  through an HV protection circuit  386  and custom interface circuits  388  and  390 . The jack  370  receives incoming copper analog POTs lines (not shown) and the jack  374  connects to a line leading to a digital telephone switch.  
         [0052]    Turning now to FIGS. 6 a  and  6   b , a wallbox  140  housing one of the front-end interfaces  126  is better illustrated. As can be seen the wallbox  140  includes a generally rectangular masonry housing  500  having a front face panel  502  through which conventional 110 volt power supply sockets  504  are exposed. An array  506  of jacks including two rows of jacks is also exposed. The jacks in the bottom row of the array  506  include the RJ45 10/100 BaseT Ethernet jacks  242 . The jacks in the top row of the array  506  include the RJ45 analog telephone jack  170  and the RJ45 digital telephone jack  174 .  
         [0053]    During powerup of the signal conversion system, the operating systems of the CPUs  200  and  300  in the backend and front-end interfaces  122  and  126  respectively go through initialization. During this initialization process, the backend and front-end interfaces  122  and  126  establish a communications relationship using an appropriate communications protocol. In the present embodiment, the backend and front-end interfaces  122  and  126  communicate using Internet Protocol (IP). Accordingly during initialization, IP addresses assigned to the backend and front-end interfaces  122  and  126  are exchanged by the CPUs  200  and  300  over the fiber optic link  146  and a client server relationship between the backend and front-end interfaces  122  and  126  is negotiated to establish an IP link therebetween. Daemons are used by the Linux operating system running on the CPUs  200  and  300  to control and maintain communications between the backend and front-end interfaces  122  and  126 . The Linux operating system separates communications into two tasks, namely a transmit task and a receive task. Transmit tasks are carried out over the transmit (Tx) fibers of the fiber optic pairs  154  and  156 . Receive tasks are carried out over the receive (Rx) fibers of the fiber optic pairs  154  and  156 . Each fiber defines a single direction combined voice and data channel.  
         [0054]    When the signal conversion system is in an idle state, regular IP traffic passes between the backend and front-end interfaces  122  and  126  over the fiber optic pairs  154  and  156  in a conventional manner allowing computer workstations  138  plugged into the jacks  242  to communicate with a backend communications system.  
         [0055]    When a telephone  134  or facsimile machine  136  that is connected to a jack  170  goes off hook, the off-hook condition is detected by the SLIC  180  and the CPU  200  is notified of the off-hook condition. The CPU  200  in turn opens an IP link with the backend interface  122  that was established during initialization. Quality of service is then invoked on the Ethernet switch  222  as required to tag Ethernet packets. As the outgoing number is dialled, the dialled number is managed by the SLIC  180  and sent to the CPU  200 . The CPU  200  in turn conveys the dialling sequence to the Ethernet switch  222 . The Ethernet switch  222  in turn routes the dialling sequence to the appropriate fiber optic transceiver  234 ,  236  which converts the dialling signals from electrical to optical form and transmits the signals over the transmit fiber of the selected fiber optic pair  154 ,  156  via the established IP link.  
         [0056]    When the backend interface  122  receives the optical signals, the received optical signals are converted back into electrical signals by the fiber optic transceiver  334 ,  336  before being conveyed to the Ethernet switch  322 . From the Ethernet switch  322 , the dialling sequence is conveyed to the CPU  300 . The CPU  300  in turn opens an outgoing line connection to the backend communications system via the Codec  376 , DAA  400  and HV protection circuit  378  and then transmits the dialling sequence to the backend communications system. Ringing signals and progress tones received by the backend interface  122  from the backend communications system are returned back to the SLIC  180  in a similar manner.  
         [0057]    When the call is answered and a communication connection with the called party has been established, voice and/or data signals are sent back and forth between the backend and frond end interfaces  122  and  126  over the transmit and receive fibers of the selected fiber optic pair  154 ,  156  via the established IP link for the remainder of the call. When an onhook state of the telephone  134  or facsimile machine  136  is detected by the SLIC  180 , the call is terminated and the backend and front-end interfaces  122  and  126  return to the idle state.  
         [0058]    When an incoming call directed to one of the telephones  134  or facsimile machines  136  is received from the backend communications system, the incoming ringing signals are detected by the DAA  400 . The DAA  400  in turn notifies the CPU  300 , which in turn opens a previously established IP link with the front-end interface  126 . Similarly, quality of service is invoked on the Ethernet switch  322  as required. The CPU  300  conveys the ringing signals to the Ethernet switch  322 . The Ethernet switch  322  in turn routes the ringing signals to the appropriate fiber optic transceiver  334 ,  336  which converts the signals from electrical to optical form and transmits the signals over the transmit fiber of the selected fiber optic pair  154 ,  156  via the established IP link.  
         [0059]    When the front-end interface  126  receives the optical signals, the received optical signals are converted back into electrical signals by the fiber optic transceiver  234 ,  236  before being conveyed to the Ethernet switch  222 . From the Ethernet switch  222 , the ringing signals are conveyed to the CPU  200 . The CPU  200  in turn conveys the ringing signals to the jack  170  via the Codec  176 , SLIC  180  and HV protection circuit  178  causing the communications device connected to the jack to ring. Call status/progress signalling and ringing/progress tones are sent back to the backend interface  122  over the IP link in the same manner.  
         [0060]    When the call is answered and a communication connection with the calling party has been established, voice and/or data signals are sent back and forth over the transmit and receive fibers of the selected fiber optic pair  154 ,  156  via the IP link for the remainder of the call. When the call is terminated and the telephone  134  or facsimile machine  136  returns to an on-hook condition, the on-hook condition is detected by the SLIC  180 . The SLIC  180  in turn notifies the CPU  200 , which in turn signals the CPU  300  allowing the backend and front-end interfaces  122  and  126  to return to the idle state.  
         [0061]    Incoming and outgoing communications using a digital telephone plugged into jack  174  are carried out in a manner similar to that described above.  
         [0062]    As will be appreciated, the signal conversion system allows communications devices configured for electrical signal communications, to communicate with a backend communications system over a fiber optic link through modular interfaces. When the need arrives to switch the premise wiring fully to optical, only the interfaces need be replaced due to the fact that the underlying fiber optic link between the backend communications system and the communications devices is provided. Replacing the interfaces is an easy task due to their modular configuration. This will greatly help to reduce the future costs associated with the switch to fully fiber optics.  
         [0063]    Although the TDI subsystem  162  of the front-end interfaces  126  is described as including one RJ45 analog telephone jack  170  and one RJ45 digital jack  174 , those of skill in the art will appreciate that the TDI subsystem  162  may include more or fewer of each type of jack. Also, if desired additional circuitry can be provided in the TDI subsystems  162  to support enhanced telephony features.  
         [0064]    If desired, the TDI subsystems  162  may be provided with local wireless interfaces such as Bluetooth, 802.11, or IrDA to enable wireless devices to communicate with the backend communications system through the backend and front-end interfaces  122  and  126  in the same manner described above. Control ports can also be provided on the TDI subsystems  162  to permit heating, ventilation and security systems to be controlled through the signal conversion system.  
         [0065]    In the preferred embodiment, the Codec  176  is described as communicating with the CPU  200  over GCIs  184  and  212 . If desired, an interchip digital link (IDL) interface may be used instead of the GCIs.  
         [0066]    The fiber optic cable used as the link between the backend and front-end interfaces  122  and  126  respectively may either be single-mode or multi-mode fiber optic cable. Although single-mode fiber is more expensive, longer fiber optic length cable runs are possible.  
         [0067]    In the embodiment described above, the runs of fiber optic cable  132  are described as terminating at wallboxes  140 . If desired, one or more of the runs of the fiber optic cable  132  may terminate at a surface mount box into which communications devices are plugged as shown in FIGS. 7 a  to  7   d . As can be seen, the surface mount box includes a generally rectangular housing  600  having a front panel  602  accommodating an array  606  of jacks. The jacks in the array  606  include the RJ45 10/100 BaseT Ethernet jacks  242 . The rear panel  612  of the housing  600  accommodates another array  616  of jacks. The jacks in the array  616  include the RJ45 analog telephone jack  170  and the RJ45 digital telephone jack  174 . The bottom  620  of the housing  600  has an opening  622  therein to expose the fiber optic transceivers  234  and  236  allowing the surface mount box to be coupled to the fiber optic link  146 .  
         [0068]    Although preferred embodiments of the present invention have been described, those of skill in the art will appreciate that variations and modifications may be made without departing from the spirit and scope thereof as defined by the appended claims.