Ulllted States Patent [19]
`Chang et al.
`
`US005991885A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,991,885
`Nov. 23, 1999
`
`[54] METHOD AND APPARATUS FOR
`DETECTING THE PRESENCE ()FA
`REMOTE DEVICE AND PROVIDING
`POWER THERETO
`
`[75] Inventors: Wen F. Chang, Saratoga; Fang C. Yu,
`Fremont, both of Calif.
`
`[73] Assignee: Clarinet Systems, Inc., San Jose, Calif.
`
`[21] Appl' NO‘: 08/872’977
`[22]
`Filed;
`Jun_ 11, 1997
`
`6
`[51] Int. Cl. ...................................................... .. G06F 1/26
`U-S- Cl- ............................................. ..
`[58] Field of Search ....................... .. 395/75001, 750.08,
`395/200; 713/300; 710/62
`_
`References Clted
`U S PATENT DOCUMENTS
`
`[56l
`
`395/75002
`9/1998 McKaughan et al.
`5,802,305
`9/1998 Jung ......................... .. 395/750.01
`5,805,904
`5,845,150 12/1998 Henion ............................. .. 395/750.08
`Primary Examiner—Glenn A. Auve
`Assistant Examiner—David A. Wiley
`Attorney, Agent, or Firm—Gray, Cary, Ware & Freidenrich
`[57]
`ABSTRACT
`
`_
`A network system includes a network that detects the
`presence of a remote terminal connected to a network and
`determines the functional protocol of the remote terminal. If
`the remote terminal is an infrared adapter, the network hub
`provides electrical power to the infrared adapter and con
`tinuauy monitors for the presence of the infrared adaptet
`Upon rernoval of the infrared adapter, the network removes
`electrical power that is applied to a user interface connector
`that connects to the infrared adapter. If another protocol is
`detected for the remote terminal, the network hub commu
`nicates with the remote terminal in that protocol and con
`verts the data to the protocol of the network.
`
`5,652,893
`
`7/1997 Ben-Meir et al. ............... .. 395/750.01
`
`18 Claims, 10 Drawing Sheets
`
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`212-1
`
`10/100
`BASE-T
`COMPUTER
`/
`212-2
`
`TOKEN
`RING
`COMPUTER
`
`219-3
`
`D-Link-1006
`Page 1 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 1 0f 10
`
`5,991,885
`
`LAYER 7-3
`\p
`
`HISHER LAYERS
`139
`
`\
`
`LAYER 2
`\//—\
`
`LDGICALLINKCONTRUL
`[LL91
`ISS
`
`DATA
`TERMINAL
`ESUIRMENT
`[DTE]
`MEDIA ACCESS CCNTRCL /
`IMACI
`I34
`
`LAYER 'l
`\/—\
`
`PHYSICAL LAYER
`132
`
`MEDIUM CERENCANT
`INTERFACE IMCII
`I44
`
`j
`I MEDIA
`ATTACHMENT
`UNIT
`[MALI]
`142
`_/
`
`DTE
`[INTEGRATED
`IVIAU]
`13D
`
`MEDIUM
`\I4C
`
`FIGURE 1
`
`D-Link-1006
`Page 2 (of 19)
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`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 2 0f 10
`
`5,991,885
`
`200
`N
`
`/ 201
`
`208
`
`NETWORK
`
`202
`TWORK HUB J
`kg 0
`
`\
`205
`204
`
`\
`205
`204
`
`/—\
`205
`
`205
`204
`
`204
`
`215
`
`200
`' V
`'
`214
`
`|R
`
`COMPUTER
`
`216
`K
`10/100
`BASE-T
`COMPUTER
`
`216
`/
`10/100
`BASE-T
`COMPUTER
`
`212-1
`
`212-2
`
`2120
`
`FIGURE 2
`
`D-Link-1006
`Page 3 (of 19)
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`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 3 0f 10
`
`5,991,885
`
`BOO
`
`32g]
`
`30g 32% 3&\4
`
`304 '
`
`301
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`
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`212.2
`
`318
`K
`TOKEN
`RING
`COMPUTER
`
`2128
`
`FIGURE 8
`
`D-Link-1006
`Page 4 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 4 0f 10
`
`5,991,885
`
`202
`
`210
`
`x 4'10
`412
`\
`\ PROTOCOL
`RANOLER 2
`
`411
`
`
`
`\/\ 400 RROTOOOL
`
`HANDLER 1
`
`414
`
`FIGURE 42
`
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`208
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`
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`
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`
`RROTOOOL
`RANOLER 1
`
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`410
`
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`
`FIGURE 40
`
`_
`P‘
`
`400
`j
`
`416
`DEVICE
`SENSE
`EOTOR
`
`D-Link-1006
`Page 5 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 5 0f 10
`
`5,991,885
`
`FILTER AND
`TRAN F RMER
`
`—
`
`—
`
`F|LTER AND
`TRANSFORMER
`MODULE
`FIGURE 56
`
`R145
`
`1
`(500-1
`2 C5002
`3
`(500-3
`4
`(500-4
`5
`CEDD-5
`6
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`500-7
`7 #5008
`8 L
`
`FILTER AND
`wgggigm
`— —T
`
`—
`
`FILTER AND
`TRANSFDRNTER
`MODULE
`
`RL145
`CONNECTOR
`1
`5502-1
`2 r5022
`3
`(502-3
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`(502-4
`5
`(502-5
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`K502-6
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`7 ‘5028
`8
`’
`
`K505
`
`_/»5D7
`
`FTDDRE 5b
`
`D-Link-1006
`Page 6 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 6 0f 10
`
`5,991,885
`
`FILTER AND
`IR/Iwgggiym
`
`RJ45
`CONNECTOR
`
`-—
`
`_
`
`_
`
`FILTER AND
`TRANSFORMER
`MODULE
`
`1 ‘@414
`
`(504-2
`2
`(504-3
`3
`4 @414
`
`5 ‘Lg-8i:
`7 —¢——
`8 /_594-8
`
`FIGURE 50
`
`D-Link-1006
`Page 7 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 7 0f 10
`
`5,991,885
`
`fmcm
`
`mmw
`
`mg
`m mqw wwm
`
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`
`mm 255
`
`D-Link-1006
`Page 8 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 8 0f 10
`
`5,991,885
`
`m-mow
`
`O
`
`pm magma
`
`D-Link-1006
`Page 9 (of 19)
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`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 9 0f 10
`
`5,991,885
`
`mdom
`
`5 W551
`
`D-Link-1006
`Page 10 (of 19)
`
`

`
`U.S. Patent
`
`Nov. 23, 1999
`
`Sheet 10 0f 10
`
`5,991,885
`
`7U\2/C)
`
`START
`‘
`
`7C4
`
`CONNECT NETWORKING
`OATA PATH TO
`PROTOCOL HANOLER 2, OR
`UP-LINK CONNECTOR,
`
`TURN OFF
`POWER SUPPLY
`640'
`OUTPUTS “MING
`SICNAL
`615
`
`7C8
`
`\
`
`CONNECT NETWORKING
`DATA PATH TO
`PROTOCOL HANDLER I,
`TURN ON
`
`POWER SUPPLY
`640.
`OUTPUTS
`GENERAL PURPOSE SIGNAL
`613
`
`NO
`
`'N'T'AL
`PRESENCE
`
`_Y_E_5_
`
`CONTINUOUS
`PRESENCE
`
`DETECTION
`PHASE
`
`CONNECTION
`PHASE
`
`FIGURE 7
`
`D-Link-1006
`Page 11 (of 19)
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`

`
`1
`METHOD AND APPARATUS FOR
`DETECTING THE PRESENCE OF A
`REMOTE DEVICE AND PROVIDING
`POWER THERETO
`
`FIELD OF THE INVENTION
`
`This invention relates to networking systems, and more
`particularly, to network hubs and netWork interface adapters
`for automatically and continuously detecting the presence of
`a remote adapter coupled to a netWork tWisted-pair cable,
`providing electrical poWer from a netWork hub to the remote
`adapter via the netWork tWisted-pair cable, creating a multi
`protocol netWorking system, and automatically connecting
`the remote adapter to the appropriate netWork hub.
`
`BACKGROUND OF THE INVENTION
`When personal computers became suf?ciently small to
`alloW user portability, it became necessary to provide con
`nections betWeen a portable computer and a computer
`netWork system. Traditionally, the portable computer uses a
`Personal Computer Memory Card International Association
`(PCMCIA) card for either an Ethernet or Token Ring
`netWork hard Wire connection.
`Recently, both portable computers and computer net
`Works include infrared transceivers that alloW Wireless com
`munication betWeen the portable computer and the computer
`netWork for increased mobility. The computer netWork
`includes a protocol conversion bridge that converts commu
`nicated data betWeen an infrared protocol and a protocol of
`the computer netWork. The protocol conversion bridge is
`coupled to a connector typically near the user’s Work station.
`The connector is then coupled to a netWork hub that is
`centrally located. A dedicated electrical poWer supply
`located near the bridge and the infrared transceiver provides
`electrical poWer to the protocol conversion bridge. The
`dedicated electrical poWer supply increases the system cost
`and requires an AC electrical poWer outlet.
`Several systems provide both electrical poWer and signals
`over a common Wire. For example, conventional telephone
`systems that use 48V on a telephone Wire transmit both
`electrical poWer and communication signals over a single
`pair of lines. US. Pat. No. 5,444,184 describes a system that
`transmits both electrical poWer and loW baud rate signals
`over the same tWisted-pair Wires. An attachment unit inter
`face (AUI) in LAN applications uses dedicated Wires in a
`cable to provide electrical poWer from a data terminal
`equipment (DTE) to an eXternal medium attachment unit
`(MAU) Which could be 50 meters aWay from the DTE. All
`of these systems simply provide electrical poWer over the
`Wires. None of these systems checks or con?rms the type of
`system connected thereto before supplying the electrical
`poWer.
`Standard netWork protocols may be described in an Open
`System Interconnection (OSI) interface standard. One stan
`dard netWork protocol is the Ethernet Which is described in
`IEEE standard 802.3 CSMA/CD, the subject matter of
`Which is incorporated by reference in its entirety. Another
`standard netWork protocol is the Token Ring protocol Which
`is described in ANSI/IEEE standard 802.5, the subject
`matter of Which is incorporated by reference in its entirety.
`Both of these IEEE standards describe the media access
`control (MAC) layer and the physical layer of the OSI
`interface.
`FIG. 1 is a pictorial vieW of the interface layers of the OSI
`standard. For simplicity, layer 3 through layer 7 of the OSI
`are combined as higher layers 139. Layer 2 of the OSI
`
`10
`
`15
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`20
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`25
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`
`5,991,885
`
`2
`interface comprises the data link control (DLC) Which
`includes a logical link control (LLC) layer 138 and a media
`access control (MAC) layer 134. Physical layer 1 of the OSI
`interface comprises several sublayers including an attach
`ment unit interface (AUI). The AUI is speci?ed for a 10
`Mb/s Ethernet but not for a 100 Mb/s Ethernet. A media
`attachment unit (MAU) 142 includes all of the physical
`sublayers other than signaling and coding sublayer. In a
`tWisted-pair cable, the medium dependent interface MDI
`144 is an RJ45 connector.
`Many conventional netWork systems detect either layer 1
`or 2 that the data terminal equipment 1330 supports. This
`detection alloWs the netWork systems to share circuitry,
`connectors, and the medium so that the netWork systems
`may handle multiple protocols. By sharing, the cost of the
`DTE is reduced and the inconvenience or damage is mini
`miZed When misconnection is made to the Wrong connector.
`HoWever, all of these conventional systems presume that the
`DTE conforms to the IEEE Standards. Accordingly, these
`detection systems test only systems that comply With the
`IEEE Standards. Depending on the range of the layers that
`these systems Want to detect, the systems require a different
`degree of involvement and resources includes central pro
`cessing units, softWare codes and ?oW, system bus, memory,
`protocol handler, and transceivers. The system also is pro
`tocol dependent and the DTE must run only the protocols
`that the system can understand. The systems are not
`intended, nor do they function to detect an electronic system
`Which is not in conformance With IEEE Standards.
`US. Pat. No. 5,497,460 discloses a detection mechanism
`that alloWs tWo different media access control layer proto
`cols (Ethernet and Token Ring) to share the same connector
`and medium in the OSI model of FIG. 1. The detection
`scheme requires a sophisticated processing unit that issues a
`protocol dependent MAC frame and physical signals and
`compares a prede?ned status in memory to determine Which
`one of the tWo presumed protocols runs on the tWisted-pair
`cable. The detection scheme cannot communicate With any
`device Which does not conform With Ethernet or Token
`Ring.
`Under the same Ethernet MAC protocol, US. Pat. No.
`5,410,535 describes a device that differentiates betWeen
`mediums that the device is connected to so that the con
`nected devices may share the same connector. The medium
`in this case could be a tWisted-pair cable or AUI for other
`medium types. The control How and logic manufactured in
`silicon are Ethernet physical layer dependent. US. Pat. No.
`5,541,957 includes a separate physical layer logic to alloW
`tWo Ethernet connections operating at different transfer rates
`to share the same connector.
`US. Pat. No. 5,121,482 describes a device that detects the
`connected device independent of netWorking protocol. But
`its detection mechanism relies on the impedance of the data
`signal lines, its detection circuitry is also coupled directly to
`the data signal line, Which may lead to interference or even
`corruption on the communication link When running the
`detection procedure.
`It is desired to have a netWork system that recogniZes
`remote devices connected to a connector of the netWork
`system in real time Without intruding on the normal
`operation, provides appropriate electrical poWer as required
`Without damaging the connected remote device, and auto
`matically connects the device to a netWork hub running an
`appropriate protocol.
`SUMMARY OF THE INVENTION
`The present invention provides a detection circuit for
`detecting the presence of a remote device, Which may or
`may not be a netWork device.
`
`D-Link-1006
`Page 12 (of 19)
`
`

`
`3
`The present invention provides a system for controlling
`the application of electrical poWer to a detected device. The
`system includes a signal generator and a feedback analyZer.
`The signal generator receives a timing signal, a control
`signal, and a select signal. The signal generator provides a
`presence request signal in response to the select signal being
`in a ?rst logic state and provides the control signal in
`response to the select signal being in a second logic state.
`The feedback analyZer is coupled to the detected device and
`provides a presence signal in response to the presence signal
`detected from the coupled device being of a predetermined
`type and being coupled to the output of the signal generator.
`The feedback analyZer provides the select signal in a second
`logic state When such a device is detected and provides the
`select signal of a ?rst logic state When such a device is not
`detected. The feedback analyZer controls the application of
`electrical poWer to the coupled device of a predetermined
`type in response to the present signal.
`The present invention provides a method for applying
`electrical poWer. At a ?rst detection time, a ?rst device is an
`initiator and applies a symmetric bipolar signal to a second
`device. At a second detection time, a feedback signal from
`the second device, based upon the signal supplied by the ?rst
`device at the ?rst detection time, triggers a comparator and
`indicates the successful connection of the second device to
`the ?rst device. Alternatively, the second device may pro
`vide the feedback signal based on another electrical poWer
`source and not based on the symmetric bipolar signal. At a
`third detection time, the ?rst device supplies a current
`limited electrical poWer to the second device. At a fourth
`detection time, the second device uses the electrical poWer
`gained from the ?rst device to sustain its oWn operation also
`use it to derive the feedback signal to replace the original
`signal that is provided by the ?rst device. At a ?fth detection
`time, the ?rst device is freed to remove the applied signal
`state in the ?rst detection time, and use the same line for
`other purpose.
`The present invention provides a netWork system that
`includes a plurality of user interface connectors and ?rst and
`second netWork hubs. Each of the plurality of user interface
`connectors is adapted for coupling to a remote device. The
`?rst netWork hub communicates on a ?rst operational pro
`tocol. The second netWork hub is coupled to the plurality of
`user interface connectors for communicating data betWeen
`devices coupled thereto and is coupled to the ?rst netWork
`hub. The second netWork hub identi?es the operational
`protocol of a coupled device. When the identi?ed opera
`tional protocol of the coupled device is a ?rst operational
`protocol, the second netWork hub communicates data
`betWeen the ?rst and second netWork hubs. When the
`identi?ed operational protocol of the coupled device is a
`second operational protocol, the second netWork hub com
`municates With said coupled device in a second operational
`protocol and identi?es the presence of an adapter of a ?rst
`type coupled to at least one of the plurality of user interface
`connectors and continuously provides electrical poWer to the
`adapter in response to the identi?ed presence of the adapter.
`The second netWork hub stops providing electrical poWer to
`the adapter in response to no identi?ed presence of the
`adapter.
`
`10
`
`15
`
`25
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`35
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`
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`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`FIG. 1 is a pictorial vieW illustrating the interface layers
`of the open system interconnection model.
`FIG. 2 is a block diagram illustrating a netWork system in
`accordance With the present invention.
`
`65
`
`5,991,885
`
`4
`FIG. 3 is a block diagram illustrating a netWork system in
`accordance With another embodiment of the present inven
`tion.
`FIG. 4a is block diagram illustrating the netWork hub of
`the netWork system of FIG. 2 in accordance of the present
`invention.
`FIG. 4b is a block diagram illustrating a netWork hub of
`the netWork system of FIG. 3 in accordance With another
`embodiment of the present invention.
`FIG. 5a is a schematic diagram illustrating a conventional
`10Base-T tWisted-pair cable connection.
`FIG. 5b is a schematic diagram illustrating a conventional
`100Base-TX tWisted-pair cable connection.
`FIG. 5c is a schematic diagram illustrating a conventional
`Token Ring tWisted-pair cable connection.
`FIG. 6a is a schematic diagram illustrating a device
`presence detector that is coupled to a remote adapter of a
`?rst type in accordance With the present invention.
`FIG. 6b is a schematic diagram illustrating a device
`presence detector coupled to a remote adapter of a second
`type in accordance With the present invention.
`FIG. 6c is a schematic diagram illustrating a device
`presence detector coupled to a remote adapter of a third type
`in accordance With the present invention.
`FIG. 7 is a How diagram illustrating the operation of the
`device presence detector of FIGS. 6a—6c in accordance With
`the present invention.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`The methods and systems of the present invention
`instantly and continuously detect the connection status dur
`ing idle or normal operation of the systems. In one embodi
`ment of the present invention, the system, Without the
`presence of a detected netWork adapter, assumes a connected
`device uses a speci?c protocol, such as Ethernet or Token
`Ring. In another embodiment of the present invention, the
`netWork system is con?gured for an infrared (IR) adapter or
`Ethernet and not Token Ring. In such a system, a user
`connector of the system functions With either an IR adapter
`or an Ethernet adapter. In another embodiment of the present
`invention, the netWork system is con?gured for an IR
`adapter or Token Ring, and not for Ethernet. In such a
`system, a user connector of the system functions With either
`an IR adapter or a Token Ring adapter. In yet another
`embodiment of the present invention, the netWork system is
`con?gured for an IR adapter, Token Ring, and Ethernet.
`More particularly, the netWork hub 202 (FIG. 2) and the
`netWork hub 302 (FIG. 3) of the present invention provide
`the electrical poWer to the detected device When the pres
`ence of the detected device is con?rmed, and does not
`provide electrical poWer to the connector and the tWisted
`pair cable When either adapters of another type (such as
`Ethernet 10Base-T, 100Base-TX 100Base-T4, and Token
`Ring adapters) are connected or When no adapter is con
`nected. Since the detected device receives the electrical
`poWer from the detecting device, a separate costly electrical
`poWer supply is not needed. The systems of the present
`invention reduce cost, and eliminate the massive intercon
`nection Wires and the electrical poWer plug in the of?ce.
`FIG. 2 is a block diagram illustrating a netWork system
`200 in accordance With the present invention. The netWork
`system 200 includes a netWork 201 and a plurality of
`computers 212. For clarity, only three computers, 212-1
`through 212-3, are shoWn. The computers 212 may be, for
`
`D-Link-1006
`Page 13 (of 19)
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`

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`5,991,885
`
`5
`example, Workstations, portable computers, desktop PCs, or
`personal digital assistants (PDA).
`The network 201 includes a netWork hub 202, a plurality
`of tWisted-pair cables 205, a plurality of user interface
`connectors 204, and an infrared adapter 206. For simplicity
`and clarity, only four tWisted-pair cables 205 and four user
`interface connectors 204 are shoWn. Also, for clarity, only
`one infrared adapter 206 is shoWn. Of course, the netWork
`201 may include other numbers of netWork hubs 202, hub
`user connectors 208, tWisted-pair cables 205, user interface
`connectors 204, and infrared adapters 206.
`The netWork hub 202 includes a plurality of hub user
`connectors 208 and an up-link connector 210. The up-link
`connector 210 alloWs the netWork 201 to be connected to
`another netWork (not shoWn). The computer 212-1 includes
`a ?rst interface 214 Which is an infrared transceiver. The
`computer 212-1 communicates in a ?rst protocol via the
`infrared transceiver 214 With the infrared adapter 206. In one
`embodiment of the present invention, the ?rst protocol is an
`infrared protocol. The computers 212-2 and 212-3 each
`include a second computer interface 216 that communicates
`in a second protocol. In one embodiment of the present
`invention, the protocol of the computer interface 216 is a
`10Base-T or 100Base-TX protocol. In another embodiment
`of the present invention, the protocol of the computer
`interface 216 is a Token Ring protocol. In one embodiment
`of the present invention, the user interface connectors 204
`are conventional RJ45 connectors.
`The computers 212-2 and 212-3 may be physically con
`nected to the netWork 201 via the hub user connectors 208
`by physical Wire connections, such as tWisted-pair Wires,
`betWeen the respective second computer interfaces 216 and
`the user interface connectors 204. The tWisted-pair cable
`according to one embodiment of the present invention may
`be conventional category 3 or 5 tWisted-pair cable. The Wire
`may be disconnected at the computer 212-2 or 212-3 to
`alloW the user to have portability of the associated computer
`212.
`The netWork 201 communicates With the plurality of
`computers 212 via the user interface connectors 204, using
`the infrared adapter 206 for Wireless communication or
`using the computer interfaces 216 for Wired communication.
`Speci?cally, the computer 212-1 communicates Without
`Wire and instead uses an infrared signal 215 communicated
`betWeen the IR adapter 206 and the IR transceiver 214 of the
`computer 212-1 to communicate With the netWork 201. The
`plurality of computers 212 may communicate With each
`other via the hub user connectors 208 or communicate With
`another netWork via the up-link connector 210.
`The netWork 201, according to one embodiment of the
`present invention, is a Local Area Network (LAN) and may
`link to other netWorks.
`The netWork 201 recogniZes the protocol of computers
`212 coupled to the netWork hub 202 and communicates With
`the computer 212 in the appropriate protocol. The netWork
`201 provides electrical poWer to an IR adapter 206 When the
`IR adapter 206 is coupled to the netWork hub 202, but does
`not provide electrical poWer for other adapter for other
`protocols. If the netWork 201 determines that another type of
`device other than an IR adapter 206 is coupled to a user
`interface connector 204, the netWork 201 does not apply
`electrical poWer. The netWork system 200 provides Wireless
`communication betWeen computers 212 and the netWork
`201. Although the adapter 206 is described herein as oper
`ating With infrared, the adapter 206 may provide Wireless
`coupling other than infrared, such as radio frequency. In
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`such a case, the netWork system 200 may be modi?ed to
`operate With these other means of Wireless coupling or
`combinations thereof.
`Speci?cally, the netWork hub 202 determines Whether a
`remote device is connected to the user interface connectors
`204 and determines the type of the remote device. If an
`infrared adapter 206 is connected to a user interface con
`nector 204, the netWork hub 202 provides electrical poWer
`to the IR adapter 206 in response to such detection, and stops
`providing electrical poWer to the IR adapter 206 in response
`to no detection of the IR adapter 206.
`A user may place a computer 212-1 in the vicinity of the
`IR adapter 206 and communicate With the netWork 201. The
`IR adapter 206 provides bi-directional communication
`betWeen the netWork hub 202 and an IR transceiver 214 of
`the computer 212-1. The netWork hub 202 converts data
`from an IR protocol to the protocol of the netWork and vice
`versa. The netWork hub 202 also converts data from the
`protocol of either of the computers 212-2 or 212-3 into the
`protocol of the netWork and vice versa. Accordingly, the
`netWork hub 202 alloWs communication betWeen any of the
`computers 212 by making the appropriate protocol conver
`sion.
`FIG. 3 is a block diagram illustrating a netWork system
`300 in accordance With the present invention. The netWork
`system 300 includes a netWork 301 and a plurality of
`computers 212. For clarity, only three computers 212-1
`through 212-3 are shoWn. The computers 212-1 through
`212-3 include respective computer interfaces 214, 216, and
`318. The computer interface 318 communicates in a third
`protocol.
`The netWork 301 includes a ?rst netWork hub 302, a
`second netWork hub 303, an optional third netWork hub 304,
`a plurality of hub user connectors 204, and ?rst and second
`pluralities of tWisted-pair cables 205 and 305, respectively.
`The netWork 301 may include additional netWork hubs.
`The netWork hub 302 includes a plurality of hub user
`connectors 308, a plurality of pass-through connectors 309,
`and an up-link connector 310. The netWork hub 303 includes
`a plurality of hub user connectors 320 and an up-link
`connector 322. The netWork hub 304 includes a plurality of
`hub user connectors 324 and an up-link connector 326. The
`tWisted-pair cables 305 couple the pass-through connectors
`309 of the netWork hub 302 to respective hub user connec
`tors 320 of the netWork hub 303. LikeWise, tWisted-pair
`cables 305 couple the pass-through connectors 309 of the
`netWork hub 302 to respective hub user connectors 324 of
`the netWork hub 304.
`The netWork 301 communicates With the computers 212
`in a manner similar to that described above in conjunction
`With the netWork 201 of FIG. 2. HoWever, communications
`Within the netWork 301 differs from communication Within
`the netWork 201. Speci?cally, the netWork hub 302 pro
`cesses data in an infrared protocol and passes through data
`in other protocols to the netWork hubs 303 and 304 for
`processing.
`The ?rst netWork hub 302 determines Whether an infrared
`adapter 206 is coupled to a user interface connector 204, and
`if such an IR adapter 206 is detected, the ?rst netWork hub
`302 converts the data betWeen the protocol of the IR adapter
`206 and the netWork hub 303 in a manner similar to that of
`the netWork hub 202 of FIG. 2. HoWever, if an IR adapter
`206 is not detected, the ?rst netWork hub 302 couples the
`corresponding hub connector 308 to the corresponding pass
`through connector 309 for communication With either the
`second hub 303 or the third hub 304. The netWork hub 302
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`does not process the data from the adapter. Hence, the ?rst
`network hub 302 merely passes data communicated between
`the second network hub 303 or the third network hub 304
`and the computer 212 without further processing.
`The network hub 302 implements a “pass through” of
`network data to allow the system to use conventional
`network hub 303 and/or 304 to support a standard network
`protocol such as Ethernet and/or Token Ring. In one
`embodiment of the present invention, the network 301 is
`coupled only to a computer that is in one of two protocols,
`for example, an infrared protocol and an Ethernet protocol.
`The present invention allows a user using an existing
`network hub to establish a multiple protocol network system
`301 for infrared communication, Ethernet and/or Token
`Ring. Multiple networking protocols share the same con
`nector 204. Reusing eXisting conventional hubs and sharing
`the same connector reduces the system cost and increases
`the convenience of network access.
`FIG. 4a is a block diagram illustrating the network hub
`202 in accordance with the present invention. The network
`hub 202 includes a plurality of hub user connectors 208, an
`up-link connector 210, connection path 402, networking
`data path 404, detection path 406, ?rst and second protocol
`handlers 408 and 410, respectively, networking data path
`411 and 412, a plurality of device presence detectors 414,
`and select signal path 416.
`The networking data path 404 couples the hub user
`connector 208 to a ?rst terminal of the connection path 402.
`The detection path 406 couples the device presence detector
`414 to the hub user connector 208. The ?rst and second
`protocol handlers 408 and 410, respectively, are coupled to
`respective second and third terminals of the connection path
`402. The networking data path 411 couples the ?rst and
`second protocol handlers 408 and 410. The networking data
`path 412 couples the second protocol handler 410 to the
`up-link connector 210. The select signal path 416 couples
`the device presence detector 414 to the connection path 402.
`The device presence detector 414 provides a presence
`request signal on the detection path 406 which is applied to
`the hub user connector 208 for determining whether an
`infrared adapter 206 is coupled to the hub user connector
`208. If an infrared adapter 206 is not coupled to the hub user
`connector 208, the device presence detector 414 applies a
`signal to the select signal path 416 that selectively couples
`the hub user connector 208 through the connection path 402
`to the second protocol handler 410 which communicates
`with a computer 212 connected to hub user connector 208 in
`the second protocol. Communication with another network
`(not shown) by the second protocol handler 410 is via the
`up-link connector 210. On the other hand, if the infrared
`adapter 206 is coupled to the hub user connector 208, the
`device presence detector 414 provides a select signal on the
`select signal path 416 to couple the hub user connector 208
`through the connection path 402 to the ?rst protocol handler
`408. The ?rst protocol handler 408 may communicate with
`another network (not shown) via the networking data paths
`411 and 412, and the up-link connector 210.
`The ?rst protocol handler 408 performs the conversion
`between the ?rst protocol and the second protocol, and also
`performs repeater or switching functions of the ?rst protocol
`among the user connectors 208 with IR adapters 206. The
`second protocol handler 410 performs repeater or switching
`functions of the second protocol among up-link connector,
`the ?rst protocol handler 408, and user connectors 208,
`without IR adapters 206. Connection paths 402 provide
`networking paths between the ?rst protocol handler 408 and
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`user connectors 208 with IR adapters 206, and the network
`ing paths between the second protocol handler and user
`connectors 208 without IR adapters 206. Networking path
`411 allows both protocol handlers 408 and 410 to share the
`components for the up-link path.
`FIG. 4b is a block diagram illustrating the network hub
`302 in accordance with the present invention. The network
`hub 302 includes a plurality of hub user connectors 308, a
`plurality of pass-through connectors 309, an up-link con
`nector 310, connection path 402, networking data path 404,
`detection path 406, protocol handler 408, a plurality of
`device presence detectors 414, select signal path 416 and
`networking data path 418.
`The networking data path 404 couples the hub user
`connector 308 to a ?rst terminal of the connection path 402.
`The detection path 406 couples the device presence detector
`414 to the hub user connector 308. The protocol handler 408
`is coupled to a second terminal of the connection path 402.
`The networking data path 418 couples the protocol handler
`408 to the up-link connector 310. The pass-through connec
`tor 309 is coupled to a third terminal of the connection path
`402. The select signal path 416 couples the device presence
`detector 414 to the connection path 402.
`The device presence detector 414 provides a presence
`request signal on the detection path 406 which is applied to
`the hub user connector 308 for determining whether an
`infrared adapter 206 is coupled to the hu