text: various embodiments are described within the context of fiber optic service (“ fios ”) technology ; however , these embodiments and others may be readily adapted to other data and / or signal transmission technologies , such as , digital subscriber line (“ dsl ”), cable television networks , and the like . fig1 depicts a high level diagram of a system according to one embodiment . specifically , the system 100 of fig1 comprises an access network 110 , a network interface device (“ nid ”) 120 , a premises gateway or residential gateway device (“ gd ”) 130 , one or more data devices 140 , and a battery back - up and power unit 150 . the access network 110 comprises any access network suitable for conveying data , television signals , and more generally , communication signals to the nid 120 . the physical layer of the access network 110 may be optical , electrical , hybrid fiber - coax , wireless , and the like . regardless of the access network topology , the nid 120 operates to receive , translate , and transmit data between the access network 110 and the gd 130 . that is , the nid 120 may be selected to process optical ( e . g ., fios ), dsl , cable , and / or other access network data types to communicate thereby with a local data type , such as ethernet , 802 . 11 , and the like . the nid 120 comprises a signal processing unit 122 and a power processing unit 124 . the signal processing unit 122 processes data passed between the access network 110 and gd 130 . in the case of optically transported data , the signal processing unit 122 comprises a standard electrical and optical transmission and reception circuitry adapted to receive and convert optical data signals to electrical data signals and vice versa . in general , the signal processing unit 122 operates to translate data and other signals between the format appropriate for the access network 110 and the format appropriate for the gd 130 . the power processing unit 124 provides power appropriate to the signal processing unit 122 . the power processing unit 124 receives power to be processed via a cabling between the nid 120 and the gd 130 . in one embodiment the cabling cable comprises an rg - 6 coaxial cable carrying one or more of quadrature amplitude modulation (“ qam ”) data , multimedia over coax alliance (“ moca ”) data , home phoneline networking alliance (“ hpna ”) data , analog tv signals , analog phone signals , and the like . in another embodiment , the power processing unit 124 receives power to be processed via power over ethernet connection between the nid 120 and the gd 130 . in the essence , a single data communication cable / ethernet connector is used to convey both power and signals from the gd 130 to the nid 120 , as well signals from the nid 120 to the gd 130 . this communications cable / data cable may be single or multi - strand electrical wire . in one embodiment , the nid 120 includes a power extraction unit 126 that extracts power signals from the cabling between the nid 120 and the gd 130 and provides the extracted power signal ( s ) to the power processing unit 124 . in yet another embodiment , the cabling includes separate wires for carrying data signals and power signals . as those skilled in the art will appreciate , standard filtering circuitry , buffering circuitry and other signal processing circuitry has been omitted from fig1 for clarity . such circuitry is adapted to ensure that optical and electrical data signals and electrical power signals are properly conveyed and / or transformed , and that effects of noise , jitter , and other unwanted signal components are minimized while desired signal components are enhanced . the gd 130 includes a signal processing unit 132 and a power processing unit 134 . the power processing unit 134 receives power from the battery back - up and power unit 150 and provides power to the signal processing unit 132 . the gd 130 is depicted as including the battery backup and power unit 150 . however , the battery backup and power unit 150 may , for example , be a separate unit collocated or within the reasonable distance of the gd 130 . the signal processing unit 132 operates in a standard manner to propagate data between the nid 120 and data devices 140 . the signal processing unit 132 processes signals received from the nid 120 and provides the processed signals in appropriate format to the data devices 140 , such as one or more television systems 140 1 , one or more computer systems 140 2 , one or more telephones 140 3 , and other data devices 140 4 , such as a security system . similarly , the data devices 140 may provide return data to the signal processing unit 132 for subsequent propagation to the access network 110 via the nid 120 . the power processing device 134 provides power to the signal processing unit 132 . in addition , the power processing device 134 provides an output signal p - out which is coupled to the cabling cable between the gd 130 and the nid 120 . in one embodiment , a power injection device 136 located within or outside of the gd 130 injects the output signal p - out into a signal path within the cabling between the gd 130 and the nid 120 . p - out preferentially comprises a relatively low voltage direct current ( dc ) signal ( e . g ., 12v or 24v ) which may be conveyed to the nid 120 along with other data signals . the p - out signal is extracted by the power extraction unit 126 and processed by power processor 124 to provide appropriate power to the nid 120 circuitry . alternatively , the p - out signal may be provided directly from the battery back - up and power unit 150 and merely passing through the gd 130 to the cabling cable . it should be noted that while in fig1 the power extraction unit 126 and power injection unit 136 are depicted as being part of the nid 120 and gd 130 respectively , both the power extraction unit 126 and the power injection unit 136 may be independent devices . also , they may be part of power processing units 124 and 134 or signal processing units 122 and 132 respectively . furthermore , more than one power extraction unit 126 or power injection unit 136 could be employed within the system 100 . it should be further noted that both power extraction unit 126 and power injection unit 136 may be omitted from the system 100 . for example , if separate wires are used to transmit signals and power , then a separate wire transmitting power could be used to connect the power processing units 124 directly to power processing unit 134 or to the battery back - up and power unit 150 . the battery back - up and power unit 150 provides the initial power used by the power processing unit 134 . the battery back - up and power unit 150 normally converts power from an ac source , such as a standard household electrical outlet , to a power signal p - in suitable for use by the power processing unit 134 . however , in the event of a power failure , battery power is processed by power conversion circuitry ( such as , voltage inverters , filters , an so on ( not shown )) to ensure that the power signal p - in is still generated by the battery back - up and power unit 150 . one embodiment operates to convey power to the external nid 120 using the same cabling as for signal propagation . in this matter , the power necessary to operate the nid 120 is always available , irrespective of the type of access network utilized . that is , if a non - electrical access network is used ( i . e ., an optical network ) where the power cannot be received from the access network 110 , the nid 120 is powered by the gd 130 . additionally , the output power signal p - out may be coupled to the cabling between the gd 130 and one or more data devices 140 ( e . g ., a telephone 140 3 ). such output signal p - out can be provided continuously and / or only in the case of the power failure . in this manner , the phone service is provided even when power is lost . the gd 130 optionally monitors the status of the battery back - up and power unit 150 . the battery back - up and power unit 150 includes in one embodiment a status processing unit 152 which monitors the status of a battery 154 , such as whether the battery 154 is hot , fully charged , weak , needs replacement , and so on . the status processing unit 152 detects a status of battery 154 and transmits an appropriate signal to the signal processing unit 132 . in one embodiment , the signal processing unit 132 processes the signal from the status processing unit 152 and provides the processed signal to the nid 120 for the subsequent transmission to the access network 110 . in another embodiment , the signal processing unit 132 processes the signal from the status processing unit 152 and provides the processed signal to one of the data devices 140 . in yet another embodiment , the signal processing unit 132 processes the signal from the status processing unit 152 and provides the processed signal to a battery indicator 138 , which is included in the gd 130 . in response , the battery indicator 138 displays the battery status corresponding to the processed signal . in fig1 the gd 130 and a battery back - up and power unit 150 are located internal to a customer &# 39 ; s premises ( inside ), while the network interface device is located external to the customer &# 39 ; s premises ( outside ). however , in another embodiment , the nid 120 is also located internal to the customer premises . further , the nid 120 and gd 130 may be collocated or combined into a single device . the above described embodiments may be implemented within the context of methods , computer readable media , and computer program processes . as such , it is contemplated that some of the steps discussed herein as methods , algorithms , and / or software processes may be implemented within hardware ( e . g ., circuitry that cooperates with a processor to perform various steps ), software or a combination of hardware and software . one embodiment may be implemented as a computer program product wherein computer instructions , when processed by a computer , adapt the operation of the computer such that the methods and / or techniques described herein are invoked or otherwise provided . instructions for invoking the methods may be stored in fixed or removable media , transmitted via a data stream in a signal bearing medium such as a broadcast medium , and / or stored within a working memory or mass storage device associated with a computing device operating according to the instructions . generally speaking , a computing device including a processor , memory , and input / output means may be used to process software instructions , store software instructions , and / or propagate software instructions to or from a communications channel , storage device , or other computer / system . it is noted that the various processing ( power and signal ) elements described herein may be implemented in this manner . although various embodiments have been shown and described in detail herein , those skilled in the art can readily devise many other varied embodiments that still incorporate the described teachings .