(12) United States Patent
`Katzenberg et al.
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 6,218,930 B1
`Apr. 17, 2001
`
`USU06218930B1
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`.
`9/1992 Jenneve et al.
`5,144,544
`2/1994 Ziermann ...................... .. 363/21
`5,289,359 “
`4/1995 Cummings ct al.
`340/568
`5,406,260 ’*
`5,461,671 * 10/1995 Sakuragi et al.
`379/400
`5,483,574 *
`1/1996 Yuyama
`.. 379/32
`5,608,792 ’*
`3/1997 Laidlcr ............ ..
`.. 379/386
`
`
`
`* cited by examiner
`
`Primary Examiner—Jcl1ery A. Holsass
`Assistant Exzzminer—Tai T. Nguyen
`(74) Attorney, Agent, or Firm—William C. Crutcher
`
`(5 7)
`
`ABSTRACT
`
`Apparatus for remotely powering access equipment over a
`10/100 switched Ethernet network comprises an Ethernet
`switch card with a phantom power supply for remote access
`equipment and added circuitry for automatic detection of
`remote equipment being connected to the network; deter-
`mining whether the remote equipment is capable of accept-
`ing remote power in a non-intrusive manner, delivering the
`phantom power to the remote equipment over the same wire
`pairs that deliver the data signals, and automatically detect-
`ing if the remote equipment is removed from the network.
`
`9 Claims, 3 Drawing Sheets
`
`(54) APPARATUS AND METHOD FOR
`REMOTELY POVVERING ACCESS
`EQUIPMENT OVER A 10/100 SWITCHED
`ETHERNET NETVVORK
`
`(75)
`
`Inventors: Boris Katzenherg, Trumbull; Joseph
`A. Dcptula, Watertown, both of CT
`(US)
`
`(73) Assignee: Merlot Communications, Bethel, CT
`(US)
`
`*
`
`Notice:
`
`J
`.
`Sub'ect to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 09/520,350
`
`(22)
`
`Filed:
`
`Mar. 7, 2000
`
`(60)
`
`Related U.S. Application Data
`Provisional application No. 60/123,688, filed on Mar. 10,
`1999.
`
`Int. (11.7 ................................................... M04M 11/04
`(51)
`(52) U.S. Cl.
`.............................. .. 340/310.01; 340/310.02;
`340/310.06; 340/310.07; 379/386; 379/400;
`379/32
`(58) Field of Search ......................... 340/310.01, 310.07,
`340/825.16, 310.02, 310.06; 379/386, 400,
`32
`
`10
`
`
`
`
`Remote Access
`Equipment
`
`
`Network Data
`
`20
`
`16
`
`ower Source
`
`}8
`
`¥J
`
`
`
`
`
`
`
`§\ 26
`
`To Network
`
`A/D Converter
`and
`Microprocessor
`
`
`
`24/
`
`Aerohive - Exhibit 1037
`
`Aerohive - Exhibit 1037
`
`

`
`U.S. Patent
`
`Apr. 17, 2001
`
`Sheet 1 013
`
`US 6,218,930 B1
`
`SES
`
`
`
`mmwoo<BoEmm_
`
`E®EQ_:Um_
`
`
`
`Emax.o2c.mz
`
`
`
`ooSow._m>>on_
`
`Fat
`
`om
`
`._®tm>COOQ2
`
`cam
`
`._ommooo._o_2o_S_
`
`
`
`
`

`
`U.S. Patent
`
`Apr. 17, 2001
`
`Sheet 2 013
`
`US 6,218,930 B1
`
`

`
`U.S. Patent
`
`US 6,218,930 B1
`
`
`3DM_Dmm:_.__>>
`
` wmm_E2n_D%_msmsmm#<oD.526a.EoEm.EE1+EmaGUOZMmwm8<o270UV0}WAmM
`
`m:o;am_m.r
`
`
`
`uogxmmow_oE9.m:o
`
`m.9u.
`
`D
`
`tonww
`
`#mEm£m
`
`
`
`moco.._>>m
`
`
`
`ON_m<,>on_:_m_>_
`
`>_gQ:w
`
`
`

`
`US 6,218,930 B1
`
`1
`APPARATUS AND METHOD FOR
`REMOTELY POVVERING ACCESS
`EQUIPMENT OVER A 10/100 SWITCHED
`ETHERNET NETWORK
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`This application claims the benefits of prior filed, appli-
`cation Ser. No. 60/123,688 filed Mar. 10, 1999.
`FIELD OF THE INVENTION
`
`This invention broadly relates to the powering of 10/100
`Ethernet compatible equipment. The invention more par-
`ticularly relates to apparatus and methods for automatically
`determining if remote equipment is capable of remote power
`feed and if it is determined that the remote equipment is able
`to accept power remotely then to provide power in a reliable
`non—intrusive way.
`BACKGROUND OF THE INVENTION
`
`A variety of telecommunications equipment is remotely
`powered today. Telephones and Network Repeater devices
`are examples of remotely powered equipment. Obviously
`there are many advantages to remotely powering equipment,
`however this technique has not migrated to data communi-
`cations equipment for several reasons. Data communications
`equipment has traditionally required high power levels to
`operate which has made it prohibitive to implement. The
`widely distributed nature as well as the use of shared media
`used in data networks has also made remote power imprac-
`tical.
`
`The desire to add remotely powered devices to a data
`network is being pushed by the convergence of voice and
`data technologies. The advent of IP Telephony, Voice over IP
`and Voice over Packet technologies has brought traditional
`telephony requirements into the data environment. It is not
`desirable to have a phone powered by a local wall trans-
`former. lt is desirable to have a centrally powered system
`that can be protected during a power outage.
`It
`is therefore an object of the invention to provide
`methods and apparatus for reliably determining if a remote
`piece of equipment is capable of accepting remote power.
`It is another object of this invention to provide methods
`and apparatus for delivering remote power to remote equip-
`ment over 10/100 switched Ethernet segments and maintain
`compliance with IEEE 8023 standards.
`SUMMARY OF THE INVENTION
`
`In accord with the objects of the invention an apparatus
`for remotely powering access equipment over a 10/100
`switched Ethernet network comprises: automatic detection
`of remote equipment being connected to the network; deter-
`mining whether the remote equipment is capable of accept-
`ing remote power in a non-intrusive manner; delivering the
`power to remote equipment over the same wire pairs that
`deliver the data signals; automatic detection of remote
`equipment being removed from the network.
`The complete apparatus comprises a data node adapted
`for data switching, an access device adapted for data
`transmission, at
`least one data signaling pair connected
`between the data node and the access device and arranged to
`transmit data therebetween, a main power source connected
`to supply power to the data node, a secondary power source
`arranged to supply power from the data node via the data
`signaling pair to the access device, sensing means for
`
`U1
`
`10
`
`’
`
`30
`
`40
`
`45
`
`50
`
`60
`
`2
`delivering a low level current from said main power source
`to the access device over the data signaling pair and sensing
`a resulting voltage level thereon, and control means respon-
`sive to said voltage level and adapted to control power
`supplied by the secondary power source to said access
`device in response to a preselected condition of the voltage
`level.
`
`The method includes the steps of delivering a low level
`current from the main power source to the access device
`over the data signaling pair, sensing a voltage level on the
`data signaling pair in response to the low level current, and
`controlling power supplied by the secondary power source
`to the access device in response to a preselected condition of
`the voltage level.
`
`DR AWINGS
`
`The invention will be more clearly understood by refer-
`ence to the following description, taken in connection with
`the accompanying drawings, in which:
`FIG. 1 is a simplified schematic diagram of the remote
`power automatic detection system of the present invention,
`shown in conjunction with a single unit of remote access
`equipment connected as part of an Ethernet
`local area
`network,
`FIG. 2 is a simplified schematic drawing of a power feed
`configuration for supplying power to the remote access
`equipment on the local area network, and
`FIG. 3 is a simplified physical layout of a portion of a
`switched Ethernet network segment showing a telephone
`device powered through the network data carrying medium.
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`
`Referring now to FIG. 1 of the drawing, a remote access
`device 10 which is compatible with 10/100 Ethernet require-
`ments is connected through a data communications network
`interface adapter to a high data rate network cable 12.
`Remote access device 10 requires power to carry out its
`operation and includes an internal dc-dc switching supply
`which, in the absence of the present invention, would be
`supplied by an ac transformer adapter plugged in to the local
`110 volt supply. Cable 12 is preferably Category 5 wiring
`such as 100BaseX suitable for 100 Mb/s data communica-
`tions over a switched Ethernet network, and is connected to
`a port in a network data node 14, such as a switch or hub.
`Ethernet frames containing data are transmitted over cable
`12 between node 14 and device 10, and from node 14 to and
`from the network in accordance with selected protocols in a
`conventional manner known in the art.
`
`In accordance with the present invention, a power source
`16, which may be the same as the conventional main power
`supply used to power the node 14, is connected to cable 12
`via lines 18 to supply a power level sensing potential to the
`remote access equipment 10 over one of the cable conduc-
`tors. A return path from remote access equipment 10 is
`connected through a lead 20 to an automatic remote power
`detector, shown generally as 22. Detector 22 includes an
`A/D converter and microprocessor control unit 24, operating
`a detection circuit consisting of a resistor 26, with shunting
`switch 28, both connected in parallel
`to a resistor 30,
`providing a path to ground. Switch 28 is actually an internal
`software controlled switch depicted diagrammatically as
`actuated by operator 32.
`Automatic detection of remote equipment being con-
`nected to the network is accomplished by delivering a low
`
`

`
`US 6,218,930 B1
`
`10
`
`30
`
`40
`
`3
`level current (approx. 20 ma) to the network interface and
`measuring a voltage drop in the return path. There are three
`states which can be determined: no voltage drop, a fixed
`level voltage drop or a varying level voltage drop. If no
`voltage drop is detected then the remote equipment does not
`contain a dc resistive termination, and this equipment is
`identified as unable to support remote power feed. If a fixed
`voltage level is detected then the remote equipment contains
`a dc resistive termination (a “bob smith” is typical for
`Ethernet terminations), and this equipment is identified as
`unable to support remote power feed.
`If a varying voltage level is detected, this identifies the
`presence of dc—dc switching supply in the remote equipment.
`The varying level is created by the remote power supply
`beginning to start up but the low current level is unable to
`sustain the start up. This cycle continues to be repeated
`creating a “sawtooth” voltage level in the return path. When
`this cycle is confirmed, switch S1 is closed which increases
`the power output to the remote equipment. \Vhen the power
`to the remote equipment reaches the proper level the remote
`power supply turns on and the remote equipment becomes
`active. At this point a second, software level, confirmation
`takes place. The remote equipment must respond to a poll
`using a coded response with a unique MAC address. When
`this process is complete the remote equipment is identilled '
`as known access equipment capable of accepting remote
`power.
`Referring now to FIG. 2 of the drawing, a suitable remote
`power supply is shown generally as 34, which may be
`conveniently incorporated into an Ethernet 8 port switch
`card. A first center tap data transformer 36 includes a
`transformer winding 38 with opposite ends connected by
`leads 40, 42 to terminals 6, 3 respectively of an RJ45
`connector 43. A second center tap transformer 44 with a
`transformer winding 46 has its opposite ends connected via
`leads 48, 50 to terminals 2, 1 respectively of the connector
`43. Power feed is through a center tap lead 39 and power
`return is through a center tap lead 45. Inactive terminals 7,
`8 of connector 43 are connected via lead 52 to a resistor 54.
`Inactive terminals 1, 2 of connector 43 are connected via
`lead 56 to a resistor 58. A junction between resistors 54 and
`58 is connected to ground via a capacitor 60.
`Remote power is delivered to the remote equipment over
`the existing data signaling pairs (phantom power feed).
`Although it is typical that all 8 signal leads are delivered to
`remote equipment, only the 4 signaling leads are guaranteed
`in practice. See FIG. 2 for the power feed configuration.
`Once the remote equipment is operating and confirmed as
`a known remote power enabled device,
`the logic circuit
`shown in FIG. 1 begins to look for removal of the remote
`equipment or an overload fault condition. If the measured
`voltage level drops,
`then this indicates that
`the remote
`equipment has been removed and the logic circuit returns to
`the initial hunt state. If an overload condition is detected
`then the logic circuit returns to its initial state. It can then be
`programmed to either wait for the fault state to be cleared or
`continue to cycle through the state machine.
`FIG. 3 illustrates the physical
`layout of components
`corresponding to the schematic diagram of FIG. I. The
`remote access equipment in this case is a telephone 62
`equipped to handle data communications as well as voice
`and is connected through an access node 64 to premises
`wiring 66, comprising a Category 5 Ethernet 100BaseX
`cable of 4 sets of unshielded twisted pairs, which carry both
`data and power to the telephone 62. Wiring 66 is connected
`to one of the ports of an 8 port Ethernet switch 68 which is
`
`45
`
`50
`
`60
`
`4
`powered from a main power supply 70. The Ethernet switch
`card incorporates the automatic remote power detector 22
`discussed in FIG. 1 and the remote power supply 34 dis-
`cussed in FIG. 2. The power is provided over the wiring 66
`both to the remote access node 64 and telephone 62.
`While there is disclosed what
`is considered to be the
`preferred embodiment of the invention, other modifications
`will occur to those skilled in the art.
`What is claimed is:
`1. Apparatus for remotely powering access equipment in
`a data network, comprising:
`a data node adapted for data switching,
`an access device adapted for data transmission,
`at least one data signaling pair connected between the data
`node and the access device and arranged to transmit
`data therebetween,
`a main power source connected to supply power to the
`data node,
`a secondary power source arranged to supply power from
`the data node via said data signaling pair to the access
`device,
`sensing means for delivering a low level current from said
`main power source to the access device over said data
`signaling pair and sensing a resulting voltage level
`thereon, and
`control means responsive to said voltage level and
`adapted to control power supplied by said secondary
`power source to said access device in response to a
`preselected condition of said voltage level.
`2. Apparatus according to claim 1, wherein there are at
`least two data signaling pairs connected between the data
`node and the access device to supply phantom power from
`the secondary power source to the access device, and
`wherein said access device includes a pair of data trans-
`formers having center taps connected for locally powering
`the access device.
`3. Apparatus according to claim I, wherein said prese-
`lected condition comprises a varying “sawtooth”voltage
`level detected by said sensing means which causes said
`control means to increase the power supply from the sec-
`ondary power source to the access device.
`4. Apparatus according to claim 1, wherein the data node
`is an Ethernet switch card incorporating said secondary
`power supply, said sensing means and said control means.
`5. Apparatus according to claim 1, and further including
`a software program associated with said control means and
`arranged to poll the access device to identify itself and
`confirm that it is capable of accepting remote power.
`6. Method for remotely powering access equipment in a
`data network, comprising,
`providing a data node adapted for data switching, an
`access device adapted for data transmission, at least one
`data signaling pair connected between the data node
`and the access device and arranged to transmit data
`therebetween, a main power source connected to sup-
`ply power to the data node, and a secondary power
`source arranged to supply power from the data node via
`said data signaling pair to the access device,
`delivering a low level current from said main power
`source to the access device over said data signaling
`pair,
`sensing a voltage level on the data signaling pair in
`response to the low level current, and
`controlling power supplied by said secondary power
`source to said access device in response to a preselected
`condition of said voltage level.
`
`

`
`US 6,218,930 B1
`
`5
`7. Method according to claim 6, including the step of:
`jncrcasjng pcwcr suppficd 10 Ihc acccss dcvjcc in
`fcspgngc 10 a “§aw]_QQ|_h” V011-agc lcvcl scnscd on {he
`data signaling pair.
`8. Method according to claim 6, including the step of
`polling the access device to identify it and confirm that it is
`capable of accepting remote power.
`
`6
`9. Method according to claim 6, including the step of
`continuing to sense voltage level and to decrease power
`from the secondary power source if voltage level drops on
`the data signaling pair, indicating removal of the access
`5 device.
`
`*
`
`*
`
`*