(12) United States Patent
`US 7,203,186 B1
`(10) Patent No.:
`Fuller et al.
`Apr. 10, 2007
`(45) Date of Patent:
`
`US007203186B1
`
`
`
`(54) SYSTEM AND DEVICE FOR INTEGRATING
`IP AND ANALOG TELEPHONE SYSTEMS
`
`(76)
`
`Inventors: William H. Fuller, 3508 Bradford Dr.,
`Richardson, TX (US) 75082; Son T.
`Tran, 14815 Woodbriar Dr., Dallas, TX
`(US) 75248
`
`( *
`
`Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 1045 days.
`
`(21 App1.No.: 09/723,099
`
`(22
`
`Filed:
`
`Nov. 27, 2000
`
`(51
`
`(58
`
`Int. Cl.
`(2006.01)
`H04L 12/66
`(52 US. Cl.
`...................... 370/352; 370/352; 370/401;
`370/419; 370/431; 379/221.02
`Field of Classification Search ................ 370/352,
`370/353, 354, 355, 356, 235, 401, 419, 431;
`379/221.02; 704/270.1; 710/72
`See application file for complete search history.
`
`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`6,119,179 A *
`6,205,120 B1 *
`6,282,192 B1*
`
`............ 710/72
`9/2000 Whitridge et al.
`. 370/235
`3/2001 Packer et a1.
`.......
`
`............. 370/352
`8/2001 Murphy et al.
`
`6,404,764 B1*
`6,654,722 B1 *
`6,661,785 B1 *
`6,718,030 B1 *
`6,760,324 B1 *
`2004/0090954 A1*
`
`................. 370/352
`6/2002 Jones et a1.
`11/2003 Aldous et a1.
`.. 704/270.1
`
`............... 370/352
`12/2003 Zhang et a1.
`.......... 379/221.02
`4/2004 Turner et a1.
`
`7/2004 Scott et a1.
`......... 370/352
`5/2004 Zhang et a1.
`............... 370/352
`
`* cited by examiner
`
`Primary ExamineriJean Gelin
`Assistant Examinerilnder Pal Mehra
`
`(74) Attorney, Agent, or Firm7Wood, Herron & Evans,
`LLP
`
`(57)
`
`ABSTRACT
`
`A system and a call forwarding manager device for provid-
`ing Internet telephony to a subscriber’s premises via the
`subscriber’s Internet connection, facilitated by the subscrib-
`er’s analog telephone connection. Incoming analog tele-
`phone calls are received by the call forwarding manager
`connected to the subscriber’s analog telephone line, which
`responds by generating a request for service from a voice
`gateway, which may be remotely located. The voice gateway
`then generates an Internet telephone connection from the
`voice gateway to an Internet protocol telephone owned by
`the subscriber, and then connects the analog telephone call
`via the voice gateway to the Internet protocol telephone via
`the subscriber’s Internet connection.
`
`33 Claims, 4 Drawing Sheets
`
`78
`
`lé
`
`
`
`VOICE
`DSLAM
`GATEWAY
`
`
`
`
`
`ll—II CENTRAL .l
`
`OFFICE
`SWITCH
`
`
`
` IP
`
`
`
`IP
`TELEPHONE
`
`
`
`
`TELEPHONE
`
`/5
`
`IP
`TELEPHONE
`
`78
`
`IP
`TELEPHONE
`
`75
`
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`1
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`

`

`U.S. Patent
`
`Apr. 10, 2007
`
`Sheet 1 of 4
`
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`203
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`U.S. Patent
`
`Apr. 10, 2007
`
`Sheet 2 of 4
`
`US 7,203,186 B1
`
`FIG. 2A
`
`VoIP CALL TERMINATED AT
`CALL MANAGER
`
`(DESTINATION IP ADDRESS IS
`ROUTED TO CALL MANAGER).
`102
`
`CALL MANAGER
`
`
`RINGS DESTINATION IP
`TELEPHONE USING
`H.323IH.245 PROTOCOL.
`104
`
`
`INCOMING VOIP CALL
`(H.323/H.245) FROM
`
`
`INTERNET TO IP
`TELEPHONE.
`
`100
`
`
`
`
`
`
`
`IP TELEPHONE
`IP TELEPHONE
`
`
`BUSY OR DOES NOT
`ANSWERS CALL.
`
`ANSWER.
`110
`
`106
`
`V
`
`
`CALL MANAGER TERMINATES
`H.323/H.245 CONNECTION TO INCOMING
`
`108
`
`CALL, OR PROVIDES ADVANCED
`SUBSCRIBER SERVICES (PICK GROUPS,
`HUNT GROUPS, FORWARDING, VOICE
`MESSAGING, ETC.).
`
`CALL MANAGER RELAYS
`ANSWER TO CALLER
`OVER INTERNET.
`112
`
`
`
`
`
`
`
`
`VOICE DATA EXCHANGED
`BETWEEN CALLER AND CALLED IP
`
`
`TELEPHONE USING RTP/RTCP
`
`
`OVER UDP PROTOCOL ACROSS
`
`
`THE INTERNET, OR (FOR ATM/DSL)
`
`
`008 AND NATIVE H.323/ATM.
`114
`
`
`3
`
`

`

`U.S. Patent
`
`Apr. 10, 2007
`
`Sheet 3 of 4
`
`US 7,203,186 B1
`
`FIG. 23
`
`INCOMING ANALOG/POTS
`
`
`CALL FROM PSTN TO IP
`
`
`TELEPHONE.
`120
`
`ANALOG CALL IS TERMINATED
`AT CFM IDNIS OF CALL IS
`ASSIGNED AT TELCO SWITCH
`TO SUBSCRIBER POTS LINE).
`122
`
`
`
`
`
`
`CFM CAPTURES DNIS (AND
`
`
`OPTIONALLY ANI) OF
`INCOMING CALL.
`1 24
`
`
`
`CFM GENERATES VOIP
`
`REQUEST MESSAGE TO
`
`CALL MANAGER ALONG
`
`WITH DNIS AND ANI USING IP
`PROTOCOL.
`
`126
`
`
`CALL MANAGER USES TAPI
`CALL MANAGER USES CALL
`
`
`INTERFACE TO INSTRUCT
`FORWARDING SERVICE TO
`
`
`TELCO SWITCH TO CIRCUIT
`INSTRUCT TELCO SWITCH
`
`
`SWITCH CALL TO VOICE
`CIRCUIT SWITCH CALL TO
`
`
`GATEWAY.
`_ VOICE GATEWAY.
`
`
`128
`129
`
`
`
`
`VOICE GATEWAY TERMINATES
`ANALOG/POTS CALL.
`
`
`CALL MANAGER USES PRIOR SETUP
`
`(ESTABLISHED, E.G., BY SUBSCRIBER VIA
`
`WEB INTERFACE) OR ACCESSES SETUP
`INFORMATION FROM SUBSCRIBER
`COMPUTER SYSTEM.
`
`130
`
`CALL MANAGER
`CALL MANAGER PERFORMS
`
`IDENTIFIES SPECIFIC IP
`
`AUTOMATIC CALL
`
`
`TELEPHONE ASSIGNED
`DISTRIBUTION BASED UPON
`
`
`DNIS ANDIOR ANI.
`TO DNIS.
`
`134
`132
`
`
`
`
`CALL MANAGER DELIVERS
`MGCP CONNECT REQUEST
`TO VOICE GATEWAY
`IDENTIFYING IP TELEPHONE.
`
`136
`
`CALL MANAGER
`
`RINGS DESTINATION IP
`
`TELEPHONE USING
`
`H.23ZIH.245 PROTOCOL.
`140
`
`
`
`
`
`
`IP TELEPHONE
`
`
`BUSY OR DOES NOT
`ANSWER.
`
`
`142
`
`
`CALL MANAGER ENDS
`
`
`MGCP CONNECT REQUEST,
`TAKES APPROPRIATE
`
`
`
`ACTION ON INCOMING CALL.
`144
`
`
`IP TELEPHONE
`ANSWERS CALL.
`146
`
`CALL MANAGER
`
`
`NOTIFIES VOICE
`GATEWAY USING MGCP
`
`
`OF CONNECTION.
`150
`
`
`VOICE DATA EXCHANGED
`
`
`BETWEEN CALLER AND CALLED
`IP TELEPHONE USING RTPIRTCP
`
`
`OVER UDP PROTOCOL OR 005
`AND NATIVE H.3231ATM.
`
`
`152
`
`
`4
`
`

`

`U.S. Patent
`
`Apr. 10,2007
`
`Sheet 4 of4
`
`US 7,203,186 B1
`
`FIG. 20
`
`OUTGOING CALL FROM IP
`TELEPHONE AT
`SUBSCRIBER.
`160
`
`HMS/H.245 CONNECTION
`ESTABLISHED TO CALL
`MANAGER.
`162
`
`CALL MANAGER EVALUATES
`DESTINATION ANALOG/POTS
`TELEPHONE NUMBER, OR
`PROVIDES/ACCESSES ILS NAME
`SERVICE FOR VolP DESTINATION.
`1S4
`
`
`
`
`
`CALL MANAGER ELECTS
`ROUTING PREFERENCE
`
`
`BASED UPON DESTINATION, TIME,
`
`DAY, 005 OR SUBSCRIBER
`
`PREFERENCES.
`166
`
` V
`
`CALL TO BE
`CALL ROUTED
`CALL ROUTED USING
`
`ROUTED USING
`USING PUBLIC
`PRIVATE INTRANET OR
`TELCO SWITCH.
`INTERNET.
`LEASED INTRANET.
`
`163
`177
`
`.._W______J
`
`CALL MANAGER DELIVERS
`
`CALL MANAGER DELIVERS
`CALL TO REMOTE CALL
`
`
`
`MANAGER FOR DESTINATION
`MGCP CONNECT REQUEST TO
`
`
`VOICE GATEWAY IDENTIFYING
`REGION, AND REMOTE CALL
`
`IP TELEPHONE.
`
`MANAGER DETERMINES
`
`
`170
`DESTINATION ROUTING.
`
`
`178
`
`
`VOICE GATEWAY INITIATES
`
`1,,
`ANALOG/POTS
`H.232/H.245 CONNECTION
`MT” 'P TELEPHONE RINGS
`DETINATION
`DESTINATION
`SWITCH.
`DESTINATION VIA TELCO
`1&0
`'
`135
`'
`
`112
`
`
`
`
`REMOTE CALL
`
`
`MANAGER RINGS
`DESTINATION IP TELEPHONE
`
`USING H.323IH.245
`
`PROTOCOL.
`
`
`
`190
`
`194
`
`VOICE DATA EXCHANGED
`BETWEEN CALLING IP TELEPHONE
`AND VOICE GATEWAY USING
`RTPIRTCP OVER UDP PROTOCOL
`OR 005 AND NATIVE H.323/ATM.
`174
`
`REMOTE CALL MANAGER
`DELIVERS MGCP CONNECT
`REQUEST TO REMOTE VOICE
`GATEWAY IDENTIFYING IP
`TELEPHONE.
`182
`
`REMOTE VOICE GATEWAY
`INITIATES H.232/H.245
`CONNECTION WITH IP
`TELEPHONE, RINGS DESTINATION
`VIA REMOTE TELCO SWITCH.
`184
`
`VOICE DATA EXCHANGED
`BETWEEN CALLING IP TELEPHONE
`AND REMOTE VOICE GATEWAY
`USING RTP/RTCP OVER UDP
`PROTOCOL OR 005 AND NATIVE
`H.323lATM.
`156
`
`IP TELEPHONE
`BUSY OR DOES NOT
`ANSWER.
`192
`
`IP TELEPHONE
`ANSWERS CALL.
`196
`
`CALL MANAGER RELAYS
`REMOTE CALL MANAGER
`ANSWER TO CALLING IP
`
`TAKES APPROPRIATE
`TELEPHONE OVER
`ACTION ON INCOMING
`
`INTERNETIINTRANET.
`CALL.
`
`198
`
`
`
`VOICE DATA EXCHANGED
`
`BETWEEN CALLING IP TELEPHONE
`
`
`AND CALLED IP TELEPHONE USING
`RTPIRTCP OVER UDP PROTOCOL
`
`
`OR 005 AND NATIVE H.323lATM.
`200
`
`
`5
`
`

`

`US 7,203,186 B1
`
`1
`SYSTEM AND DEVICE FOR INTEGRATING
`IP AND ANALOG TELEPHONE SYSTEMS
`
`FIELD OF THE INVENTION
`
`The present invention relates to systems for providing
`telephony Via the Internet and Via legacy POTS telephone
`equipment.
`
`BACKGROUND OF THE INVENTION
`
`The telephone has become a nearly universal appliance in
`modern homes and business. While other communications
`media such as the Internet and satellite and radio commu-
`
`nications have advanced, the telephone remains the most
`popular instrument for communication today. Unfortunately,
`telephone technology has not been substantially enhanced
`since its introduction. Telephone connections continue to use
`analog electrical signal transmission over twisted-pair wires,
`between individual telephone terminals. While substantial
`advancements have been made in the transmission of tele-
`
`including the use of sophisticated digital
`phone signals,
`switching, digital compression and decompression and digi-
`tal transmission, telephone terminals remain analog devices
`connected to standard analog POTS telephone lines. Mean-
`while, other communications media, such as the Internet,
`radio and satellite have evolved utilizing digital technology,
`which substantially enhances the flexibility of those com—
`munication systems, while also improving the quality of
`transmission.
`
`Recently, with the promulgation of the voice over IP
`protocol H.323 (VoIP), and the emergence of H.323 com-
`patible software such as “NetMeeting”, digital Internet tele-
`phony has become increasingly popular. Digital Internet
`telephony is accomplished by established a VoIP connection
`via an existing Intemet connection, using the H.245 call
`management protocol; and then initiating an exchange of
`information between terminals compatible with the H.323
`communication standard.
`
`VoIP terminals typically are computer systems having
`Internet connections available for established H.323 com-
`
`munication. However, more recently, stand alone VoIP tele-
`phone sets have been developed, which are attachable to an
`Internet connection. Furthermore, hand sets are available for
`use with computer systems to facilitate the use of the
`computer system and its Internet connection to perform VoIP
`telephony. Using these devices, VoIP telephony has become
`increasingly popular. This popularity is in no small part due
`to the lack of communication surcharges on traffic passed
`over the Internet, as compared to the toll based charges for
`standard telephone service performed via local area tele-
`phone and long distance telephone carriers.
`A difficulty with VoIP telephony is the need to provide
`standard POTS telephone connectivity to environments in
`which digital telephones are in use. A VoIP telephone is not
`readily configurable to operate as a standard analog tele-
`phone,
`to send and receive calls using POTS telephone
`standards. Although VoIP telephony is expected to become
`widely used as a method for telephone communication, it
`will be necessary for VoIP telephony to coexist with preex-
`isting POTS telephony systems for a substantial period of
`time to come. Therefore,
`to convert completely to VoIP
`telephony, it is necessary to adapt VoIP telephones to operate
`properly utilizing standard POTS telephone service.
`The most popular environment in which VoIP telephony
`has been used,
`is large corporate campuses or other sub-
`stantial installations. In these environments, VoIP telephony
`
`2
`
`may be used within the campus, and communications to
`outside VoIP or POTS telephone devices can be managed
`through a central point for the entire installation. VoIP/POTS
`interfacing and management requires the use of specialized
`hardware devices known as a voice gateway and call man-
`ager.
`A voice gateway (also known as a media gateway) is a
`specialized telephone hardware device including analog to
`digital and digital to analog conversion systems, that convert
`an analog POTS telephone line to be connected to one of a
`number of Internet VoIP telephone sets, so that outbound
`calls may be originated from a VoIP telephone set and
`terminated via the publicly switched telephone network, and
`inbound calls from the publicly switched telephone network
`can be delivered as VoIP calls to an appropriate telephone.
`A voice gateway thus permits VoIP telephones to send and
`receive POTS analog telephone calls. Furthermore, a voice
`gateway may be used to permit POTS analog telephones to
`send and receive VoIP Internet telephone calls using the
`same hardware of the voice gateway. Thus, a voice gateway
`is installed at a corporate campus or other substantial
`installation, to permit use of VoIP telephones and legacy
`POTS telephone sets throughout the installation, with the
`voice gateway providing interface between the publicly
`switched telephone network, an Internet connection, and
`each of the telephones in the corporate campus.
`A voice gateway is typically installed along with a call
`manager (also known as a call agent or media gateway
`controller) which is responsible for managing the activities
`of the voice gateway. The call manager includes routing
`tables identifying the manner in which incoming and out-
`going POTS analog and VoIP digital telephone calls should
`be routed. The call manager utilizes these routing tables to
`instruct the voice gateway to perform appropriate actions to
`connect telephone calls to their desired destinations.
`The use of voice over IP or VoIP telephony has been
`limited thus far to corporate campuses and other large
`installations, for the reason a voice gateway and a call
`manager are complex and expensive hardware devices. The
`expense of these devices can only be justified when the
`potential cost savings from the use of VoIP telephony, will
`exceed the expense of the voice gateway and call manager.
`Normally this is possible with large installations where the
`voice gateway and call manager can be shared by a large
`number of telephone systems that are under common own-
`ership.
`Recently, a number of services have been introduced for
`the purpose of facilitating individual or small corporate use
`of VoIP telephony. For example, a service known as DialPad
`has been established for use by users with computer systems
`capable ofVoIP telephony. According to the DialPad system,
`a user having an independent Internet connection connects
`to the DialPad Internet site and delivers a VoIP address or
`
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`standard analog POTS telephone number to the DialPad
`server. The DialPad server is connected to both a voice
`
`gateway and a call manager, in turn connected to the Internet
`backbone and to the publicly switched telephone network at
`one or a number of local areas. The server is capable of
`delivering a VoIP telephone call to a VoIP telephone recipi—
`ent via Internet connections and is also able to utilize the
`
`voice gateway to translate a VoIP telephone connection from
`VoIP to standard POTS telephone service for delivery to a
`standard POTS telephone number. DialPad thus permits a
`individual or small business user to perform VoIP telephony
`and POTS telephony over a single Internet connection,
`however such a user may not receive telephone connections,
`but may only originate.
`
`60
`
`65
`
`6
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`

`

`US 7,203,186 B1
`
`3
`A second service, provided to cellular telephone users by
`Ericsson,
`is known as Phone Doubler. This service will
`deliver telephone calls received at a standard POTS tele-
`phone number to a VoIP telephone set, provided that VoIP set
`is currently connected through an ISP and Internet connec-
`tion. Thus, this service permits inbound POTS analog tele-
`phone connections to be routed to a VoIP telephone on an
`individual basis. However,
`this service does not permit
`outbound telephone communication.
`Athird service of this kind is known as Pagoo.com. In this
`service, a subscriber obtains a standard POTS telephone
`number which is owned by Pagoo and is terminated at
`Pagoo’s telephone server. An inbound dialing party connects
`to Pagoo’s server and provides a three digit extension
`identifying a specific subscriber. This three digit extension is
`used to route the inbound telephone connection to either a
`VoIP connection at a computer or a standard analog POTS
`connection at a subscriber-specified telephone number. To
`maintain connectivity using the Pagoo system, a subscriber
`must log in to the server and register a telephone number or
`computer Internet address before telephone calls may be
`received. A dedicated VoIP telephone may not be used with
`the Pagoo system for the reason that it cannot be logged into
`the server. Furthermore, the Pagoo system does not support
`outbound telephony, but only inbound telephony using a
`Pagoo telephone number and a three digit extension.
`It can be seen by the foregoing, that the Internet telephony
`options available to small business and residential users, are
`substantially limited. A need therefore exists for a method-
`ology and system that permits the use of Internet telephony
`by residences and small business in a manner directly
`analogous to the current use of analog POTS telephone
`service, including inbound and outbound service, multiple
`inbound and outbound lines, and all other conveniences and
`features of modern POTS analog telephony.
`
`SUMMARY OF THE INVENTION
`
`The invention satisfies this need by providing Internet
`telephony to a subscriber’s premises via the subscriber’s
`Internet connection, facilitated by the subscriber’s analog
`telephone connection. Incoming analog telephone calls are
`received by a call forwarding manager connected to the
`subscriber’s analog telephone line, which responds by gen-
`erating a request for service from a voice gateway, which
`may be remotely located. The voice gateway then generates
`an Internet telephone connection from the voice gateway to
`an Internet protocol telephone owned by the subscriber, and
`then connects the analog telephone call via the voice gate-
`way to the Internet protocol telephone via the subscriber’s
`Internet connection.
`
`In the described embodiment, the call forwarding man-
`ager is located at the subscriber’s premises, and connected
`to an analog telephone line at the subscriber’s premises. The
`voice gateway is remote from the subscriber’s premises. In
`this approach, the voice gateway may be utilized by multiple
`subscribers simultaneously to provide conversion between
`Internet telephony and analog telephony standards,
`thus
`spreading the cost of that device across multiple subscribers.
`In this embodiment, the voice gateway is managed by a
`call manager, which receives requests for service from the
`call forwarding manager, and establishes Internet telephone
`connections from the voice gateway to the Internet protocol
`telephone for use by the voice gateway. The analog tele-
`phone call is connected to the voice gateway by delivery of
`one or more of TAPI, JTAPI, SCTP, or proprietary interface
`commands to a telecommunications exchange switch. In the
`
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`described embodiment, the call manager performs a data
`driven call management application, which can include
`providing enhanced services to the subscriber including
`establishing pick groups, hunt groups, call forwarding and
`voice messaging for the Internet protocol telephones of the
`subscriber.
`
`To facilitate such advanced functions, in this embodiment
`the call forwarding manager receives dialed number infor-
`mation service (DNIS) data regarding an analog telephone
`call and forwards the DNIS data as part of requesting
`gateway service. The DNIS data may be used, for example,
`in identifying an Internet protocol telephone as a recipient of
`an analog telephone call. The call forwarding manager may
`also receive automatic number identification (ANI) data
`regarding an analog telephone call and forward it as part of
`a request for service. The ANI data can also be used in
`identifying an Internet protocol telephone as a recipient of
`the analog telephone call. DNIS and ANI data may also be
`used in voice response systems implemented by the call
`manager.
`
`Aspects of the invention include the above-described
`method and apparatus for performing analog/IP telephony,
`as well as the call forwarding manager per se. The call
`forwarding manager comprises an analog telephone connec-
`tion for connection to an analog telephone line to capture
`one or more of dialed number information service data or
`
`automatic number identification data, and a digital commu-
`nications connection for delivering a request for service
`including one or more of the dialed number information
`service data or automatic number identification data.
`
`The digital communications interface of the call forward-
`ing manager may be a serial connection such as USB,
`Firewire or Ethernet, or may be a parallel connection such
`as IEEE-488, or PCI, ISA (in the latter two cases, the call
`forwarding manager may be in the form of a PC card).
`The call
`forwarding manager may also incorporate
`advanced functionality such as firewall and VPN systems for
`managing communications via a digital connection, an
`ADSL, cable, or wireless modem, and/or quality of service
`and RSVP service systems for managing communications
`via the digital communications connection.
`The above and other objects and advantages of the present
`invention shall be made apparent from the accompanying
`drawings and the description thereof.
`
`BRIEF DESCRIPTION OF THE DRAWING
`
`The accompanying drawings, which are incorporated in
`and constitute a part of this specification, illustrate embodi—
`ments of the invention and, together with a general descrip-
`tion of the invention given above, and the detailed descrip-
`tion of the embodiments given below, serve to explain the
`principles of the invention.
`FIG. 1 is a telephone network architecture in accordance
`with principles of the present invention;
`FIG. 2A is a flow chart illustrating operations of the above
`described equipment in terminating an incoming voice over
`VoIP call from an Internet connection;
`FIG. 2B is a flow chart
`illustrating the process for
`handling an incoming analog/POTS telephone call from the
`publicly switched telephone network directed to an IP tele-
`phone;
`FIG. 2C is a flow chart
`generating outgoing calls.
`
`illustrating the process for
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`DETAILED DESCRIPTION OF SPECIFIC
`EMBODIMENTS
`
`Referring now to FIG. 1, a telephone network architecture
`for combined VoIP, data, and analog POTS telephony in
`accordance with the principles of the present invention can
`be explained. In the combined system 10 illustrated in FIG.
`1, the publicly switched telephone network 12 and Internet
`14 are utilized for telephony originating from the premises
`16 of a subscriber. As can be seen on FIG. 1, the subscriber’s
`premises 16 includes computer systems 17 arranged for
`Internet telephony using, for example, “NetMeeting”, as
`well as dedicated IP telephones 18. These IP telephones and
`computer systems interconnect for Internet telephony Via a
`network connection such as an Ethernet connection 20
`
`connected between each of the computer systems. Ethernet
`connections 20 may be routed through Ethernet switches or
`an Ethernet hub for use of a digital subscriber line (DSL)
`Internet connection. The switches or hub used for network-
`
`ing may be alone devices or alternatively may be incorpo-
`rated within a digital subscriber line modem 22.
`Subscriber premises 16 also includes a call forwarding
`manager 24 utilized in the manner described below to
`facilitate conversion between analog and Internet telephony.
`As will be elaborated below, call forwarding manager 24 is
`a proprietary hardware device for connection to a standard
`analog POTS telephone line such as line 32 illustrated in
`FIG. 1, and connection to an Intemet connection such as via
`Ethernet connection 20 illustrated in FIG. 1. Call forwarding
`manager 24 receives incoming POTS telephone calls as a
`trigger to initiate VoIP telephony. CFM 24 may add value to
`this function by extracting from inbound calls dialed number
`information service (DNIS) data as well as automatic num-
`ber identification (ANI) information. The purpose of call
`forwarding manager 24 is to identify calls, optionally collect
`DNIS and ANI information, and forward this data via the
`DSL or another Internet connection to a call manager so that
`analog calls may be appropriately terminated at a suitable
`voice gateway for subsequent connection to IP telephony
`equipment.
`CFM 24 may also include additional value added features.
`For example, the CFM 24 may incorporate a DSL modem,
`eliminating the need for a separate modem. Other functions
`that might be incorporated include an Ethernet hub or
`switch, firewall or virtual private networking (VPN) func-
`tionality, quality of service (QOS) or RSVP services for
`local area networking, or other administrative functions.
`Furthermore, CFM 24 may be configured as a computer
`peripheral for a computer system such as 17 at the subscrib-
`er’s premises, in which case the digital connections of the
`CFM 24 may be made via a Universal Serial Bus (USB),
`Firewire or other serial connection, or a IEEE-488 parallel
`port connection. CFM 24 could also be constructed as an
`expansion card for a computer system 17, in which case the
`digital connections of the CFM may be made via PCI, ISA
`or other internal bus connections.
`
`Call forwarding manager 24 may include a POTS jack for
`connection to an analog telephone line and an analog
`telephone 23. This would permit POTS telephony to be used
`in unusual circumstances such as ADSL link failures. Alter-
`
`natively, CFM 24 may be configured as a mixed capability
`IP/analog telephone, positioned and used as an IP telephone
`under ordinary circumstances but also available for POTS/
`analog telephony in emergency situations.
`As a further alternative, CFM 24 may operate as a backup
`gateway for the IP telephones, usable in the event that the
`main Internet connection fails. In such a circumstance, the IP
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`to the main
`telephones may be configured, on timeout
`connection, to connect to the CFM 24 so that the CFM 24
`may provide backup gateway services by connection to the
`POTS telephone line. In this embodiment, the subscriber
`may have multiple POTS telephone lines, each coupled to
`the CFM 24, so that CFM 24 may provide multiple lines of
`service as a backup to IP telephony via the Internet connec-
`tion.
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`CFM 24 may also provide connectivity to services other
`than IP telephony. For example, CFM 24 may provide an
`interactive voice response service, or connect to such a
`service, that can provide services such as Intemet-routed
`X10 control of business or household appliances, via a voice
`response system. Other possibilities for voice response
`and/or Internet services may also be made available through
`CFM 24.
`
`As seen on FIG. 1, the subscriber premises 16 utilizes
`only a DSL telephone connection for all telephony and
`Internet communications performed by the subscriber. As is
`known in the art, a digital subscriber line telephone connec-
`tion utilizes frequency band multiplexing; analog POTS
`telephone data is carried at frequencies below 4.0 kHz and
`a digital data modulated at frequencies between 4.0 kHz and
`1.1 MHz. Within the subscriber premises, analog telephone
`connections may be made to the DSL telephone line utilizing
`filters or diplexers (POTS splitters). Such equipment is used
`by CFM 24 to interact only with analog telephone signals on
`line 32. DSL modem 22 incorporates filtering circuitry to
`operate only with DSL telephone line 34 in the upper
`frequency band of 4.0 kHz to 1.1 MHZ, for data commu-
`nications.
`
`A DSL telephone connection 30 is supported by a DSL
`access multiplexor (DSLAM) 40 maintained by the local
`telephone carrier. DSLAM 40 is used by the telephone
`carrier to provide DSL connections to plural subscribers in
`a given geographic area. DSLAM 40 connects to the central
`office switch 42 maintained by the local telephone carrier
`which provides all analog/POTS telephone connection
`switching for all analog/POTS connections to subscribers
`through DSLAM 40. DSLAM 40 is further connected to the
`Internet 14 via a suitable network connection, such as a
`router maintained by the local
`telephone carrier or an
`affiliated Internet access provider.
`DSL access is provided by telephone carriers on the
`assumption that all telephony traffic will continue to be
`routed on analog/POTS service through DSLAM 40 to
`central office switch 42, and from there to the publicly
`switched telephone network 12 via connection 43. In accor-
`dance with the principles of the present invention, a sub-
`scriber may utilize Internet IP telephony in all cases via an
`independent service provider and thereby discontinue use of
`direct analog/POTS telephony via the local carrier central
`office switch 42, except perhaps in emergency conditions.
`This permits the subscriber to access lower cost of service IP
`telephony without any resulting loss of convenience to the
`subscriber.
`
`To facilitate this goal, an independent service provider
`provides a voice gateway 44 and call manager 46 which are
`shared by plural subscribers connected via DSL service to
`local telephone carrier(s). Voice gateway 44 which in one
`embodiment of the invention is a CISCO VG200 available
`
`Cisco Systems, Inc., is connected to the publicly switched
`telephone network 12 via a time division multiplexing
`(TDM) or foreign exchange office (FXO) connection, and
`connected to the local telephone central office switch 42 via
`a similar TDM or FXO connection. Voice gateway 44 is also
`connected to DSLAM 40 via an Ethernet connection directly
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`7
`or indirectly leading to a router to permit the exchange of
`digitized voice packets between voice gateway 44 and
`DSLAM 40.
`
`A call manager 46 is also interconnected to voice gateway
`44, via an Ethernet connection directly or indirectly leading
`to a router permitting call manager 46 to control operations
`of voice gateway 44 using media gateway control protocol
`(MGCP) commands as described in further detail below.
`Optionally, call manager 46 may be connected to central
`office switch 42 using a telephony application programming
`interface (TAPI) connection 45 that may be provided by the
`telephone carrier. Call manager 46 is further connected to an
`Internet connection 14 such an Ethernet connection directly
`or indirectly leading to a router, to permit call manager to
`receive Internet protocol requests and responses from call
`forwarding manager 24, IP telephones 18 and remote call
`manager 46. Call manager 46, in one embodiment of the
`present invention is a CISCO MCS 783x, also available
`from CISCO Systems, Inc.
`The TDM or FXO connections available to voice gateway
`44 permit voice gateway 44 to terminate incoming analog/
`POTS telephone calls and convert those calls for use by IP
`telephones 18. Furthermore, calls originated by IP tele-
`phones 18 that are to be delivered to analog/POTS recipients
`may be converted by voice gateway 44 for delivery via TDM
`to the publicly switched telephone network 12 or the central
`office switch 42. In a wide area implementation of the
`present
`invention, a plurality of call manager 46/voice
`gateway 44 pairs will be positioned at a variety of local
`telephone calling areas. The voice gateway/call manager
`pairs may be grouped at one or more central telephone
`facilities, networked to the local telephone facilities, and/or
`may be located at the facility of an Internet service provider
`and may be interconnected via Internet networking or via
`intranets (which may be proprietary or may be leased from
`communications carriers).
`Referring now to FIG. 2A, operations of the above
`described equipment in terminating an incoming voice over
`VoIP call from an Internet connection can be explained. In
`step 100, the incoming VoIP telephone call is received using
`the H.323 protocol standard. Step 102, the VoIP is tenni-
`nated at the call manager 46. This will occur because the
`destination IP address for any IP telephone owned by a
`subscriber will be directed to the IP address of the call
`
`manager 46, in all name services to which the subscriber
`identified. Upon receiving the call in step 102, in step 104
`the call manager 46 will utilized internal tables to identify
`the subscriber premises 16, and the IP address of the desired
`destination IP telephone at the subscriber premises 16. The
`call manager 46 will then ring the destination IP telephone
`utilizing the H.323 protocol standard. Note that a subscriber
`16 may have multiple IP telephones each assigned its own
`IP address. The use of multiple telephones may be facilitated
`by call manager 46 simply by providing separate IP
`addresses for each desired IP telephone in the routing tables
`at call manager 46.
`When call manager 46 rings the desired IP telephone, it
`will either be busy, answer, or not answer. If busy or no
`answer occurs in step 106, then in step 108 the call manager
`46 may terminate the H.323 connection to the incoming call
`thus ending the IP telephone exchange. Alternatively, call
`manager 46 can provide additional services beyond simply
`routing of telephone connections to IP telephones. For
`example, IP telephone calls received from call manager 46
`may be routed to voice messaging in a no answer or busy
`condition, or may be forwarded to an identified IP or
`analog/POTS telephone in such conditions, for example to a
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`monitoring extension at the subscriber premis