Patent Publication Number: US-7710949-B1

Title: Distributed telecommunication network

Description:
RELATED APPLICATIONS 
   This application is a continuation of U.S. application Ser. No. 09/834,267, filed Apr. 12, 2001 now U.S. Pat. No. 6,904,038 by Billy G. Moon and Roger B. Melton and entitled “Distributed Telecommunication Network”. 

   TECHNICAL FIELD OF THE INVENTION 
   This invention relates to the field of telecommunications, and more particularly to a distributed telecommunication network. 
   BACKGROUND OF THE INVENTION 
   Historically, telecommunications have involved the transmission of voice and fax signals over a network dedicated to telecommunications, such as the public switched telephone network (PSTN) or a private branch exchange (PBX). Similarly, data communications between computers have also historically been transmitted on a dedicated data network, such as a local area network (LAN) or a wide area network (WAN). Currently, telecommunications and data transmissions are being merged into an integrated communication network using technologies such as Voice over Packet (VoP). Since many LANs and WANs transmit computer data using packet protocols, such as the Internet Protocol (IP), VoP uses this existing technology to transmit voice and fax signals by converting these signals into digital data and encapsulating the data for transmission over a packet-based network. This technology may be used to overcome some of the disadvantages associated with long distance telecommunications using the PSTN. 
   SUMMARY OF THE INVENTION 
   According to the present invention, disadvantages and problems associated with previous telecommunication systems and methods have been substantially reduced or eliminated. 
   According to one embodiment of the present invention, a telecommunication device includes a first interface coupled to the public switched telephone network (PSTN) in a first local calling area, a second interface coupled to a packet network, and a third interface coupled to a first plain old telephone system (POTS) telephony device. The device also includes a router that directs telecommunications between the first, second, and third interfaces and a gateway that enables telecommunications between the first POTS telephony device and the packet network. Furthermore, the device includes a processor that receives signaling from the first POTS telephony device indicating a desire to establish telecommunications with a second POTS telephony device coupled to the PSTN in a second local calling area and coupled to the packet network. The processor determines whether the telecommunication device has an appropriate amount of associated credit to use the packet network to establish telecommunications between the first and second POTS telephony devices and, if so, establishes telecommunications between the first and second POTS telephony devices using the packet network such that the first and second POTS telephony devices may communicate without using a long distance network coupling the first and second local calling areas. 
   Particular embodiments of the present invention provide one or more of the following technical advantages. For example, embodiments of the present invention provide long distance telecommunications using packet-based communications without the requirement of a packet telephony service provider (such as an Internet telephony service provider) or any additional costs beyond those of the typical Internet service provider. Furthermore, embodiments of the present invention also provide a mechanism for an efficient and cost-effective transition between the circuit-switched telephony infrastructure of the past and the packet telephony infrastructure of the future. For example, particular embodiments implement a distributed packet telephony system that reduces or eliminates the need for the use of the long distance networks of the PSTN and encourages the transition of the local PSTN to a packet-based infrastructure. Such a system may be implemented using relatively low-cost devices located in user&#39;s homes and businesses. Other important technical advantages are readily apparent to those skilled in the art from the following figures, descriptions and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     To provide a more complete understanding of the present invention and the features and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  illustrates an exemplary communication network in accordance with one embodiment of the present invention; 
       FIG. 2  illustrates an exemplary public switched telephone network point-of-presence (PSTN POP) in accordance with one embodiment of the present invention; 
       FIG. 3  illustrates an exemplary user site profile table in accordance with one embodiment of the present invention; and 
       FIG. 4  illustrates an exemplary method for establishing telecommunications between a user site and an appropriate destination using PSTN POPs in accordance with one embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates an exemplary communication network  10 . In the illustrated embodiment, communication network  10  includes a number of user sites  20  coupled using a wide area network (WAN)  30  and the public switched telephone network (PSTN)  40 . Devices at user sites  20  may communicate using WAN  30  and/or PSTN  40 . Traditionally, WAN  30  has been used for data communications and PSTN  40  has been used for voice, video, fax, and other related communications (“telecommunications”). Accordingly different pricing structures have been established for these different types of communications. However, as technologies have developed to merge telecommunications and data communications, these pricing structures have become outdated. Therefore, embodiments of the present invention leverage the convergence of data communications and telecommunications to establish a novel technique for providing telecommunications using a data communications pricing structure. 
   WAN  30  includes one or more computer data networks that are capable of transmitting data communication signals and telecommunication signals (in the form of data). In particular embodiments, WAN  30  is the Internet or any other appropriate network using Internet Protocol (IP). However, WAN  30  may be any type of network that allows the transmission of data and telecommunication signals. Therefore, although subsequent description will primarily focus on IP communications, it should be understood that other appropriate methods of transmitting telecommunications over a data network, such as a Frame Relay, asynchronous transfer mode (ATM), or other “packet”-based network, are also included within the scope of the present invention. 
   PSTN  40  includes switching stations, central offices, mobile telephone switching offices, pager switching offices, remote terminals, and other related local and long distance telecommunication equipment. For example, central offices (COs)  42  couple plain old telephone system (POTS) telephones  22 ,  44  to other local telephones  22 ,  44  and to remote telephones  22 ,  44  (using a long distance network  46 ). The term “telephone” is used to refer to any appropriate telephony device capable of performing telecommunications. The term “local telephone” may refer to telephones  22 ,  44  that are in the same local calling area and thus may communicate without the use of long distance network  46  and without incurring long distance fees or metered/measured call units. The term “remote telephone” may refer to telephones  22 ,  44  that are not in the same local (or “flat rate”) calling area and thus may communicate using long distance network  46 . 
   Central offices  42  in different local calling areas are coupled using long distance network  46  so as to allow communication between telephones  22 ,  44  in different local calling areas that are coupled to central offices  42 . For example, long distance network  46  may be used for telecommunications between telephones  22 ,  44  in different local access and transport area (LATAs) (typically referred to as inter-LATA communications). Long distance network  46  also includes networks that are used for “non-local” intra-LATA telecommunications (for example, telecommunications that incur charges in addition to the flat rate paid by subscribers for local telephone service). The entity or entities that own the communication links comprising long distance network  46  typically charge a fee for the use of these links. For example, a user of a telephone  22 ,  44  may have an agreement with a long distance carrier to provide long distance services at a particular cost per minute (which may differ based on when a telephone call is made). Furthermore, other pricing schemes may be used (such as the use of metered or measured call units). 
   As described above, WAN  30  and PSTN  40  may enable communications to and from user sites  20 . User sites  20  may include a number of devices to facilitate such communications. For example, user sites  20  may include one or more POTS telephones  22  that may be used for telecommunications. Furthermore, user sites  20  may include a local area network (LAN), such as an Ethernet network, that includes one or more LAN devices  52 , such as computers and LAN telephones (for example, IP telephones). In particular embodiments, LAN  50  uses a communication protocol (such as Ethernet) that supports IP communications with an IP WAN  30 ; however, any other appropriate LAN communication protocols may be used. In particular embodiments, user sites  20  may not include a LAN  20 . In such embodiments, user sites  20  may include one or more stand-alone computing and/or communication devices that may communicate with WAN  30  (for example, a stand-alone computer or a stand-alone IP telephone). 
   User sites  20  further include a PSTN point-of-presence (POP)  60  that may be used to couple POTS telephones  22 , LAN  50  and LAN devices  52  (or similar stand-alone devices), WAN  30 , and PSTN  40 . POP  60  may include a router and/or a switch that directs communications to and from telephones  22  and LAN devices  52  to WAN  30  or PSTN  40  as appropriate. Furthermore, as is described in further detail below, POP  60  facilitates telecommunications between a remote user site  20  and a local central office  42  using WAN  30  such that the remote user site  20  is not charged for use of long distance network  46 . POP  60  may be coupled to WAN  30  through the use an interne service provider (ISP)  32  or similar entity. ISP  32  provides a WAN POP through which devices at user site  20  may gain access to the Internet or other WAN  30 . In particular user sites  20 , POP  60  may be coupled to ISP  32  using PSTN  40  (for example, ISP  32  may be “co-located” in a central office  42 ). Furthermore, in particular user sites  20 , POP  60  or LAN  50  may be directly connected to WAN  30  without the use of an ISP  32 . A user associated with each user site  20  typically pays a fixed monthly fee to ISP  32  for unlimited communications to and from WAN  30 . If POP  60  or LAN  50  is coupled directly to WAN  30 , then the user may pay to lease all or part of the communication links used for such a direct connection. In such cases, the user often pays a fixed monthly or annual fee and/or the user may pay for the amount of bandwidth used. 
   Therefore, different pricing structures are typically used for communications using WAN  30  and long distance network  46 . For example, a user may be charged a relatively low fixed price per month for unlimited access to WAN  30 , but may be charged a fee for every minute that the user communicates using long distance network  46 . These different pricing structures may exist even though WAN  30  and long distance network  46  may share many common communication links. For example, much of long distance network  46  may be leased to ISPs  32  and other entities for data communications since long distance network  46  typically includes communication networks, such as ATM networks, that are capable of carrying IP or other data traffic. 
   IP networks and other packet-based networks transmit data by placing the data (which may include voice, video, and fax telecommunication data) in packets and sending each packet individually to the selected destination. Unlike a circuit-switched network (like PSTN  40 ), dedicated bandwidth is not required for the duration of a packet-based telecommunication transmission using WAN  30 . Instead, each network device communicates packets across the network as they become available for transmission. This disparity in the required bandwidth for packet-based and circuit-switched telecommunications is one reason that these two different types of telecommunications are priced differently. The present invention helps to resolve these inconsistencies by using WAN  30  to communicate long-distance telecommunications. As described below, such telecommunications may be communicated as data and thus be priced as typical data communications over WAN  30 . Therefore, a telephone call or other telecommunication that would typically be communicated using long distance network  46  at a per minute charge may be communicated using WAN  30  for the same fixed monthly fee that is charged for data communications. 
   The technology that allows telecommunications to be transmitted over an IP network (as well as other packet-based networks) may be referred to as Voice over Packet (VoP) (one example of which is Voice over IP). IP telephones and other IP telephony devices  52  have the capability of encapsulating a user&#39;s voice or other media inputs into IP packets so that the inputs may be transmitted over WAN  30  and LANs  50 . IP telephony devices  52  may include telephones, fax machines, computers running telephony software (such as “soft phones” or conferencing applications), H.323-compatible devices, or any other device capable of performing telephony functions in an IP network. 
   For those telephony devices that do not have such capabilities, such as POTS telephones  22 ,  44 , POPs  60  may include one or more gateways that convert analog or digital circuit-switched data transmitted by telephones  22 ,  44  and other PSTN devices to packetized data transmitted by WAN  30 , and vice-versa. For example, if voice data packets are transmitted using WAN  30  to a POTS telephone  44 , POP  60  retrieves the data contained in the incoming packets and converts this digital data to the analog or digital format used by the PSTN trunk that couples POP  60  to central office  42 . Since the digital format for voice transmissions over an IP network is often different than the format used on the digital trunks of PSTN  40 , the gateways provide conversion between these different digital formats, referred to as transcoding. Similarly, if voice data packets are transmitted using WAN  30  to a POTS telephone  22 , POP  60  retrieves the data contained in the incoming packets and converts this digital data to the analog or digital format used by POTS telephones  22 . POP  60  also translates between the VoP call control system and the Signaling System 7 (SS7) protocol or other protocols used in PSTN  40 . 
   In addition to these conversion functions, the POP  60  at each user site  20  serves as a PSTN access point that provides local PSTN access to remotely located user sites  20 . Although only two user sites  20   a  and  20   b  are illustrated, the present invention contemplates any appropriate number of user sites  20  in any number of different geographic locations. For example, every PSTN customer location may potentially serve as a user site  20 . In a particular embodiment, user sites  20   a  and  20   b  are located in different geographic areas such that a PSTN telephone call from a telephone  22  at user site  20   a  to a telephone  22  at user site  20   b  would incur charges for the use of long distance network  46 . In such an embodiment, these long distance charges may be eliminated through the use of POPs  60  and WAN  30 . 
   In operation, a user of a telephone  22  at user site  20  places a call to the telephone number assigned to a telephone  22  at user site  20   b  (or any POTS telephone  44  coupled to central office  42   b  or otherwise located in the same local calling area as user site  22   b ). Since the originating telephone  22  is coupled to POP  60   a , POP  60   a  (the “originating POP”) intercepts the call and determines that the call is directed to a destination telephone located in an area where there is another POP  60  (a “destination POP”). Therefore, originating POP  60   a  directs the telecommunications over WAN  30  to user site  20   b  and makes the necessary conversions to communicate the telecommunications from telephone  22  using WAN  30 , as described above. Destination POP  60   b  receives the telecommunications, makes the necessary conversions, and directs the call to the destination telephone (for example, a telephone  22  at user site  20   b , a telephone  44  coupled to central office  42   b , or any telephone  44  coupled to PSTN  40  in the local calling area of user site  20   b ). Therefore, telecommunications between remote telephones may be completed without the use of long distance network  46 . Exemplary methods for conducting such communications are described in further detail below. 
     FIG. 2  illustrates an exemplary POP  60 . POP  60  includes a number of interfaces  62  for coupling POTS telephones  22  and LAN devices  52  (or stand-alone computing devices  52 ) to WAN  30  and PSTN  40 . For example, interface  62   a  may be used to couple one or more POTS telephones  22  at user site  20  to POP  60 . Interface  62   a  may be a foreign exchange station (FXS) interface or any other appropriate interface to POTS phones  22 . Interface  62   b  may be used to couple POP  60  to PSTN  40 . Interface  62   b  may be a foreign exchange office (FXO) interface or other POTS interface, an ISDN interface or other digital interface, a cellular, satellite, or other wireless interface, and/or any other appropriate interface to PSTN  40 . Interface  62   c  may be used to couple POP  60  to WAN  30  (directly, through an ISP  32 , or in any other appropriate manner). Interface  62   c  may be an analog modem and associated jack for connection to a POTS telephone line coupling POP  60  and ISP  32 , a digital modem such as a digital subscriber line (DSL) or cable modem coupling POP  60  and ISP  32 , or any other appropriate interface for coupling POP  60  to WAN  30 . Interface  62   d  may be used to couple POP  60  to LAN  50  or one or more stand-alone computing devices. Interface  62   d  may include a LAN interface (such as an Ethernet interface) or any other appropriate interface. 
   POP  60  further includes a router  64  that communicates data or telecommunications from one interface  62  to one or more other appropriate interfaces  62 . Although the term “router” is used, any other appropriate component for performing this function may be used, including but not limited to, a switch, hub, bridge, brouter, routing switch, or switching hub. Since router  64  is used to couple devices and networks using different communication techniques, POP  60  also includes gateways  66  that may be used to convert communications from packet-based networks such as WAN  30  and LAN  50  to an appropriate format for communication to PSTN  40  or a POTS telephone  22 . 
   The operation of router  64  and/or gateways  66  may be controlled using a processor  68 . Processor may execute software and access data that is stored in a data storage device  70  associated with POP  60 . Data storage device  70  may include any appropriate component or components for storing information, including but not limited to, random access memory (RAM), read-only memory (ROM), flash memory, magnetic storage devices and associated media, and optical storage devices and associated media. Storage device  70  may include software for establishing and maintaining telecommunications between devices and/or networks coupled to interfaces  62 . Furthermore, storage device  70  may include one or more tables  72  including information that may be used to establish such telecommunications. For example, storage device may be used to store a table  72  that associates a list of numbers that are in the local calling area of each user site  20 . Such a table may be used to direct a telecommunication from one user site  20  to another appropriate user site  20 . 
   The various components of POP  60  may be implemented using any appropriate combination of hardware and/or software at one or more locations. Furthermore, although POP  60  is illustrated as a stand-alone device, software and/or hardware used to implement the components of POP  60  may be included in or added to a computing device, such as a personal computer, associated with a user site  20 . For example, appropriate software and/or hardware may be added to a LAN computer  52  to implement POP  60 . In such a case, processor  68  and/or data storage device  70  may be existing components of the computer  52 . 
   The tasks associated with providing telecommunications using POPs  60  may be divided into two generic functions. The first function is to provide local access to PSTN  40  to remote user sites  20 . This function is typically performed by the components of POPs  60 . The second function is to manage the use of POPs  60  and the establishment of telecommunications using POPs  60 . This second function may be performed by POPs  60 , ISPs  32 , and/or other third parties. For example, the information used to establish and manage local PSTN access using POPs  60  may be stored at POPs  60 . In such embodiments, POPs  60  may be part of a peer-to-peer network and exchange information that allow POPs  60  to perform the management function. In other embodiments, the management function may be performed by a third party, such as an ISP  32  or other appropriate entity. In these embodiments, the information used to establish and manage local PSTN access using POPs  60  may be stored by the third party in one or more locations. It certain circumstances, it may be most efficient for one or more ISPs  32  to provide the management function since ISPs may already provide management functions for user sites  20  and thus have the facilities to store and access user information. Alternatively, the management function may generate a market for third-party facilitators. 
     FIG. 3  illustrates an exemplary user site profile table  100  that may be used to manage telecommunications using POPs  60 . Table  100  may be a table  72  stored at POPs  60  or stored in any other appropriate location, as described above. Furthermore, although illustrated as a single table  100 , the information in table  100  may be stored in one or more tables stored at one or more locations. Table  100  includes information that may be used to choose an appropriate destination POP  60  and to determine limitations that may be placed on telecommunications using the destination POP  60 . The information relating to a particular POP  60  in table  100  may be communicated by the particular POP  60  to each of the other POPs  60  or to one or more central repositories (such as ISPs  32 ) when the particular POP  60  is coupled to the packet network or at any other appropriate time. The devices receiving the information may then add the information to table  100 . 
   Table  100  my include a user identifier (ID)  102  associated with each user site  20 . For example, user ID  102  may include an e-mail address of a user associated with each user site (which may be how an ISP  32  already identifies its users), an assigned user ID, or any other appropriate method of identifying each user site  20 . Table  100  may also (or alternatively) include one or more telephone numbers  104  associated with POTS telephones  22  and/or LAN telephones  52  at each user site  20 . These telephone numbers  104  may be used in addition to or instead of a user ID  102  to identify a user site  20 . One or more of the telephone numbers  104  may have an associated indication  105  identifying the telephone number  104  as being associated with an IP or other packet-based telephone (such as a LAN telephone  52 ). Furthermore, telephone numbers  104  may be used to identify the local calling area of each user site  20 . In particular embodiments, each telephone number  104  is associated with the other numbers that are included in the same local calling area as the user site telephone number  104 . These associated local calling area telephone numbers may be included with each telephone number  104  in table  100  or one or more additional tables may be used to associated each telephone number with the other numbers in the same local calling area. In other embodiments, each local calling area in a country or other appropriate geographic region may be assigned a calling area ID. Each telephone number  104  may be associated with one or more calling area IDs in table  100  or otherwise. Each calling area ID may be associated with the telephone numbers in the calling area in one or more tables. Furthermore, any other appropriate techniques for associating a user site  20  and its POP  60  with one or more telephone numbers in the same local calling area may be used and are included within the scope of the present invention. 
   In addition, table  100  may include one or more network addresses  106  associated with the POP  60  located at each user site  20  (or with components of the POP  60 ). Network addresses  106  may be IP addresses or any other appropriate network addresses. Once an appropriate destination POP  60  has been determined (as described below), network addresses  106  allow an originating POP  60  to communicate with the destination POP  60  using WAN  30 . Table  100  may further include an available access time  108  that indicates an amount of “credit” that a user has for use of other POPs  60 . In particular embodiments, the use of POPs  60  for local PSTN access by users associated with user sites  20  may be based on a “sharing” principle. For example, a user site  20  may be credited a minute for each minute that the POP  60  at the user site  20  is used by other user sites  20  for local PSTN access. Alternatively, a user site  20  may be granted access time or other access privileges based on the amount of time that the user site  20  makes its POP  60  available (even though the POP  60  may not be used continuously while the POP  60  is, available). Any other appropriate technique may be used to allot access privileges to a user site  20 . Furthermore, in particular embodiments, user sites  20  may be provided with unlimited use of other POPs  60  and available access time  108  may not be included in table  100 . 
   Table  100  may also include various restrictions and/or rules regarding the use of the POP  60  associated with each user site  20 . As examples only, table  100  may include access time restrictions  110 , user access restrictions  112 , and dialing rules  114 . Access time restrictions  110  indicate the times when a POP  60  may or may not be used by other user sites  20 . Access time restrictions  110  may be selected by a user associated with a user site  20  or may be generated for any other appropriate purpose. User access restrictions  112  may be used to identify particular users or user sites  20  that may or may not use the services of the POP  60  at a user site  20 . Restrictions  110  may be used to limit access to known users or to prevent access by specific users. Restrictions  110  may also be used to limit access to particular groups or types of users (such as in-state or out-of-state user sites  20 ) for regulatory or legal reasons or for any other appropriate reason. Dialing rules  114  may be included in table  100  to indicate particular digits that should be prepended, appended, or otherwise added to or removed from a telephone number when placing a call to that telephone number using a particular POP  60 . For example, a “9” may have to be dialed from a user site  20  to gain access to PSTN  40 . Furthermore, an area code may be required in certain areas (typically large metropolitan areas) to make a local call. Any other appropriate dialing rules  114  may be included in table  110 . 
   Although particular information is described as being included in table  100 , table  100  or other related tables may include any other appropriate information for managing and establishing telecommunications over WAN  30  using POPs  60 . Furthermore, the information included in table  100  or related tables may be expressed in any appropriate format. 
     FIG. 4  illustrates an exemplary method for establishing telecommunications between a user site  20  and an appropriate destination using POPs  60 . The method begins at step  200  where a user initiates a telecommunication, such as a telephone call (including audio and/or video) or a fax, from a telephone associated with an originating user site  20 , such as user site  20   a . The telecommunication may be initiated using a telephone located at user site  20   a , such as a POTS telephone  22  or an IP telephone  52 , or any other telephone that has permission to originate calls from user site  20   a . Such telephones may include telephones not included in a user site  20 , such as a POTS telephone  44  or a cellular telephone. These external telephones may be associated with a user site  20  (for example, the cellular telephone may belong to a user of the user site  20 ) and may call into POP  60  at the user site  20  to initiate a communication with a remote POP  60 . At step  202 , POP  60   a  at user site  20   a  intercepts the signaling from the originating telephone used to initiate the telecommunication. For example, POP  60   a  may intercept dual tone multi-frequency (DTMF) tones communicated from the originating telephone and identifying a destination telephone. If the originating telephone is not directly coupled to POP  60   a , then any appropriate communication techniques may be used to communicate with POP  60   a  and to indicate to POP  60   a  the destination of the desired telecommunication. For example, a user associated with user site  20   a  may call into POP  60   a  from a cellular telephone or POTS telephone  44  and provide signaling information once connected to POP  60   a  to indicate the desired destination. 
   Signaling or other communications from a POTS telephone  22  (received using interface  62   a ) or from a POTS telephone  44  or other telephone coupled to PSTN (received using interface  62   b ) may be manipulated by gateway  66   a  or  66   b , respectively. This manipulation, as described above, may performed to convert the POTS or other communications from telephones  22 ,  44  to a format that may be processed by processor  68  and/or routed by router  64 . For example, analog DTMF tones from a telephone  22  may be converted to digital signals for processing by processor  68 . Any other appropriate conversions or other manipulations may also be performed. 
   At step  204 , POP  60   a  evaluates the initiation signaling from the originating telephone to identify the destination telephone and its location. In particular embodiments, POP  60   a  may evaluate DTMF tones or other received signaling information to determine a telephone number of the destination telephone. Based on the telephone number or other identifying information POP  60   a  may determine the location of the destination telephone. For example, one or more telephone number tables stored at or accessible by POP  60   a  may identify the local calling area with which every telephone number is associated (or this information may be included in table  100 ). Alternatively, a telephone number table may identify the telephone numbers associated with the local calling area in which POP  60   a  is located. 
   At step  206 , POP  60   a  determines whether the destination telephone is located in the same calling area as POP  60   a . If so, POP  60   a  determines whether the connection to the local central office  42   a  (using interface  62   b ) is available at step  207 . If the connection is unavailable, the method proceeds to step  210  (which is described below). If the connection is available, POP  60   a  establishes telecommunications between the originating telephone and the destination telephone using PSTN  40  at step  208 . PSTN  40  is used since there is typically no additional charge for placing a call to a telephone in the same local calling area. Once POP  60   a  determines that PSTN  40  is to be used, POP  60   a  may simply pass telecommunications between the originating and destination telephones without manipulating the telecommunications using gateways  66 . For example, gateway  66   a  may pass telecommunications without alteration between a telephone  22  coupled to interface  62   a  and central office  42   a  coupled to interface  62   b . Alternatively, POP  60   a  may use gateways  66   a  and/or  66   b  to convert between analog telecommunications used by telephone  22  and digital communications used by central office  42  or to make any other appropriate conversions or manipulations. When the telecommunication is finished, the method ends. 
   If POP  60   a  determines at step  206  that the destination telephone is not located in the same calling area as POP  60   a  (or if the PSTN connection is unavailable, as described above), POP  60   a  may then access and evaluate user site profiles in a user site profile table  100  or other location at step  210 . Alternatively, POP  60   a  may communicate information regarding the desired telecommunication to ISP  32  or any other third party and the ISP  32  or third party may manage the establishment of telecommunications using POPs  60 . For the purposes of the following description, it will be assumed that user site profile information is stored at POPs  60  and that POPs  60  manage the establishment of telecommunications. However, it should be understood that one or more of the functions described below may be performed by appropriate components associated with an ISP  32  or other third party. Furthermore, POPs  60  or other appropriate components may access and evaluate user profile information at any appropriate time and not necessarily at (or only at) the exemplary step  210 . 
   Based on the user profile information (such as indications  105  identifying that the destination telephone number is associated with an IP or other packet-based telephone) or based on any other appropriate information (including information in the signaling from the originating telephone), POP  60   a  determines at step  212  whether the destination telephone is a packet-based telephone. If so, POP  60   a  establishes telecommunications between the originating telephone and the destination telephone using WAN  30  at step  214 . Since the destination telephone is a packet-based telephone, there is no need to use a remote POP  60  for local access to the PSTN in the local calling area where the destination telephone is located. If the destination telephone is coupled to WAN  30  through a remote POP  60 , then the remote POP  60  may be used to route the telecommunications to the packet-based telephone (and the network address of the remote POP may be included in user profile table  100 ). For example, the destination telephone may be an IP telephone  52  coupled to WAN  30  using POP  60   b . If POP  60   b  is used in this situation, the originating user site  20   a  may not be charged “credits” for this telecommunication since POP  60   b  is not being used for local PSTN access. Alternatively, such an IP telephone  52  may be coupled to WAN  30  without using POP  60   b  (for example, IP telephone  52  may be coupled to a LAN  50  that is coupled to WAN  30 ). 
   POP  60   a  may be used to provide appropriate call set-up and gateway functions. For the purposes of example, it is assumed that the originating telephone is a POTS telephone  22  coupled to interface  62   a  of POP  60   a  and the destination telephone is an IP telephone  52  coupled to interface  62   c  of POP  60   b  using LAN  50 . POP  60   a  may determine whether the IP telephone  52  is available and, if so, set up the telecommunication by instructing gateway  66   a  to set up an audio stream with IP telephone  52  using WAN  30 . The telecommunication may be established and maintained using H.323 (and its related protocols) or using any other appropriate protocols. Telecommunications received from POTS telephone  22  are then digitized (using a codec and/or other appropriate components) and encapsulated for transmission using WAN  30 . The encapsulation may be performed by Real-Time Transport Protocol (RTP) running over UDP (User Datagram Protocol) or using any other appropriate protocols. The UDP packets are then communicated to router  64  which direct the packets to WAN  30  for communication to IP telephone  52  (possibly via POP  60   b ). A gateway  66  of POP  60   b  does not need to be used since the destination telephone is a packet-based telephone. The operation of VoP telecommunications is well known in the art and will not be described in further detail. When the telecommunication between the originating telephone and the destination packet-based telephone is completed, the method ends. 
   If POP  60   a  determines at step  212  that the destination telephone is not a packet-based telephone, POP  60   a  determines at step  216  if the destination telephone is located at a remote user site  20  (for example, a POTS telephone  22  at user site  20   b ). If so, POP  60   a  establishes telecommunications between the originating telephone and the destination telephone using WAN  30  and the remote POP  60 . Such telecommunications may be established in a similar manner as described above with reference to step  214 . However, gateway  66   a  of the remote POP  60  is typically used to communicate the packet telecommunications to a non-packet telephone at the remote user site. 
   For example, if the originating telephone is a POTS telephone  22  at user site  20   a  and the destination telephone is a POTS telephone  22  at user site  20   b , gateway  66   a  of POP  60   a  may receive analog telecommunications from originating telephone  22  and convert the telecommunications for communication using WAN  30 . Gateway  66   a  of POP  60   b  may then receive the packet telecommunications and convert the telecommunications as appropriate for destination telephone  22  at user site  20   b . This process is performed in reverse for telecommunications from destination telephone  22  to originating telephone  22 . As with telecommunications to a packet-based telephone, a user associated with a user site  20  may not be charged credits for telecommunications to a POTS telephone  22  or other non-packet telephone associated with a remote user site  20  since the remote POP  60  is not being used for local PSTN access. 
   If POP  60   a  determines at step  216  that the destination telephone is not located at a remote user site  20 , POP  60   a  determines at step  220  whether the destination telephone is located in the same local calling area as a remote user site  20 . POP  60   a  may make such a determination using the information included in user profile table  100  or other any other appropriate information identifying the local calling areas of one or more user sites  20 . For example, POPs  60  may subscribe to a “subject group” associated with a particular local calling area and POP  60   a  may determine if there is a subject group associated with the local calling area of the destination telephone. If POP  60   a  determines that there are no user sites  20  in the local calling area of the destination telephone, then the exemplary method ends. Alternatively, system  10  may be configured to determine a remote POP  60  that may be used to access PSTN  40  in a different local calling area than the destination telephone, but in a local calling area from which telecommunications with the destination telephone are less expensive than from the local calling area of the originating telephone. 
   If POP  60   a  determines at step  220  that there are one or more user sites  20  in the local calling area of the destination telephone, POP  60   a  determines at step  222  whether the user associated with POP  60   a  has available credit to establish a telecommunication with the remote user site  20 . As described above, this information may be included in user profile table  100 . If the user does not have an appropriate amount of credit, the method ends. If the user has an appropriate amount of credit, POP  60   a  determines an appropriate destination user site  20  through which local PSTN access may be obtained at step  224 . For example, POP  60   a  may search a list of user sites  20  in the local calling area of the destination telephone to determine a user site  20  that allows the user associated with user site  20   a  to establish a telecommunication at the particular time (for example, by evaluating access time restrictions  110 , user access restrictions  112 , and/or any other appropriate criteria). When an appropriate destination user site  20  is identified, POP  60   a  communicates with the POP  60  associated with the user site  20 , such as POP  60   b  of user site  20   b , at step  226  to determine if user site  20   b  is available. For example, POP  60   b  may only be able to establish a single connection to PSTN  40 . Therefore, POP  60   a  may determine if another POP  60  or other component is already using POP  60   b  for local PSTN access. 
   If POP  60   b  is unavailable for this or any other appropriate reason, POP  60   a  determines an alternative appropriate user site  20  at step  228  and the method returns to step  226 . If no there are no alternative user sites  20 , the exemplary method ends. Alternatively, as described above with reference to step  220 , user sites  20  in non-local calling areas may be used. If POP  60   a  determines at step  226  that an appropriate destination user site  20 , such as user site  20   b , is available, POP  60   a  establishes telecommunications with the destination POP  60   b  at step  230 . For example, POP  60   a  may indicate to POP  60   b  the destination telephone number to which telecommunications from POP  60   a  are to be communicated and establish audio streaming between POPs  60   a  and  60   b.    
   POP  60   b  establishes telecommunications with the destination telephone at step  232 . For example, gateway  66   b  of POP  60   b  may communicate the destination telephone number to central office  42   b  and establish a circuit-switched telecommunications channel between gateway  66   b  and the destination telephone, for example a POTS telephone  44 . Telecommunications received at POP  60   b  from POP  60   a  (telecommunications from a telephone  22  or other telephone associated with user site  20   a ) are routed to gateway  66   b  of POP  60   b . Gateway  66   b  performs any appropriate conversions and forwards the telecommunications to the destination telephone  44 . Similarly, telecommunications from the destination telephone  44  are communicated to gateway  66   b  of POP  60   b , converted by gateway  66   b  and communicated to gateway  66   a  of POP  60   a  using WAN  30 , and converted by gateway  66   a  and communicated to the originating telephone  22 . Alternatively, if the originating telephone is an IP telephone  52  at user site  20   a , then the packet telecommunications from gateway  66   b  of POP  60   b  may be communicated directly from POP  60   a  to IP telephone  52 . Furthermore, if the originating telephone is a telephone associated with user site  20   a  but coupled to PSTN  40  (such as a telephone  44  coupled to central office  42   a ), then the packet telecommunications from gateway  66   b  of POP  60   b  may be communicated to and converted by gateway  62   b  of POP  60   a  and then communicated to the destination telephone using PSTN  40 . When the telecommunication between the originating telephone and the destination telephone is completed, the method ends. 
   Although an exemplary method is illustrated and described, the present invention contemplates using any suitable techniques and components for providing local PSTN access through the use of POPs  60 . Moreover, many of the steps in this flowchart may take place simultaneously and/or in different orders than as shown. In addition, the present invention contemplates using methods with additional steps, fewer steps, or different steps. Furthermore, although the present invention has been described with several embodiments, numerous changes, substitutions, variations, alterations, and modifications may be suggested to one skilled in the art, and it is intended that the invention encompass all such changes, substitutions, variations, alterations, and modifications as fall within the spirit and scope of the appended claims.