PCT
`INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`WO 96/23377
`
`WORLD INTELLECfUAL PROPERTY ORGANIZATION
`International Bureau
`
`(51) International Patent Classification 6:
`H04L 1111.0, H04Q 11104, H04M 19/08
`
`(11) International Publication Number:
`
`At
`
`(43) International Publication Date:
`
`I August 1996 (01.08.96)
`
`(21) International Application Number:
`
`PCT/ffi96/00223
`
`(22) International Filing Date:
`
`26 January 1996 (26.01.96)
`
`(30) Priority Data:
`08/379,365
`
`27 January 1995 (27.01.95)
`
`us
`
`INTECOM, INCORPORATED [US/US]; 5057
`(71) Applicant:
`Keller Springs Road, Dallas, TX 75248 (US).
`
`(81) Designated States: AL, AM, AT, AU, AZ, BB, BG, BR, BY,
`CA, CH, CN, CZ, DE, DK, EE, ES, FI, GB, GE, HU, IS,
`W,KE,KG,KP,KR,KZ,LK,LR,LS,LT,LU,LV,MD,
`MG, MK, MN, MW, MX, NO, NZ, PL. PT, RO, RU, SD,
`SE, SG, Sl, SK, TJ, TM, TR, TI, UA, UG, UZ, VN, ARIPO
`patent (KE, LS, MW, SD, SZ, UG), Eurasian patent (AZ,
`BY, KG, KZ, RU, TJ, TM), European patent (AT, BE, CH,
`DE, DK, ES, FR, GB, GR, IE, IT, LU, MC, NL, PT. SE),
`OAPI patent (BF, BJ, CF, CG, CI, CM, GA. GN, ML, MR,
`NE, SN, TD, TG).
`
`(72) Inventors: HUNTER, Richard, K.; Apartment 804, 4815 Published
`With international search report.
`Westgrove Road, Dallas, TX 75248 (US). PLA TI, Richard,
`Before the expiration of the time limit for amending the
`B.; 1111 Ashby Drive, Allen, TX 75002 (US).
`claims and to be republished in the event of the receipt of
`amendments.
`
`(74) Agent: HITI, David, H.; Hitt Chwang & Gaines, P.C., Suite
`225, 275 West Campbell Road, Richardson, TX 75080 (US).
`
`(54) Title: MULTIMEDIA SYSTEM HAVING CENTRAL POWER SOURCE AND DISTRIBUTION SUBSYSTEM
`
`._, W.:'' )r-.----lN+!M>!-+..;.~flP>!-------i I
`
`POIEII--...
`SDU1IC[ 412 ~·.Jf'.r---!to+f*l--11-·~~ - - - - - - - ;
`
`(57) Abstract
`
`Ill!
`
`A power subsystem and method for providing phantom power and third pair power via a computer network bus, the bus including
`first and second conductors. The phantom power subsystem comprises: (1) a power supply having a positive output and a negative output,
`the power supply adapted to provide power via the positive and negative outputs and (2) first and second transformers, each of the first and
`second transformers having a winding, each of the windings having a pair of end taps and a center tap, the first conductor coupled to the
`end taps of the winding of the first transformer to allow data communication therebetween, the second conductor coupled to the end taps
`of the winding of the second transformer to allow data communication therebetween, the positive and negative outputs of the power supply
`coupled to the center taps of the windings of the first and second transformers, respectively, to allow the power supply to transmit the
`power, via the first and second transformers and the first and second conductors, to equipment couplable to the first and second conductors.
`
`SONY EXHIBIT 1025
`
`Page 1 of 75
`
`

`
`FOR THE PURPOSES OF INFORMATION ONLY
`
`Codes used to identify States party to the Per on the front pages of pamphlets publishing international
`applications under the PCf.
`
`AM
`AT
`AU
`BB
`BE
`BF
`BG
`BJ
`BR
`BY
`CA
`CF
`CG
`CH
`Cl
`CM
`CN
`cs
`cz
`DE
`DK
`EE
`ES
`Fl
`FR
`GA
`
`Annenia
`Austtia
`Australia
`Barbados
`Belgium
`Burlcina Fuo
`Bulgaria
`Benin
`Brazil
`Belarus
`Canada
`Central African Republic
`Congo
`Switzerland
`COte d'Ivoire
`Cameroon
`China
`Czecho&lovakia
`Cuch Republic
`Germany
`Denmark
`Eatooia
`Spain
`Finland
`France
`Gabon
`
`GB
`GE
`GN
`GR
`HU
`IE
`IT
`JP
`KE
`KG
`KP
`
`KR
`KZ
`Ll
`LK
`LR
`LT
`LV
`LV
`MC
`MD
`MG
`ML
`MN
`MR
`
`United Kingdom
`Georgia
`Guinea
`Greece
`Hungary
`Ireland
`Italy
`Jlljl8ll
`Kenya
`Kyrgystan
`Democratic People • s Republic
`of Korea
`Republic of Korea
`Kazakhstan
`Liechtenstein
`Sri Lanka
`Liberia
`Lithuania
`LWiembourg
`l..alvia
`Monaco
`Republic of Moldova
`Madagascar
`Mali
`Mongolia
`Mauritania
`
`MW
`MX
`NE
`NL
`NO
`NZ
`PL
`PT
`RO
`RU
`SD
`SE
`SG
`Sl
`SK
`SN
`sz
`TD
`TG
`TJ
`TT
`VA
`VG
`us
`uz
`VN
`
`Malawi
`Mexico
`Niger
`Netherlands
`Norway
`New Zealand
`Poland
`Portugal
`Romania
`Russian Federation
`Sudan
`Sweden
`Singapore
`Slovenia
`Slovakia
`Senegal
`Swaziland
`Chad
`Togo
`Tajikistan
`Trinidad and Tobago
`Ulmine
`Uganda
`United StaleS of America
`Uzbekistan
`VietNam
`
`Page 2 of 75
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`

`
`W096/23377
`
`PCTIIB96/00223
`
`1
`
`MULTIMEDIA SYSTEM HAVING CENTRAL POWER SOURCE
`AND DISTRIBUTION SUBSYSTEM
`
`TECHNICAL FIELD OF THE INVENTION
`
`The present invention is directed,
`
`in general,
`
`to
`
`5 multimedia systems and, more specifically,
`
`to a power
`
`subsystem for a multimedia subsystem and a method of
`
`providing phantom and
`
`third pair power
`
`therefor,
`
`the
`
`subsystem providing a central power source and distribution
`
`of power to equipment comprising the system.
`
`10
`
`BACKGROUND OF THE INVENTION
`
`CUrrently, "Information superhighway" and "multimedia"
`
`are probably
`
`the most often spoken and
`
`least often
`
`understood aspects of
`
`a
`
`coming
`
`revolution
`
`in data
`
`communication. Although issues specific to an information
`
`15
`
`superhighway are beyond
`
`the
`
`scope of
`
`the present
`
`discussion, interactive multimedia systems are very much
`
`within the present scope.
`
`An interactive multimedia system is broadly defined as
`
`a system capable of processing, storing, communicating and
`
`20 coordinating data pertaining to visual information, aural
`
`Page 3 of 75
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`

`
`W096/13377
`
`PCI'/IB96/00223
`
`2
`
`information and other information. Visual information is
`
`generally divided into still picture or graphics and full
`
`motion video or animation categories.
`
`In the vernacular of
`
`those involved in multimedia, such visual information is
`
`5 generically referred to as "video." Aural information is
`
`generally divided into speech and non-speech categories and
`
`is generically
`
`referred
`
`to as
`
`"voice."
`
`"Other
`
`information" is directed primarily to computer data, often
`
`organized in files and records, and perhaps constituting
`
`10
`
`textual and graphical data.
`
`Such computer data are
`
`generally referred to as "data."
`
`To date, multimedia has,
`
`for the most part, been
`
`limited to stand-alone computer systems or computer systems
`
`linked together in a local area network
`
`("LAN") . While
`
`15
`
`such isolated systems have proven popular and entertaining,
`
`the true value of multimedia will become apparent only when
`
`multimedia-capable wide area networks ("WANs") and protocol
`
`systems are developed, standardized and installed that
`
`permit
`
`truly interactive multimedia.
`
`Such multimedia
`
`20
`
`systems will allow long distance communication of useful
`
`quantities of coordinated voice, video and data, providing,
`
`in effect,
`
`a multimedia extension
`
`to
`
`the voice-only
`
`services of the ubiquitous telephone network.
`
`Defining the structure and operation of an interactive
`
`25 multimedia
`
`system
`
`is
`
`a critical first step
`
`in
`
`the
`
`development of such system. Accordingly, before entering
`
`into a discussion herein of more specific design issues, it
`
`is important to discuss more general questions that need to
`
`be resolved concerning design objectives of the system as
`
`Page 4 of 75
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`

`
`W096/23377
`
`PCI'IIB96/00223
`
`3
`
`a whole and
`
`some generally agreed-upon answers
`
`and
`
`specifications.
`
`Interactive multimedia may be
`
`thought of as an
`
`electronic approximation of the paradigm of interactive
`
`5 group discussion.
`
`It involves the interactive exchange of
`
`voice, video and data between two or more people through an
`
`electronic medium in real time. Because of its interactive
`
`and real-time nature, there are some stringent requirements
`
`and
`
`required
`
`services not normally associated with
`
`10 multimedia retrieval systems.
`
`Some of the more obvious
`
`examples of those requirements and services include latency
`( 11 up(cid:173)
`
`conferencing, availability
`
`(transmission delay),
`
`time11) and WAN interoperability.
`
`The evolution of existing private branch exchange
`( 11 PBX 11 ) and LAN topologies towards a composite interactive
`
`15
`
`multimedia system based upon client/server architectures
`
`and isochronous networks is a natural trend. However, to
`
`merge
`
`the disparate mediums of voice, video and data
`
`successfully into a cohesive network requires that three
`
`20
`
`fundamental integration issues be defined and resolved.
`
`of service
`
`QoS
`
`The first of the fundamental integration issues is quality
`( 11 QOS 11 ) .
`and media quality
`services
`communication bandwidth,
`coupling of separate equipment or 11 terminals 11
`together and
`the availability ( 11 up-time 11 ) of the same. QoS parameters
`
`is defined as
`
`the effective
`
`25
`
`are divided into four groups: 1) terminal QoS, 2) network
`
`QoS,
`
`3)
`
`system QoS,
`
`and 4) availability requirements.
`
`Thus, QoS parameters must be defined for both terminal
`equipment ( 11 TE 11 ) and network equipment ( 11 NE 11 ) governing the
`
`Page 5 of 75
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`

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`W096/13377
`
`PCI'IIB96/00223
`
`4
`
`communication of data between the TE.
`
`System QoS
`
`is
`
`derived from a combination of terminal and network QoS.
`
`The suggested values for QoS parameters are considered to
`
`be a practical compromise between required service quality,
`
`5
`
`technology and cost. See, Multimedia Communications Forum
`
`11 MMCF 11
`
`) Working Document
`
`(
`
`11 Architecture and Network QoS 11
`
`,
`
`ARCH/QOS/94-001, Rev. 1.7, MMCF,
`
`(September 1994) and ITU-T
`
`Recommendation I.350 11 General Aspects of Quality of Service
`
`and Network Performance in Digital Networks,
`
`including
`
`10
`
`Integrated Services Digital Networks
`
`( 11 ISDNs 11
`
`)
`
`,
`
`( 1993) .
`
`The following Table I summarizes some suggested parameters
`
`for terminal QoS.
`
`Page 6 of 75
`
`

`
`W096/23377
`
`PCT/IB96/0022J
`
`5
`
`Parameter Type
`
`Parameter Value
`
`Audio Frequency
`Range
`
`3.4kHz
`
`Audio Level
`
`-lOdBmO
`
`5
`
`Audio Encoding
`
`G.711 (8-bit
`pulse code
`modulation
`(II PCM") )
`
`Video Resolution
`
`::: 352x288 (SIF)
`
`Video Frame Rate
`
`::: 20 frames per
`second (fps)
`
`10
`
`Voice/Video
`Intramedia(cid:173)
`Intermedia
`Differential
`Delay
`
`< 100
`milliseconds (ms)
`
`Video Encoding
`
`H.261 & Motion
`Picture Experts
`Group ("MPEG")-1
`
`Parameter
`Explanation
`
`Optimization is
`for voice, and is
`consistent with
`existing Legacy
`voice systems.
`
`Optimization is
`for voice, and is
`consistent with
`Legacy voice
`systems.
`
`Consistent with
`Legacy voice
`systems.
`
`Minimal
`acceptable size
`for video
`conferencing.
`
`Minimal
`optimization for
`detection of
`facial expression
`transitions.
`
`A differential
`delay greater
`than lOOms
`between voice &
`video is
`noticeably
`significant.
`
`H.261 meets WAN
`interoperability,
`MPEG-1 is more
`consistent with
`desktop trends
`and quality
`requirements.
`
`Page 7 of 75
`
`

`
`W096123377
`
`PCf/IB96/00223
`
`6
`
`Parameter Type
`
`Parameter Value
`
`Intramedia
`Latency (TE)
`
`<
`
`lOOms
`
`User Data Rate
`
`~ 64kbps
`
`Data Encoding
`
`HDLC
`encapsulation
`
`Parameter
`Explanation
`
`The delay of the
`TE itself for
`encoding and
`framing purposes.
`
`Minimal
`acceptable data
`bandwidth for
`data sharing
`applications.
`Consistent with
`ISDN Basic Rate
`Instrument
`( "BRI II) .
`
`Consistent with
`isochronous
`service bearer
`channels.
`
`5
`
`Table I - Terminal QoS Parameters
`
`Network QoS parameter requirements consist of those
`
`parts of the system that are between two TE endpoints.
`
`This
`
`includes a portion of the TE itself I
`
`the private
`
`network
`
`(if
`
`required) I
`
`and
`
`the public network
`
`(if
`
`10
`
`required) .
`
`Some of
`
`the requirements
`
`imposed upon the
`
`network QoS are a result of the terminal QoS parameters.
`
`The
`
`following Table
`
`II
`
`summarizes
`
`the network QoS
`
`requirements.
`
`Page 8 of 75
`
`

`
`------------------~=========------------
`
`W096/23377
`
`PCT/IB96/00ll3
`
`7
`
`Parameter
`Value
`
`< SOms
`
`Parameter Type
`
`Intramedia
`Latency (NE)
`
`Parameter Explanation
`
`Intramedia latency is
`the delay between
`source TE transmis-
`sian and destination
`TE reception; i.e.
`the delay of NE.
`
`Network
`Capacity
`
`5
`
`~ 1,536 kbps G.711 Audio (64
`kbps), MPEG-1 Video
`( 1, 344kbps) , HDLC
`data (128kbps) .
`
`Table II - Network QoS Parameters
`
`The system QoS encompasses the terminal and network
`elements. The particular value critical to the system is
`the intramedia latency. The following Table III summarizes
`this value that is the sum of the terminal and network
`values for the same parameter.
`
`10
`
`Parameter Type
`
`Intramedia
`Latency (System)
`
`Parameter
`Value
`
`<
`
`lSOms
`
`Parameter Explanation
`
`Intramedia latency is
`the delay between
`source transmission
`and destination
`reception.
`It
`includes latency
`imposed by the source
`and destination TEs
`as well as the NE.
`These latency values
`might include
`encoding and decoding
`delays, transmission
`delays, and
`adaptation delays.
`
`15
`
`Table III - System QoS Parameters
`
`SUBSTITUTE SHEET (RULE 26)
`
`Page 9 of 75
`
`

`
`W096/l3377
`
`PCf/IB96/00223
`
`8
`
`The system QoS parameter of Intramedia Latency is the
`
`sum of the TE and NE latency.
`
`Intramedia Latency parameter
`
`value is bounded by voice requirements since latent delay
`
`is more readily perceived by
`
`the ear
`
`than
`
`the eye.
`
`5 However, the delay itself is typically a function of video
`
`since it is the component requiring the most
`
`time for
`
`encoding and decoding.
`
`Availability ("up-time") includes several aspects.
`
`In
`
`particular,
`
`the
`
`network
`
`elements
`
`have very strict
`
`10
`
`requirements. These requirements are typical of private
`
`branch exchanges ("PBXs") and other private network voice
`
`equipment, but are very atypical of Legacy LANs. Most LANs
`
`are susceptible to power-losses, single points of failure,
`
`and errant TE.
`
`An
`
`interactive multimedia system must
`
`15 closely follow the availability requirements of the legacy
`
`voice
`
`systems.
`
`The
`
`following Table
`
`IV
`
`summarizes
`
`Availability QoS parameters.
`
`Page 10 of 75
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`

`
`W096/l3377
`
`PCI'/IB96/0022J
`
`9
`
`Parameter Type
`
`Parameter Value Parameter
`Explanation
`
`TE Power
`Requirements
`
`5 watts (W) of
`phantom power
`( 4 8 vo 1 t s
`( v) )
`
`This power
`requirement is
`consistent with
`the ISDN BRI
`requirements and
`will allow the
`least common
`denominator of
`voice to function.
`
`NE Power
`Requirements
`
`5
`
`Uninterruptable
`power supply
`("UPS II)
`
`NE must be UPS
`capable including
`private NE.
`
`Single point of
`failure
`
`12 Users
`
`Error Free
`Seconds Ratio
`( "EFS II)
`
`10
`
`> 99.9%
`
`No more than 12
`users should be
`impacted by a
`single point of
`failure.
`
`Meets requirement
`of random bit
`error rate of 10- 6
`
`•
`
`Table IV - Availability QoS Parameters
`
`The availability
`
`requirements are defined solely
`
`within the context of the private network. Additional
`
`availability parameters are discussed in G.821.
`
`See also,
`
`15 MMCF Working Document "Architecture and Network QOS 11
`
`,
`
`ARCH/QOS/94-001, Rev. 1.7, Multimedia Communications Forum,
`
`Inc., (September 1994) and TR-TSY-000499, Transport Systems
`
`Generic Requirements (TSGR) : Common Requirements, Bellcore
`
`Technical Reference, Issue 3,
`
`(December 1989).
`
`20
`
`The second of the fundamental integration issues is
`
`network services.
`
`Network services
`
`include
`
`transport
`
`Page 11 of 75
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`

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`W09612J377
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`
`10
`
`services, connection management and feature management.
`
`Multimedia communication involves the transmission of data
`
`having more varied characteristics than video, voice or
`
`data in isolation. Therefore,
`
`the manner in which the
`
`5 network transports and manages the flow of video, voice and
`
`data is critical to the efficiency, flexibility and overall
`
`effectiveness of the network.
`
`Transport services can be categorized
`
`into
`
`three
`
`groups: 1) packet, 2) circuit and 3) cell. The following
`10 Table v summarizes different aspects of each of
`
`these
`
`transport services.
`
`Typical
`technology
`
`15 Media
`optimization
`
`Packet
`
`Ethernet®,
`Token Ring®,
`Frame
`Relay®, etc.
`
`Packet data
`
`Circuit
`
`ISDN, T1
`
`Cell
`
`Asynchronous
`Transfer
`Mode
`("ATM")
`
`Isochronous
`data (voice,
`video)
`
`Packet &
`isochronous
`data
`
`Transport
`optimization
`
`Multicast,
`shared
`medium
`operations
`
`Point-point, Point-point,
`full-duplex,
`full-duplex,
`low-cost
`high-speed
`switching
`switching
`
`20
`
`Optimized
`data size
`
`Transport
`Overhead
`
`1500 bytes
`(Ethernet®)
`
`1 byte
`(voice)
`
`4.2% (64
`IP)
`bytes -
`
`none
`
`48 bytes
`
`11.3%
`(6
`bytes -
`AAL1)
`
`Transport
`Methodology
`
`Shared
`
`Switched
`
`Switched
`
`Page 12 of 75
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`

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`W096/23377
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`PCI'IIB96/00223
`
`Packet
`
`Routing
`
`Route
`Methodology
`
`Typical
`Deployment
`
`Widespread. Widespread.
`Deployed as
`Deployed as
`both public
`LAN
`network and
`private NE
`
`11
`
`Circuit
`
`Cell
`
`Signalling
`(circuit
`switching)
`
`Signalling
`(virtual
`circuit
`switching)
`
`Very few
`installation
`s.
`Typically
`deployed as
`private
`backbone
`network
`
`5
`
`Table v - Transport Services
`
`Interactive multimedia
`
`requires
`
`the usage of an
`
`isochronous network because of the QoS requirements for
`
`voice and video. While it is possible to construct a
`
`packet network with sufficient bandwidth, buffering and
`
`10
`
`intelligence
`
`to accommodate synchronous
`
`traffic it is
`
`considered to be prohibitively expensive and unnecessary.
`
`Nevertheless,
`
`both
`
`the
`
`LAN,
`
`PBX
`
`and WAN
`
`require
`
`interoperability.
`
`At some point it is expected that the entire private
`
`15 network
`
`infrastructure will
`
`employ ATM.
`
`This will
`
`transpire upon the occurrence of several events. First,
`
`WANs must adapt to support ATM Points-of-Presence ("POPs").
`
`Second,
`
`the
`
`telephone must disappear
`
`from
`
`the premise
`
`(replaced by an ATM audio device) . Third, packet-based LAN
`
`20 TE must become ATM TE.
`
`Fourth, phantom power must be
`
`supported
`
`to
`
`the ATM TE
`
`(for availability purposes) .
`
`Fifth, an 8kHz synchronous clock must be supported and
`
`Page 13 of 75
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`

`
`W096123377
`
`PCI'/IB96/00223
`
`12
`
`managed by all ATM equipment. Finally, the price of ATM TE
`
`and NE must approach
`
`that of Ethernet®,
`
`ISDN,
`
`and
`
`isoEthernet® equipment.
`
`Regardless
`
`of
`
`the
`
`interim
`
`private
`
`network
`
`5
`
`infrastructure, ATM is the only backbone solution for the
`
`private network.
`
`It is
`
`the only scalable switching
`
`architecture that can transport packet and
`
`isochronous
`
`data. Furthermore, because it is deployed as a backbone,
`
`the aforementioned issues do not apply.
`
`10
`
`Connection management is the process employed by the
`
`private and public network routing functions.
`
`Because
`
`packet routing is a well established and defined process,
`
`it is not discussed further. Connection management within
`
`the confines of an isochronous network for interactive
`
`15 multimedia is a newer technology (albeit with old roots)
`
`and deserves discussion.
`
`Signalling for circuit and cell switching is best
`
`defined by the
`
`ISDN signalling standards
`
`(see, TR-NWT-
`
`000938, Network Transmission Interface and Performance
`
`20 Specification Supporting
`
`Integrated Digital Services
`
`Network
`
`(ISDN) , Bell core Technical Reference,
`
`Issue 1,
`
`(August 1990)), isoEthernet® signalling (see, IEEE Proposed
`
`Standard 802.9a, "Isochronous services with Carrier Sense
`
`Multiple Access with Collision Detection (CSMA/CD) Media
`
`25 Access Control
`
`(MAC) service",
`
`(December 1994)) and ATM
`
`signalling (see, ATM Forum,
`
`"ATM User-Network Interface
`
`Specification - Version 3. 0",
`
`(September 1993) and ITU-T
`
`Recorranendation Q.293x, "Generic Concepts for the Support of
`
`Multipoint
`
`and
`
`Mul ticonnection
`
`Calls";
`
`( 1993) ) .
`
`Page 14 of 75
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`
`Historically,
`
`isochronous networks carry the signalling
`
`channel as an
`
`isochronous channel.
`
`Nevertheless,
`
`the
`
`signalling function can be shown to be better suited to a
`
`packet channel.
`
`A hub/routing function is the
`
`ideal
`
`5
`
`location to perform the bridging between an isochronous
`
`signalling channel and a packet signalling channel.
`
`The
`
`natural packet protocol choice for a signalling channel is
`
`an Internet Protocol ("IETF IP"). Available on most LAN
`
`networks, as well as global routing capability, IP greatly
`
`10 enhances
`
`the
`
`signalling
`
`requirement
`
`of
`
`interactive
`
`multimedia.
`
`Feature management consists of those features provided
`
`by
`
`the private and public network
`
`for
`
`interactivity
`
`purposes. The PBX is followed as a model for interactive
`
`15 multimedia features.
`
`The following Table VI summarizes
`
`some of the more common features.
`
`Page 15 of 75
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`
`System Services
`
`User Services
`
`Maintenance
`
`Account Codes
`
`Buzz Station
`
`Automatic Restart
`
`Authorization
`Codes
`
`Callback
`
`Connection Detail
`Recording
`
`5
`
`Automatic Number Call Forward
`Identification
`
`Default
`Installation
`
`Direct Inward
`Dialing ("DID")
`
`Direct Outward
`10 Dialing ("DOD")
`
`Call Park
`
`Class of Service
`
`Call Pickup
`
`Hot Configuration
`
`Hunt Groups
`
`Call Waiting
`
`Multimedia on
`hold
`
`Do Not
`Disturb/Override
`
`Network Numbering Hold/Consultation
`Hold
`Plan
`
`15
`
`Number Dial Plan Last Number
`Redial
`
`Shared Resource Multiple/Shared
`Call Appearances
`Queuing
`
`System Speed
`20 Dialing
`
`Vacant Number
`Intercept
`
`Conference
`(multiparty)
`
`Transfer
`
`Table VI - Feature Management
`
`The third of the fundamental integration issues is
`
`25
`
`interoperability.
`
`An
`
`interactive multimedia system by
`
`nature
`
`implies
`
`interoperability, because
`
`a multimedia
`
`network as envisioned is too large and far-flung to employ
`
`the equipment of only a single supplier.
`
`Therefore,
`
`standards must be established that allow equipment from
`
`30 different suppliers to interact smoothly.
`
`To this end,
`
`Page 16 of 75
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`15
`
`interoperability must extend
`
`to
`
`transport mechanisms,
`
`signalling and compression standards.
`
`There are certain existing communication technologies
`
`that must be supported and others that are used. A truly
`
`5
`
`interoperable
`
`interactive multimedia
`
`system
`
`should
`
`guarantee that the physical and logical interfaces of each
`
`component adheres to a standard. Prior to 1992, this would
`
`have been almost impossible. The present day affords the
`
`opportunity to evolve the proprietary telephony of the PBX
`
`10 and the proprietary video of the video conferencing systems
`
`into standards-based systems in the same manner that the
`
`data systems evolved from proprietary mainframes to the
`
`standards-based LAN systems of today. The following Table
`
`VII summarizes the required standards of interoperability.
`
`15
`
`Transport
`Standards
`
`isoEthernet®
`(IEEE 802. 9a)
`
`ATM
`
`20
`
`ISDN
`
`Signalling
`Standards
`
`ISDN NI-2
`
`QSIG
`
`Q.2931
`
`H.320
`(Audiovisual)
`
`Compression
`Standards
`
`G. 711, G.722
`(Audio)
`
`H.221 (Video)
`
`MPEG-1 (Video)
`
`Table VII - Interoperability Standards
`
`In
`
`addition
`
`to
`
`the
`
`standards
`
`required
`
`for
`
`communications,
`
`there are other standards relating to
`
`application programming interfaces for terminal and server
`
`25 control. These include Microsoft® Telephony Application
`
`Page 17 of 75
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`16
`
`Programming
`
`Interface
`
`("TAP!®") , Novell
`
`TSAPI®,and
`
`Microsoft® ODBC®.
`
`Having now set the stage with a discussion of general
`
`issues concerning multimedia systems, more specific design
`
`5
`
`issues may now be discussed. The specific design issue of
`
`concern is provision of power to guarantee TE availability.
`
`IEEE draft
`
`standard
`
`802. 9a
`
`provides
`
`for
`
`the
`
`integration of video, voice and data services to a desktop
`
`computer system. A needed step in the evolution of this
`
`10
`
`integration is to provide for a level of service equal to
`
`or greater than that currently available from LAN, PBX and
`
`WAN systems.
`
`In the case of voice services, i.e. telephony, users
`
`have come to expect service under all conditions.
`
`In the
`
`15
`
`PBX realm, this is commonly referred to as "dialtone is an
`
`inalienable right."
`
`Users expect basic voice service
`
`regardless of the state of the desktop computer system,
`
`building power, weather,
`
`time of day and other external
`
`factors.
`
`20
`
`This principal is in concert with the above-mentioned
`
`requirement that power must be supported to the ATM TE for
`
`availability purposes to establish ATM as the foundation
`
`for the private network infrastructure. The TE thus must
`
`support at least voice in case of power or device failure
`
`25 of the client.
`
`Power for the TE can be supplied in one of three ways.
`
`First, a
`
`local (in the office) power supply can supply
`
`power to the TE, much in the same way an uninterruptable
`
`power supply functions
`
`to supply power
`
`to a personal
`
`Page 18 of 75
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`17
`
`computer ("PC") in case of power failure. This is local
`
`powering.
`
`Second, power may be routed through the same
`
`cable employed to carry data through the network. This is
`
`phantom powering and is employed in current
`
`telephone
`
`5
`
`systems. Third, power may be routed through a separate,
`
`dedicated power cable. Since LANs often operate with a two
`
`twisted-pair data bus, this method of delivering power is
`
`often called third pair powering.
`
`Local powering,
`
`though possible,
`
`is
`
`relatively
`
`10 expensive, especially in the case of large multimedia
`
`installations, because a dedicated power supply providing
`
`power back-up must be purchased and coupled to the TE.
`
`Phantom powering has the advantage of not requiring
`
`the installation of a dedicated power cable.
`
`However,
`
`15
`
`since power is carried on the data bus a careful phantom
`
`power scheme must be implemented to avoid problems that may
`
`arise due to interactions between the power and the data,
`
`causing instability and imbalance on the bus and thereby
`
`reducing reliability.
`
`20
`
`Third pair powering has the advantage of separating
`
`the power
`
`from
`
`the data,
`
`thereby avoiding potentially
`
`harmful
`
`interactions.
`
`This also preserves existing
`
`standard bus interface circuitry.
`
`However,
`
`third pair
`
`powering requires a dedicated power cable, increasing the
`
`25 cost of new installations and existing installations where
`
`a dedicated power cable is not already in place.
`
`It is desirable to provide options for both phantom
`
`and third pair powering in the environment of a local area
`
`network without significantly altering the topology of the
`
`Page 19 of 75
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`
`network. Accordingly, what is needed in the art are a
`
`power subsystem and method for a multimedia subsystem that
`
`provide a central power source and distribution of the
`
`power to equipment comprising the system within the context
`
`5 of LAN or isochronous LAN transport mediums.
`
`Page 20 of 75
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`19
`
`SUMMARY OF THE INVENTION
`
`To address the above-discussed deficiencies of the
`
`prior art, it is a primary object of the present invention
`
`to provide power subsystems for providing either phantom or
`
`5
`
`third pair power to equipment coupled to a
`
`local area
`
`network,
`
`including, but not limited to, Ethernet®, Token
`
`Ring®,
`
`ATM
`
`and
`
`isoEthernet®.
`
`The
`
`subsystems allow
`
`equipment coupled to the network to be available even when
`
`the network is not operating due to an absence of local
`
`10 power.
`
`It is a further primary object of the present
`
`invention to remain as compatible as possible with existing
`
`standards for video, voice and data communication.
`
`In the attainment of the above primary objects, the
`
`present invention provides a power subsystem and method for
`
`15 providing phantom power and third pair power via a computer
`
`network backbone,
`
`the bus
`
`including first and second
`
`conductors.
`
`In a first aspect, the present invention provides a
`
`phantom power subsystem comprising:
`
`( 1) a power supply
`
`20 having a positive output and a negative output, the power
`
`supply adapted
`
`to provide power via
`
`the positive and
`
`negative outputs and
`
`(2) first and second transformers,
`
`each of the first and second transformers having a winding,
`
`each of the windings having a pair of end taps and a center
`
`25
`
`tap,
`
`the first conductor coupled to the end taps of the
`
`winding
`
`of
`
`the
`
`first
`
`transformer
`
`to
`
`allow
`
`data
`
`communication therebetween, the second conductor coupled to
`
`the end taps of the winding of the second transformer to
`
`Page 21 of 75
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`

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`20
`
`allow data communication therebetween,
`
`the positive and
`
`negative outputs of the power supply coupled to the center
`
`taps of the windings of the first and second transformers,
`
`respectively, to allow the power supply to transmit the
`
`5 power, via the first and second transformers and the first
`
`and second conductors, to equipment couplable to the first
`
`and second conductors.
`
`In one embodiment, the first and
`
`second conductors are twisted-pair conductors, although
`
`untwisted-pair, coaxial and other conductors are within the
`
`10
`
`scope of the present invention.
`
`Thus,
`
`the present invention,
`
`in this first aspect,
`
`provides a power supply, center-tap transformer combination
`
`allowing power to be introduced into the conductors and
`
`throughout the computer network.
`
`Thus,
`
`the concept of
`
`15 phantom power has been extended significantly to operate
`
`with data-bearing LAN buses. At this point, it should be
`
`noted
`
`that
`
`"conductor"
`
`and
`
`"cable" may
`
`be
`
`used
`
`interchangeably.
`
`It is also apparent that the above first aspect of the
`
`20 present invention provides a phantom powering subsystem
`
`suitable for powering a multimedia system meeting
`
`the
`
`general design criteria set forth in the Background of the
`
`Invention.
`
`In a preferred embodiment of the first aspect of the
`
`25 present invention, the subsystem further comprises third
`
`and fourth transformers, each of the third and fourth
`
`transformers having a winding, each of the windings having
`
`a pair of end taps and a center tap, the first conductor
`
`coupled to the end
`
`taps of
`
`the winding of
`
`the third
`
`Page 22 of 75
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`

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`21
`
`transformer to allow data communication therebetween, the
`
`second conductor coupled to the end taps of the winding of
`
`the
`
`fourth
`
`transformer
`
`to allow data
`
`communication
`
`therebetween, the positive and negative inputs of equipment
`
`5
`
`coupled to the center taps of the windings of the third and
`
`fourth
`
`transformers,
`
`respectively,
`
`to allow
`
`the power
`
`supply to transmit the power, via the first and second
`
`transformers, the first and second conductors and the third
`
`and fourth transformers, to the equipment.
`
`10
`
`The third and fourth transformers allow the equipment
`
`to draw power from the conductors.
`
`In an overall LAN, many
`
`pieces of equipment, each with its own third and fourth
`
`transformers, can take power as well as data from the bus.
`
`Thus,
`
`telephone instruments coupled to the equipment can
`
`15
`
`remain powered even when associated devices are not or in
`
`the event of a power failure.
`
`In a preferred embodiment of the first aspect of the
`
`present invention, the bus comprises a 10Base-T bus. Those
`
`of skill in the art will recognize, however,
`
`that the
`
`20 present invention is also compatible with Ethernet®, Token
`
`Ring®, ATM and isoEthernet® standards.
`
`A lOBase-T bus conventionally comprises two twisted(cid:173)
`
`pair conductors, each used for unidirectional transmission
`
`of data.
`
`Thus,
`
`in this embodiment, one of the twisted
`
`25 pairs is employed for transmitting data from equipment,
`
`while the other of the twisted-pairs is used for receiving
`
`data into the equipment. The present invention preferably
`
`employs each of the twisted-pair conductors as a rail by
`
`which to deliver DC power to the equipment.
`
`Page 23 of 75
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`22
`
`The windings of the first and second transformers may
`
`have
`
`two center taps and may employ a balance circuit
`
`coupling the two center taps of each of the windings of the
`
`first and second transformers to the positive and negative
`
`5 outputs, respectively.
`
`In a manner to be described more
`
`particularly, the balance circuit is designed to correct
`
`any current
`
`imbalances
`
`that may be present
`
`in
`
`the
`
`conductors due to varying impedances therein.
`
`The subsystem may further comprise first and second
`
`10 balance circuits coupling the positive and negative outputs
`
`to the center taps of the windings of the first and second
`
`transformers, respectively. Thus, two balance circuits may
`
`be employed to balance the two conductors against each
`
`other. Of course, those of skill in the art will r