초록 ▼

A serial intelligent cell (SIC) and a connection topology for local area networks using Electrically-conducting media. A local area network can be configured from a plurality of SIC's interconnected so that all communications between two adjacent SIC's is both point-to-point and bidirectional. Each

A serial intelligent cell (SIC) and a connection topology for local area networks using Electrically-conducting media. A local area network can be configured from a plurality of SIC's interconnected so that all communications between two adjacent SIC's is both point-to-point and bidirectional. Each SIC can be connected to one or more other SIC's to allow redundant communication paths. Communications in different areas of a SIC network are independent of one another, so that, unlike current bus topology and star topology, there is no fundamental limit on the size or extent of a SIC network. Each SIC can optionally be connected to one or more data terminals, computers, telephones, sensors, actuators, etc., to facilitate interconnectivity among such devices. Networks according to the present invention can be configured for a variety of applications, including a local telephone system, remote computer bus extender, multiplexers, PABX/PBX functionality, security systems, and local broadcasting services. The network can use dedicated wiring, as well as existing wiring as the in-house telephone or electrical wiring.

대표청구항 ▼

What is claimed is: 1. A local area network in a building for carrying power and digital data, said network comprising: a first node including a first data port for coupling to a first data unit, a second node including a second data port for coupling to a second data unit and a third node includin

What is claimed is: 1. A local area network in a building for carrying power and digital data, said network comprising: a first node including a first data port for coupling to a first data unit, a second node including a second data port for coupling to a second data unit and a third node including a third data port for coupling to a third data unit; a first wiring segment having two ends and comprising at least one first twisted wire pair at least in part in walls of a building, wherein each end of said first wiring segment is terminated in a respective first terminating connector, at least one of the first terminating connectors is part of an outlet, said first wiring segment connects only said first and second nodes in a point-to-point connection for a first full-duplex data communication of serial digital data over said first wiring segment between the first and second nodes, and said first wiring segment concurrently carries a first DC power signal substantially without interfering with the first communication of serial digital data; and a second wiring segment having two ends and comprising at least one second twisted wire pair at least in part in walls of a building, wherein each end of said second wiring segment is terminated in a respective second terminating connector, at least one of the second terminating connectors is part of an outlet, said second wiring segment connects only said first and third nodes in a point-to-point connection for a second full-duplex communication of serial digital data over said second wiring segment between the first and third nodes, and said second wiring segment concurrently carries a second DC power signal substantially without interfering with the second communication of serial digital data; wherein: said network is operative to effect the second communication independently from the first communication, said first node is connectable to a power source to be powered from the power source, and the first and second DC power signals are provided by the power source, said second node is at least in part powered by the first DC power signal, said third node is at least in part powered by the second DC power signal, each node is operative to couple serial digital data to a connected data unit via a respective data port for coupling to the connected data unit digital data carried over said first or second wiring segment, and the first and second DC power signals are current limited. 2. The network according to claim 1, wherein the first and second full-duplex communications of serial digital data are packet-based communications and said network comprises first and second fuses for respectively effecting the current limiting of the first and second DC signals. 3. The network according to claim 1 wherein each of said nodes is addressable. 4. The network according to claim 3, wherein at least one of said nodes has a manually assigned address. 5. The network according to claim 3, wherein at least one of said nodes has an automatically assigned address. 6. The network according to claim 3, wherein at least one of said nodes has an address assigned by a data unit coupled to said at least one of said nodes. 7. The network according to claim 1, wherein at least one of said nodes is either pluggable into an outlet or attachable to an outlet. 8. The network according to claim 1 configured to function as a multiplexer, wherein said first data port of said first node is coupled to the first data unit to conduct a serial digital data stream containing time multiplexed first and second data streams, the first data stream is routed via said network and coupled only to said data port of said second node for coupling to the second data unit, and the second data stream is routed via the network and coupled only to said data port of said third node for coupling to the said third data unit. 9. The network according to claim 8 configured to function as a voice multiplexer, wherein the first and said second data streams are digitized telephony signals. 10. The network according to claim 9, wherein the serial digital data stream is a PCM highway. 11. The network according to claim 1, further comprising a third wiring segment connecting said second and third nodes to impart a ring topology to said network. 12. The network according to claim 11, further operative to reroute a digital data in the event of failure of one of said wiring segments. 13. The network according to claim 1, wherein at least one of said nodes further comprises: a telephone connector connectable to a telephone set; and a converter for converting between analog telephony and digitized telephony coupled between said data port of said at least one of said nodes and said telephone connector. 14. The network according to claim 13 configured to function as an intercom, wherein two of said nodes are connectable to respective telephone sets, and said network is operative to allow said two telephone sets to communicate with each other. 15. The network according to claim 1 further operative for coupling to a computer plug-in device, wherein at least one of said nodes further comprises a standard computer bus slot coupled to said data port of said at least one of said nodes. 16. The network according to claim 1, wherein at least one of said data ports is Ethernet based. 17. The network according to claim 1, wherein at least one of said nodes is housed within a single enclosure structured to at least in part replace an existing standard outlet. 18. The network according to claim 1, wherein at least one of said nodes is attachable to a wall of a building or is at least in part housed within an outlet. 19. The network according to claim 1 further operative to power an apparatus, wherein said second node further comprises a power connector connectable to the apparatus for coupling the first DC power signal to the apparatus. 20. The network according to claim 19, wherein information carried by a data signal in said network is used to control or monitor the powering of the apparatus. 21. The network according to claim 20, wherein the control is one of: an on/off operation; timing of operations; and a delayed start. 22. The network according to claim 20, wherein the monitoring is power consumption metering. 23. The network according to claim 1, wherein at least one of the wiring segments carries digitized video or digitized voice data. 24. The network according to claim 1, wherein at least one of said wiring segments comprises dedicated DC power conductors carrying the respective DC power signal and data conductors carrying distinct from the DC power conductors and carrying the respective serial digital data. 25. The network according to claim 1, wherein at least one of said wiring segments carries the respective DC power signal and data over the same conductors. 26. The network according to claim 25, wherein the respective DC power signal and data are carried over distinct frequency bands. 27. The network according to claim 1, wherein the network is further operative to accommodate line reversal and provide power protection. 28. The network according to claim 27, wherein the line reversal function uses a diode-based bridge. 29. The network according to claim 1 further operative to function as a repeater, wherein said second and third nodes communicate with each other while said first node repeats data between said first and second wiring segments. 30. The network according to claim 1 further operative as a control network, wherein a first one of said nodes is connectable to a sensor and a second one of said nodes is connectable to an actuator, and wherein operation of the actuator is dependent upon the sensor output. 31. The network according to claim 1 further operative for remote metering, and further comprising a power meter for measuring the first DC power signal. 32. The network according to claim 31 wherein a representation of the measured value of said first DC signal is carried in one of the serial digital data. 33. The network according to claim 1 wherein at least one of said nodes is housed with a connected data unit. 34. A device for coupling power and digital data in a local area network, for use with first and second point-to-point local area network wiring segments each comprising at least one twisted-wire pair and carrying DC power and full-duplex serial digital data signals, said device comprising: a first connector for connecting to said first wiring segment, for coupling a first DC power signal and first full-duplex serial digital data to said first wiring segment; a first transceiver coupled to said first connector for communication of the first full duplex serial digital data with a transceiver of the same type as said first transceiver over said first wiring segment; a second connector for connecting to said second wiring segment for coupling a second DC power signal and second full-duplex serial digital data to said second wiring segment; a second transceiver coupled to said second connector for communication of the second full-duplex serial digital data with a transceiver of the same type as said second transceiver over said second wiring segment; a third transceiver coupled to said first and second transceivers for full-duplex digital data communication with a data unit, a data connector coupled to said third transceiver for connecting to the data unit for coupling between the first and second full-duplex serial digital data and the data unit; a power connector for coupling to a power source that supplies the first and second DC power signals; and first and second current limiting circuits respectively coupled between said power connector and the first and second connectors for respectively current limiting of the first and second DC power signals, wherein the first and second full-duplex serial digital data are independent and distinct from each other. 35. The device according to claim 34, wherein the full-duplex communication of serial digital data is packet-based communication, and said device is addressable. 36. The device according to claim 35, wherein said device has a manually assigned address. 37. The device according to claim 35, wherein said device has an automatically assigned address. 38. The device according to claim 35, wherein said device has an address assigned by the data unit or a further data unit coupled to said device. 39. The device according to claim 34 further functioning as a multiplexer, wherein the communication with the data unit includes communication of a serial digital data stream carrying time multiplexed first and second data streams, and wherein the first data stream is coupled only to said first transceiver, and the second data stream is coupled only to said second transceiver. 40. The device according to claim 39 functioning as a voice multiplexer, wherein the first and said second data streams are digitized telephony signals. 41. The device according to claim 40, wherein the serial digital data stream is a PCM highway. 42. The device according to claim 34 further operative for coupling to a computer plug-in member, wherein said device further comprises a standard computer bus slot coupled to said first transceiver. 43. The device according to claim 34, wherein the third transceiver and said data connector form an interface to the data unit which conforms to an Ethernet standard. 44. The device according to claim 34, further housed within a single enclosure, structured to at least in part replace an existing outlet or to be pluggable into an outlet. 45. The device according to claim 34, wherein at least one of the wiring segments carries digitized video data or digitized voice data. 46. The device according to claim 34, wherein at least one of the wiring segments carries the respective DC power signal over dedicated conductors distinct from the at least one twisted pair carrying the respective serial digital data. 47. The device according to claim 34, wherein at least one of the wiring segments carries the respective power signal and serial digital data over the same conductors, and said device further comprises a power/data combiner/splitter coupled to said first connector for combining and separating the DC power signal and serial digital data. 48. The device according to claim 47, wherein said power/data combiner/splitter is based on passive components. 49. The device according to claim 48, wherein said power/data combiner/splitter is based on a center-tapped transformer or a set including a high pass filter and a low pass filter, wherein said high pass filter passes only the serial digital data and said low pass filter pass only the DC power signal. 50. The device according to claim 34 further operative to function as a repeater, wherein said first and second transceivers are coupled to each other to transparently pass data between said first and second connectors. 51. The device according to claim 34 wherein first and second current limiting circuits are each based on a respective fuse. 52. The device according to claim 34 further operative for remote metering and further comprising a power meter for measuring or sensing the first DC power signal. 53. The device according to claim 52 wherein data representing the measured value of the first DC power signal is carried as part of one of the first and second serial digital data. 54. The device according to claim 34 wherein said device is housed with the data unit. 55. The device according to claim 34 in combination with first and second point-to-point local area network wiring segments. 56. A local area network in a building for wired coupling of a plurality of nodes, the network comprising: first, second, third and fourth nodes; and first, second and third point-to-point wiring segments, each wiring segment comprising at least two conductors, wherein: said first wiring segment is connected only between said first and second nodes for carrying out half-duplex or full-duplex point-to-point digital data communication of first serial digital data and for simultaneously carrying a first power signal, said first node couples the first power signal to said first wiring segment, and said second node is operative to be at least in part powered by the first power signal, said second wiring segment is connected only between said second and third nodes for carrying out half-duplex or full-duplex point-to-point digital data communication of second serial digital data and for simultaneously carrying a second power signal, said second node couples the second power signal to said second wiring segment, and said third node is operative to be at least in part powered by the second power signal, said third wiring segment is connected only between said second and fourth nodes for carrying out half-duplex or full-duplex point-to-point digital data communication of third serial digital data and for simultaneously carrying a third power signal, said second node couples the third power signal to said third wiring segment, and said fourth node is operative to be at least in part powered by the third power signal, and said second node is operative for passing therethrough: at least part of the first serial digital data and the second serial digital data; at least part of the first serial digital data and the third serial digital data, and at least part of the power from the first power signal to the second and third power signals. 57. The network according to claim 56, wherein at least one of said wiring segments comprises one of: a twisted-wire pair; a coaxial cable; telephone wiring; and powerline wiring. 58. The network according to claim 56, wherein at least one of said nodes is addressable in the network. 59. The network according to claim 58, wherein said at least one node has a manually assigned address. 60. The network according to claim 58, wherein said at least one node has an automatically assigned address. 61. The network according to claim 58, wherein said at least one node has an address assigned by a data unit connected to the node. 62. The network according to claim 56, wherein the first, second and third serial digital data are packet-based. 63. The network according to claim 56, wherein at least one of said nodes is wall mounted and at least one of said wiring segments is inside a wall. 64. The network according to claim 56, wherein at least one of said nodes is housed within an outlet. 65. The network according to claim 56, wherein the first, second and third power signals are direct current (DC) power signals. 66. The network according to claim 56, wherein at least one of said third and fourth nodes is operative to power a device connected thereto. 67. The network according to claim 66, further operative for connecting and disconnecting power from a connected device in response to a data element of serial digital data carried over one of said wiring segments connected to said one of said third and fourth nodes. 68. The network according to claim 66, further operative for measuring the power supplied to the connected device and transmitting data representing the measured power as part of the serial digital data carried over a wiring segment connected to said one of said third and fourth nodes. 69. The network according to claim 56, wherein one of said nodes is connectable to a sensor, a distinct other one of said nodes is connectable to an actuator, and the actuator operates in response to the sensor output. 70. The network according to claim 56, wherein at least one of said wiring segments is at least in part in a wall of a house and is connected to a respective one of said nodes via at least one outlet. 71. The network according to claim 56, wherein all of said wiring segments carries the respective power signals over dedicated conductors. 72. The network according to claim 56, wherein at least one of said wiring segments carries a respective power signal and digital data over the same wires. 73. The network according to claim 72, wherein said at least one of said wiring segments carries the respective power signal and digital data using frequency division multiplexing, wherein the power signal is carried over a frequency band distinct from the frequency band carrying the digital data. 74. The network according to claim 56, wherein at least one of said wiring segments comprises a twisted-wire pair, and the power signal is a DC power signal. 75. The network according to claim 56, wherein at least one of said wiring segments is AC power wiring, and the power signal is an AC power signal. 76. The network according to claim 56, wherein at least one of said nodes further comprises a visual indicator for indicating a communication status. 77. The network according to claim 56, wherein the same protocol is used for the data carried over said first, second and third wiring segments. 78. The network according to claim 56, wherein information carried by at least one out of the first, second and third serial digital data is used to control at least one of the first, second and third power signals. 79. The network according to claim 78, wherein the control is one of: on/off operation; timing of operations; and delayed start. 80. The network according to claim 78, wherein at least one of the first, second and third serial digital data signals is used to monitor or sense the power consumption from at least one out of said first, second and third power signals. 81. The network according to claim 56, wherein at least one of the first, second and third power signals is current limited. 82. A device for configuring a network for communication and power coupling communication data and power between a first wiring segment and second and third wiring segments, for use with first, second and third point-to-point wiring segments in a building each having two ends, each wiring segment having at least two conductors and simultaneously carrying serial digital data and power signals, said device comprising: a first connector for connecting to one end of the first wiring segment that simultaneously carries a first serial bi-directional digital data signal and a first power signal; a first transceiver coupled to said first connector for conducting point to point communication over the first wiring segment with a mating transceiver connected to the other end; a second connector for connecting to the second wiring segment that simultaneously carries a second serial bi-directional digital data signal and a second power signal; a second transceiver coupled to said second connector for conducting point to point communication over the second wiring segment, wherein said second transceiver is coupled to said first transceiver for passing at least part of the first data between said first and second transceivers, and said second connector is coupled to said first connector for forming the second power signal from power contained in the first power signal; a third connector for connecting to the third wiring segment that simultaneously carries a third serial bi-directional digital data signal and a third power signal; a third transceiver coupled to said third connector for conducting point to point communication over the third wiring segment, wherein said third transceiver is coupled to said first transceiver for passing at least part of the first data between said first and third transceivers, wherein said third connector is coupled to said first connector for forming the third power signal from power contained in the first power signal; and a single enclosure housing said first, second and third connectors and said first, second and third transceivers. 83. The device according to claim 82, wherein said first, second and third transceivers are operative for full duplex, packet-based communication over respectively connected wiring segments. 84. The device according to claim 82, wherein at least one of the wiring segments comprises one of: a twisted-wire pair; a coaxial cable; telephone wiring; and powerline wiring, and one of said transceivers connected to the at least one wiring segment is operative to conduct digital data over the at least one wiring segment. 85. The device according to claim 82, wherein said device is addressable in the network. 86. The device according to claim 85, wherein said device has a manually assigned address. 87. The device according to claim 85, wherein said device has an automatically assigned address. 88. The device according to claim 85, wherein said device has an address that is assigned by a data unit connected to said device. 89. The device according to claim 82, wherein said device is wall mounted and at least one of the wiring segments is inside a wall in a building. 90. The device according to claim 82, wherein said device is housed within an outlet. 91. The device according to claim 82, wherein the power signals carried in all of the wiring segments are DC power signals. 92. The device according to claim 82, wherein at least one of the wiring segments is at least in part in a wall of a building, and said device is constructed to be connectable to an outlet. 93. The device according to claim 82, wherein at least one of the wiring segments carries the respective power signal over dedicated conductors. 94. The device according to claim 82, wherein at least one of the wiring segments carries the respective digital data and power signals over the same wires. 95. The device according to claim 94, wherein the at least one wiring segment carries the respective digital data and power signals using frequency division multiplexing, wherein the power signal is carried over a frequency band distinct from the frequency band carrying the digital data signal. 96. The device according to claim 82, wherein at least one of the wiring segments is a twisted-wire pair, and the power signal carried by the at least one wiring segment is a DC power signal. 97. The device according to claim 82, wherein at least one of said wiring segment is AC power wiring, and said power signal is a AC power signal. 98. The device according to claim 82, further comprising a visual indicator for indicating a communication status. 99. The device according to claim 82, wherein all of the digital data signals are formatted according to the same protocol. 100. The device according to claim 82 further being wall-mountable. 101. The device according to claim 82 further comprising: a data/power splitter for separating data and power signals carried over the same conductors and having first, second and third ports, said data/power splitter being operative to bi-directionally pass a digital data signal between said first and second ports, and to pass a DC power signal from said first port to said third port, wherein said first port of said data/power splitter is coupled to said first connector, said second port of said data/power splitter is coupled to said first transceiver, and said third port of said data/power splitter is coupled to said second and third connectors. 102. The device according to claim 101 wherein said data/power splitter comprises a center-tapped transformer. 103. The device according to claim 101 wherein said data/power splitter comprises a low pass filter coupled between said first and third ports, and a high pass filter coupled between said first and second ports. 104. The device according to claim 82 further comprising: a data/power combiner for combining data and power signals to be carried over the same conductors and having first, second and third ports, said data/power combiner being operative to bi-directionally pass a digital data signal between said first and second ports, and to pass a DC power signal from said third port to said first port, wherein said first port of said data/power splitter is coupled to said second connector, said second port of said data/power splitter is coupled to said second transceiver, and said third port of said data/power splitter is coupled to said first connector. 105. The device according to claim 104 wherein said data/power splitter comprises a center-tapped transformer. 106. The device according to claim 104 wherein said data/power splitter comprises a low pass filter coupled between said first and third ports, and a high pass filter coupled between said first and second ports. 107. The device according to claim 82, wherein information carried in at least one out of the first, second and third serial digital data signals is used to control at least one of the first, second and third power signals. 108. The device according to claim 107, wherein the control is one of: an on/off operation, timing of operations; and delayed start. 109. The device according to claim 107, wherein the at least one of the data signals is used to monitor the power consumption of at least one of second and third power signals. 110. The device according to claim 82 further comprising a current limiter for limiting the current of at least one of the first, second and third power signals. 111. A device for coupling to a DC power signal and a packet-based full-duplex serial digital data signal simultaneously carried over an Ethernet-based local area network (LAN) wiring comprising at least one twisted-wire pair, said device comprising: a LAN wiring connector for connecting to the wiring; a power/data splitter having first, second and third ports, wherein only the DC power signal is passed from said first port to said second port, and only the digital data signal is passed between said first and third ports, and wherein said power/data splitter comprises at least one center tap transformer, and wherein said first port is coupled to said LAN wiring connector; a LAN transceiver coupled to said third port of said power/data splitter for point-to-point communication of the packet-based full duplex serial digital data with a transceiver of the same type as said LAN transceiver over said LAN wiring; a power supply for DC voltage converting coupled to and powered from said second port of said power/data splitter, said power supply having a power source port; a diode bridge coupled between said LAN wiring connector and said power supply for ensuring proper voltage polarity feeding to said power supply in case of wires swapping, wherein said LAN transceiver is connected to said power source port for being powered from said power supply; a data port coupled to said LAN transceiver and connectable to a data unit for coupling the packet-based full-duplex serial digital data signal to the data unit; and a visual indicator powered by said power supply for indicating the device status, wherein the device is addressable in the LAN. 112. The device according to claim 111, wherein said device has a manually assigned address. 113. The device according to claim 111, wherein said device has an automatically assigned address. 114. The device according to claim 111, wherein said device has an address assigned by the data unit. 115. The device according to claim 111 further operative for coupling to a computer plug-in device, wherein said device further comprises a standard computer bus slot coupled to said data port and coupled to power the computer plug-in device from said power supply. 116. The device according to claim 111 in combination with a single enclosure housing said device, said single enclosure being structured to at least in part substitute for an existing outlet or to be pluggable into an outlet. 117. The device according to claim 111, wherein said power/data splitter consists of only passive components. 118. The device according to claim 111 wherein: the data unit is a wired digital data unit; said data port comprises a digital data connector connectable to the wired digital data unit; and said device further comprises a further transceiver coupled between said LAN transceiver and said digital data connector for bi-directional digital data communication with said wired digital data unit. 119. The device according to claim 118 wherein the communication with said wired digital data unit is full duplex and based on a standard parallel interface. 120. The device according to claim 118 wherein the communication with said wired digital data unit is full duplex standard serial communication. 121. The device according to claim 120, wherein said data unit has an Ethernet based interface. 122. The device according to claim 111 further comprising firmware and a processor executing said firmware, and wherein said processor is coupled to said LAN transceiver for controlling said LAN transceiver. 123. The device according to claim 111 further operative to power the data unit, wherein said data port is coupled to said power supply for powering the connected data unit therefrom. 124. The device according to claim 111 further operative for sensing a physical phenomenon, wherein said data unit is an analog sensor for sensing a physical phenomenon, and wherein said device further comprises an analog to digital converter coupled between said data port and said LAN transceiver for converting analog signals to digital signals. 125. The device according to claims 124, wherein the digital data signal contains digitized audio or video data, and said sensor is an audio or video device. 126. The device according to claim 111 further operative for producing a physical phenomenon, wherein said data unit is an analog actuator for producing the physical phenomenon, and wherein said device further comprises a digital to analog converter coupled between said data port and said LAN transceiver for converting digital signals to analog signals. 127. The device according to claims 126, wherein the digital data signal contains digitized audio or video data, and said actuator is an audio or video device. 128. The device according to claim 111 further operative for telephony use wherein: the packet-based full-duplex serial digital data comprises digitized telephony data; the data unit is a telephony apparatus said device further comprises connected to constitute a termination of a telephone link; and a converter coupled between said LAN transceiver and said data port for coupling the digitized telephony data to the telephony apparatus. 129. The device according to claim 128 wherein the telephony apparatus is an analog telephone set, and wherein said data port comprises a standard analog telephone connector. 130. The device according to claim 128 in combination with an enclosure enclosing said device and the telephony apparatus enclosure. 131. The device according to claim 111 further enclosed with the data unit coupled to said device. 132. A device for coupling to a cable that simultaneously carries a DC power signal over two dedicated conductors and a half-duplex serial digital data signal over at least one twisted-wire pair, said device comprising: a wiring connector for connecting to the cable; a transceiver coupled to said wiring connector for being powered from the DC power signal and for point-to-point communication of the half duplex serial digital data with a transceiver of the same type as said LAN transceiver over said cable; a data port coupled to said transceiver and couplable to a data unit for coupling the half-duplex serial digital data signal to the data unit; and a visual indicator coupled to said wiring connector to be powered by the power signal for indicating a status of said device, wherein: said device is addressable; the data unit is a wired digital data unit; said data port comprises a digital data connector connectable to the wired digital data unit; and said device further comprises a further second transceiver coupled between said transceiver and said digital data connector for bi-directional digital data communication with said wired digital data unit. 133. The device according to claim 132, wherein said device has a manually assigned address. 134. The device according to claim 132, wherein said device has an automatically assigned address. 135. The device according to claim 132, wherein said device has an address assigned by said data unit. 136. The device according to claim 132 further operative for coupling to a computer plug-in device, wherein said device further comprises a standard computer bus slot coupled to said data port and coupled to power the computer plug-in device from said DC power signal. 137. The device according to claim 132 in combination with a single enclosure housing said device, said single enclosure being structured to at least in part substitute for an existing outlet or to be pluggable into an outlet. 138. The device according to claim 132 wherein the communication with said wired digital data unit is full duplex and based on a standard parallel interface. 139. The device according to claim 132 wherein the communication with said wired digital data unit is full duplex standard serial communication. 140. The device according to claim 139, wherein said data unit has an Ethernet based interface. 141. The device according to claim 132 further operative to power the data unit, wherein said data port is coupled to said power supply for powering the connected data unit therefrom. 142. A device for coupling to a cable that simultaneously carries a DC power signal over two dedicated conductors and a half-duplex serial digital data signal over at least one twisted-wire pair, said device comprising: a wiring connector for connecting to the cable; a transceiver coupled to said wiring connector for being powered from the DC power signal and for point-to-point communication of the half duplex serial digital data with a transceiver of same type as said LAN transceiver over said cable; a data port coupled to said transceiver and couplable to a data unit for coupling the half-duplex serial digital data signal to the data unit; and a visual indicator coupled to said wiring connector to be powered by the power signal for indicating a status of said device, wherein: said device is addressable; and said device further comprises firmware and a processor executing said firmware, and wherein said processor is coupled to said transceiver for controlling said transceiver. 143. A device for coupling to a cable that simultaneously carries a DC power signal over two dedicated conductors and a half-duplex serial digital data signal over at least one twisted-wire pair, said device comprising: a wiring connector for connecting to the cable; a transceiver coupled to said wiring connector for being powered from the DC power signal and for point-to-point communication of the half duplex serial digital data with a transceiver of the same type as said LAN transceiver over said cable; a data port coupled to said transceiver and couplable to a data unit for coupling the half-duplex serial digital data signal to the data unit; and a visual indicator coupled to said wiring connector to be powered by the power signal for indicating a status of said device, wherein: said device is addressable; said device is further operative for sensing a physical phenomenon; said data unit is an analog sensor for sensing a physical phenomenon; and said device further comprises an analog to digital converter coupled between said data port and said transceiver for converting analog signals to digital signals. 144. The device according to claims 143, wherein the digital data signal contains digitized audio or video data, and said sensor is an audio or video device. 145. A device for coupling to a cable that simultaneously carries a DC power signal over two dedicated conductors and a half-duplex serial digital data signal over at least one twisted-wire pair, said device comprising: a wiring connector for connecting to the cable; a transceiver coupled to said wiring connector for being powered from the DC power signal and for point-to-point communication of the half duplex serial digital data with a transceiver of the same type as said LAN transceiver over said cable; a data port coupled to said transceiver and couplable to a data unit for coupling the half-duplex serial digital data signal to the data unit; and a visual indicator coupled to said wiring connector to be powered by the power signal for indicating a status of said device, wherein: said device is addressable; said device is further operative for producing a physical phenomenon; said data unit is an analog actuator for producing the physical phenomenon; and said device further comprises a digital to analog converter coupled between said data port and said transceiver for converting digital signals to analog signals. 146. The device according to claims 145, wherein the digital data signal contains digitized audio or video data, and said actuator is an audio or video device. 147. A device for coupling to a cable that simultaneously carries a DC power signal over two dedicated conductors and a half-duplex serial digital data signal over at least one twisted-wire pair, said device comprising: a wiring connector for connecting to the cable; a transceiver coupled to said wiring connector for being powered from the DC power signal and for point-to-point communication of the half duplex serial digital data with a transceiver of the same type as said LAN transceiver over said cable; a data port coupled to said transceiver and couplable to a data unit for coupling the half-duplex serial digital data signal to the data unit; and a visual indicator coupled to said wiring connector to be powered by the power signal for indicating a status of said device, wherein: said device is addressable; said device is further operative for telephony use; the packet-based full-duplex serial digital data signal comprises digitized telephony data; the data unit is a telephony apparatus connected to constitute a termination of a telephone link; and said device further comprises a converter coupled between said transceiver and said data port for coupling the digitized telephony data to the telephony apparatus. 148. The device according to claim 147 wherein the telephony apparatus is an analog telephone set, and wherein said data port comprises a standard analog telephone connector. 149. The device according to claim 147 in combination with an enclosure enclosing said device and the telephony apparatus.