Abstract:
In a communications system, a first packet network is provided. Packetized data is transferred between the system and one or more packet-based devices. A TDM network is provided, and data is transmitted in frames having slots. Data transmitted via the TDM network includes data for voice communications for telephony devices. The TDM network is selectively coupled to the first packet network and a WAN. A processor and a control bus interface circuit control transfer of packetized data and transmittal of data for voice communications. The processor controls processing of packetized data and data&#39;for voice communications. A switch/multiplexer selectively controls providing data to/from particular slots. The processor selectively controls voice communications from telephony devices over the TDM network and packet-based communications over the packet network. Voice communications that stay in a circuit-switched form occur over the TDM network and the WAN.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to systems and methods for transmitting and receiving voice and data in multiple modes, and more particularly to systems and methods for multiple native mode voice and data transmissions and receptions with a communications system having a multi-bus structure, including, for example, a time division multiplexed (“TDM”) bus, a packet bus, and a control bus, and multi-protocol framing engines, preferably including subsystem functions such as PBX, voice mail, file server, web server, communications server, telephony server, LAN hub and data muter. 
       BACKGROUND OF THE INVENTION 
       [0002]    Businesses, particularly small to medium size offices, typically have a need for a variety of voice and data communications. For example, a typical office might have a dedicated fax machine, using a dedicated or shared telephone line, one or more telephone lines for voice communications, perhaps coupled to a central or distributed voice mail system(s), and one or more computers or computer networks, often coupled to telephone lines via one or more modems. Many offices now use the Internet in some form for business communications or research or the like, often by way of a modem or modem pool coupled to individual computers. 
         [0003]    Typically, such business communication needs have been fulfilled with piecemeal technical solutions, typically from separate equipment and service vendors, and with separate hardware, software and design considerations. 
         [0004]      FIG. 1  illustrates a conventional small office communication configuration. Voice communication system  1  typically is implemented by way of multiple analog trunks  16  from wide area network (“WAN”)  18 . WAN  18  often consists of a telecommunication network by way of a local telephone company or other telecommunications service provider. Analog trunks  16  may be directed through switching system  10 , which may be a conventional PBX or similar telephone switch. Telephones  12  and voice mail system  14  are coupled to switching system  10 . Often, dedicated analog line  16 A is coupled to facsimile  44  for facsimile communications. 
         [0005]    Data system  2  typically is implemented with a plurality of computers (or workstations, etc.)  24  interconnected by way of packet network  26 , which may be a standard Ethernet compliant network or other office network. Network  26  often is coupled to remote access server  32 , which is connected to one or more analog trunks  40 , and which may include one or more modems in a modem pool. Computers  24  may communicate with remote systems via the modem pool of remote access server  32  over analog lines  40  and WAN  42 . Network  26  typically includes a connection to printer  22  and file server  20 . In more sophisticated systems, network  26  to may be coupled to switching hub  28  and router  30 , which is coupled to WAN  42  over digital trunks  38 . Data system  2  also may include a connection between one or more of computers  24  to modem  36 , which in term is coupled to WAN  42  over dedicated analog trunk  40 A. 
         [0006]    Such a conventional system often is characterized by piecemeal equipment and network solutions, limited or non-existent coordination and management between voice system  1  and data system  2 , non-optimized or non-integrated equipment, and inefficient use of costly network services (telephone lines, data lines, etc.), such as duplicate and often idle phone and data network lines, often provided from multiple equipment/service providers. In general, such conventional systems are neither constructed nor operated in a manner to provide efficient and integrated voice/data communications. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is intended to address various disadvantages of such conventional communication systems. The present invention provides various systems and methods, perhaps more succinctly a platform, by which voice and data communications may occur in multiple modes and various protocols, and more particularly systems and methods for multiple native mode voice and data transmissions and receptions with a communications/computing system having a multi-bus structure, including, for example, a TDM bus, a packet bus and a control bus, and multi-protocol framing engines, preferably including subsystem functions such as PBX, voice mail and other telephony functions, email and/or file server, Internet server, LAN hub and data router. With the present invention, a platform and various processes are provided in which a TDM bus and a packet bus are intelligently bridged and managed, thereby enabling such multiple mode/protocol voice and data transmissions to be intelligently managed and controlled with a single, integrated system. 
         [0008]    In preferred embodiments, a computer or other processor includes a local area network controller, which provides routing and hubs and/or switches for one or more packet networks. The computer also is coupled to a multiple buffer/framer, which serves to frame/deframe data to/from the computer from TDM bus. The buffer/framer includes a plurality of framer/deframer engines, supporting, for example, ATM and HDLC framing/deframing, and raw buffering of voice data or the like. The buffer/framer is coupled to the TDM bus by way of a multiple port or multiport switch/multiplexer, which includes the capability to intelligently map data traffic between the buffer/framer and the TDM bus to various slots of the TDM frames. Preferably, a DSP pool is coupled to one or more the switch/multiplexer ports and/or the buffer/framer in a manner to provide various signal processing and telecommunications support, such as dial tone generation, DTMF detection and the like. The TDM bus is coupled to a various line/station cards, serving to interface the TDM bus with telephone, facsimiles and other telecommunication devices, and also with a various digital and/or analog WAN network services. The present invention provides a platform by which processing functions may be switched in to provide support for a wide range of network, vendor and application services. 
         [0009]    With the present invention, a full PBX-type telecommunication system may be provided by way of the computer/processor and associated telephony hardware and software. Functions such as voice mail, automated attendant, call forwarding, hold, transfer, caller ID, conferencing and other telephony functions may be similarly provided. While supporting such telephony functions in their native mode primarily by way of the TDM bus, the computer/processor also supports concurrent packet data transmissions over the LAN subsystem and packet bus(es). As needed to efficiently support various voice/data communications in the particular office/work environment, the buffer/framer and switch/multiplexer provide a multi-protocol router functionality, enabling the TDM bus traffic and the packet bus traffic to be intelligently bridged and managed without degradation of each other, and without requiring translation or transcoding. With the present invention, the same WAN services may be intelligently managed and controlled for simultaneous voice, video and data traffic. 
         [0010]    The computer/processor supports a variety of applications, such as remote configuration, management and back-up, bandwidth allocation and control, least cost routing, voice over Internet Protocol (or “voice over IP”), as well various telephony related applications. In certain preferred embodiments, audio/video data streams, including such as H.320 and H.323 data streams, also are intelligently managed and controlled. In certain preferred embodiments, management applications (such as the SNMP protocol) enable the system to be remotely monitored and configured via a web browser-type access. 
         [0011]    Accordingly, it is an object of the present invention to provide simultaneous voice, video and data communications with a single, integrated system. 
         [0012]    It is another object of the present invention to provide an intelligently controlled and managed processor bridge between one or more TDM buses and one or more packet buses. 
         [0013]    It is yet another object of the present invention to provide an integrated PBX, router and hub to support such simultaneous voice, video and data communications. 
         [0014]    It is still another object of the present invention to provide a multi-protocol buffer/framer and switch/multiplexer in order to provide multi-protocol routing and intelligent time slot mapping to the TDM bus, preferably including DSP resources coupled to the buffer/framer. 
         [0015]    Finally, it is an object of the present invention to provide systems and methods allowing a broad set of services and functions to co-exist in the same system, and leveraging shared resources while providing a high level interface and intelligence that allows for the shared resources to be dynamically allocated and re-allocated. 
         [0016]    Other objects, features and advantages of the various embodiments of the present invention described herein will be apparent to those skilled in the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The above objects and other advantages of the present invention will become more apparent by describing in detail the preferred embodiments of the present invention with reference to the attached drawings in which: 
           [0018]      FIG. 1  illustrates a typical, conventional office communications configuration; 
           [0019]      FIG. 2  provides an overview of an office communications system in accordance with preferred embodiments of the present invention; 
           [0020]      FIG. 3  is a block diagram illustrating preferred embodiments of the present invention; 
           [0021]      FIG. 4  provides a software/hardware overview of an office communications system in accordance with preferred embodiments of the present invention; and 
           [0022]      FIG. 5  illustrates the use of services/bandwidth allocation rule table(s) in accordance with preferred embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0023]    Although various preferred embodiments of the present invention will be disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and/or substitutions are possible without departing from the scope and spirit of the present invention. 
         [0024]    In accordance with preferred embodiments of the present invention, systems and methods are provided to enable voice, data, video and other communications to occur in an efficient and integrated manner, intelligently allocating and utilizing available communications resources.  FIG. 2  provides an overview of such a system in accordance with one preferred embodiment of the present invention. 
         [0025]    Communications system  50  provides an integrated system for controlling and managing communications such as in an office. Communications system  50  communicates over ports  26  to file server  20 , printer  22  and one or more computers  24 . Ports  26  typically includes a packet bus such as Ethernet, “fast” Ethernet, ATM or other LAN technology (in other embodiments, LAN technology, such as token ring, may be coupled to an appropriately configured port). Communications system  50  includes devices for controlling ports  26 , including controllers such as what are known as a network interface controller (MC), which may integrate a media access controller (MAC) for control of and interface to ports  26 . Connected to ports  26  may be a variety of devices, such as one or more file servers  20 , computers  24 , printers  24  and other computing, peripheral or similar devices suitable for interconnection with ports  26 . Other network devices, such as routers, switches, bridges and the like also may be connected to ports  26 . In a one preferred embodiment, ports  26  is an Ethernet-type LAN to which is connected to a variety of devices as determined by the needs of the particular office/work environment. The present invention effective integration of the packet data LAN and muter-type functions with the telephony and server functions, which enables unique operations and the initiation or completion of calls or transactions or the like, without having access to traditional, dedicated devices, peripherals and communications services. 
         [0026]    Communications system  50  includes the functionality of what is known as a PBX (as will be described further). In preferred embodiments, communications system  50  is connected to a plurality of telecommunication devices, such as telephones  12 , facsimile  44  and other suitable telecommunications devices and access and server functions (such as private voice mail, recording devices, WAN service interface cards, etc.). What is important is that communications system  50  include interfaces for a plurality of telecommunications devices for the particular and complete office/work environment and infrastructure. 
         [0027]    Communications system  50  is coupled to WAN voice/data services network(s)  58  through trunks  54 . Voice/data services network(s) may include private line, local or long distance carrier networks, Internet, intranet and/or any other current or future WAN-type network services. Trunks  54  may consist of high, medium or low speed digital and/or analog lines, either public or private, and in certain preferred embodiments consist of high speed dedicated resources such as what are known as T-1, PRI (Primary Rate ISDN), ATM, VDSL, HDSL, ADSL, wireless, cascade, proprietary and/or twisted pair analog lines from a local telephone company. What is important is the communications system  50  is coupled to WAN services, trunks and the like in a manner that the user, service provider, administrator and/or algorithm has determined will provide adequate or required resources, on a cost-effective basis, for the particular office/work environment and operating conditions. 
         [0028]    In contrast to  FIG. 1 , the communications system of  FIG. 2  provides an integrated solution for voice and data communication services, to which may be connected the WAN network services and telecommunications, computing and other devices as determined by the particular office/work environment. 
         [0029]    Referring to  FIG. 3 , various subsystems, components, buses and the like of preferred embodiments of communications system  50  will be described in greater detail 
         [0030]    Communications system  50  is controlled by host processor/system resources  70 , which in preferred embodiments include a computer powered, for example, by a commercially available or other microprocessor and an embedded and/or commercially available operating system). What is important is that processor/system resources  70  provide sufficient processing power, memory and storage resources (RAM, ROM, hard disk, magnetic or other storage, etc.), bus and other resources in order to control the various subsystems and components as will be described. IN particular, computer/system resources  70  enables automatic internal negotiation, control and enabling of services and applications. Although not expressly shown, processor/system resources  70  also may include other components of a relatively high-end personal computer, workstation or server, such as a display device, keyboard, serial ports, parallel ports, power supply and the like. The various subsystems and components of communications system  50  are intelligently controlled, managed and monitored by processor/system resources  70 . Processor/system resources  70  provides system and server management software and the like, and a platform for various server applications as described herein. 
         [0031]    Host processor/system resources  70  is coupled to buffer/framer  72  via bus  84 , which in preferred embodiments consists of a computer bus such as what are known as a PCI bus or ISA bus (in other embodiments, other suitable computer-type buses are utilized, which may include proprietary local buses). Buffer/framer  72  includes buffer  71  and preferably includes a plurality of multi-protocol framing/deframing engines, such as for what are known as asynchronous transfer mode (ATM) or high-level data link control (HDLC) protocols, which may be synchronous or asynchronous. In other embodiments, other communication protocol framers/deframers are provided, as may be desired by the particular office/work environment. Buffer/framer  72  in certain preferred embodiments includes, for example, one or more ATM framers/deframers  73 A and one or more, and preferably a plurality of HDLC framers/deframers  73 B. Although not expressly shown, buffer/framer  72  includes other controlling circuits (such as a slot mapping memory, multiplexers/demultiplexers, arbitration, control and other circuitry) such as, for example, described in U.S. Pat. No. 5,533,018 to DeJager, et al for “MULTI-PROTOCOL PACKET FRAMING OVER AN ISOCHRONOUS NETWORK,” which is hereby incorporated by reference. As will be described in greater detail, buffer/framer  72  includes the capability to transfer raw or protocol-processed data, which may be mapped to particular slots of TDM bus  78  and made available on different ports. Buffer/framer  72  is controlled by processor/system resources  70  as diagrammatically indicated by control line(s)  92  (control line(s)  92  may be implemented as part of a bus structure, such as bus  84 ). In preferred embodiments, processor/system resources  70  includes redundant disk or other storage, redundant power supplies and data back-up to magnetic or other media in order to enhance fault tolerance of the system. 
         [0032]    Processor/resources  70  also may be connected to DSP  76 . DSP  76  preferably consists of a single digital signal processor or multi-digital signal processor resource pool, which serves to provide a variety of functions within communications system  50 . In preferred embodiments, DSP  76  generates dial tones (such as for telephones  12 ), DTMF digit detection and decoding, echo cancellation, coding/decoding functions, voice conferencing, voice compression, voice recognition and the like. In other embodiments, DSP  76  performs data compression, transcoding, processing for voice communications using an Internet protocol (“IP”) or the like. In general, DSP  76  provides a set of processing and memory resources to support the various voice/data services controlled and managed by processor/resources  70 . As illustrated by bus connection  84 A, DSP  76  alternatively may be coupled directly to TDM bus  78 . 
         [0033]    Switch/multiplexer  74  communicates bidirectionally with buffer/framer  72  and preferably from DSP  76 , as illustrated, over bus  86 . Switch/multiplexer  74  also communicates with TDM bus  78 , as illustrated, over bus  90 . TDM bus  78  preferably is a time division multiplexed bus as is known in the art (such as, for example, what is known as an MVIP or multi-vendor integration protocol type bus), and provides in certain preferred embodiments  256  channels/slots per TDM frame (the present invention is not limited to a single TDM bus; in alternative embodiments, more than one TDM bus or other types of TDM buses are utilized). TDM bus  78  allows communication between devices on the bus by way of circuit switching techniques. This type of switching allows for simple and inexpensive communication of voice through, for example, what are known as pulse code modulation (“PCM”) techniques. Switch/multiplexer  74  preferably is implemented with one or more switching/serial time division multiplexing circuits, such as, for example, described in U.S. Pat. No. 5,541,921 to Swenson, et al. for “ISOCHRONOUS SERIAL TIME DIVISION MULTIPLEXER,” which is hereby incorporated by reference. Switch/multiplexer  74 , under control of processor/system resources  70 , provides the capability for various voice/data signals to be controllably switched to desired slots of TDM bus  78 . 
         [0034]    Coupled to TDM bus  78  are line, station, trunk, or other interface cards  82 . Cards  82  provide CODEC, line interface, off-hook detect and other functions as are known in the art to support various telecommunication devices (such as telephones  12  and facsimile  44 ) and WAN-type network services (such as voice/data services  58 ) that are communicating with communications system  50  via TDM bus  78 . In preferred embodiments cards  82  provide points of termination for a plurality of telephones  12 , one or more facsimiles  44 , and various T-1, PRI, ATM, analog and/or other WAN-type network services as determined by the particular office/work environment. Cards  92 , under control of processor/system resources  70 , may include points of termination for emergency or backup telephone services and the like, such as in the event of a power failure or to provide analog services in the event a dedicated resource such as a T-1 is unavailable for some reason. 
         [0035]    Communication system  50  also may include fax modem  75 , which, under control of processor/system resources  70 , may process incoming/outgoing facsimile transmissions. In the preferred embodiment, fax modem  75  is coupled to TDM bus  78  as illustrated, although in other embodiments fax modem  75  may be coupled in alternative arrangements, such as to switch/multiplexer  74  and/or DSP  76 . 
         [0036]    Communication system  50  also may include available card slots on TDM bus  78  for one or more module upgrade  77 . Additional resources and/or functionality may be added to communication system  50  as needed by way of module or line card upgrade(s)  77 , or by, for example, the addition of one more cards such as ATM controller  79 B and DSP  79 C. Through the use of such module upgrades or additional cards, etc., one or more minimal configurations of communication system  50  may be provided, with additional resources and/or functionality added by the insertion of additional cards to TDM bus  78 . In accordance with preferred embodiments of the present invention, software upgrades for processor/system resources  70 , or for other resources in the communications system, also may be applied. 
         [0037]    Processor/system resources  70  also is coupled to one or more packet buses, such as packet buses  80 A and  80 B, which may be through a bus such as LAN bus  81 . Effectively, packet buses  80 A and  80 B provide multiple hubs or switches to intercommunicate between one or more packet networks, which in preferred embodiments are Ethernet networks. It should be noted that the bus configuration of  FIG. 3  may be considered “logical”, and in preferred embodiments the physical bus configuration may be such that TDM bus  78  and packet buses  80 A and/or  80 B are part of the same physical bus. In such embodiments, packet buses  80 A and/or  80 B also can intercommunicate directly with central resources (such as processor/system resources  70 ) as well as station cards and WAN cards (or any other cards) coupled to the TDM bus (this is illustrated in  FIG. 3  by card  79 D, which is a card simultaneously inserted into/coupled to both TDM bus  78  and packet bus  80  A and which may comprise, for example, a combined LAN interface/functionality and central office (or other WAN interface) card. Such a combined interface card, which may support both LAN and WAN functions (such as described elsewhere herein), enables substantial advantages over conventional systems. 
         [0038]    Coupled to packet buses  80 A and/or  80 B are a variety of computing-type devices, such as computers  24 , printer  22 , other computers, file servers, backup or storage resources, other networks and the like. Processor/system resources  70 , in software and/or hardware, provides a LAN/network subsystem, which includes muting and other related functions to support data communications to and from packet buses  80 A and/or  80 B and TDM bus  78 , etc., through several paths or methods. 
         [0039]    In preferred embodiments, a more direct connection between packet bus  80 A and/or  80 B may be established by way of embedded muter or bridge  83 . Router/bridge  83  includes a CPU, TCP/IP controller, muter, stack, Ethernet interface or other functionality as may be desired to couple LAN bus  81  to, for example, one or more HDLC controllers  79 A. Through the use of router/bridge  83 , communications between packet buses  80 A and  80 B may be accomplished while consuming minimal resources of processor/system resources  70 . 
         [0040]      FIG. 4  provides a software/hardware overview of an office communications system in accordance with preferred embodiments of the present invention. It should be noted that the preferred embodiment of  FIG. 3 , with appropriate software in processor/system resources  70 , may provide the software/hardware described in connection with  FIG. 4 , as will be appreciated by those skilled in the art. 
         [0041]    At the server applications level, various software applications may be provided for operation in conjunction with the hardware illustrated, for example, in  FIG. 3 . Such software applications may include what are know as least cost routing (“LCR”), best quality of service (“BQOS”) and bandwidth (“B/W”) rules  21 . LCR, BQOS and B/W rules  21  provide tables, information, rules and/or algorithms by which data and voice communications may be allocated and/or controlled with respect to, for example, the various types of voice/data network services that are available to communications system  50 . Such information may include the current cost of utilizing various resources (based on time of date, amount of usage, integrated amount of usage over some period of time, etc.), and also priority rules for the various types of communications provided by communications system  50 . For example, phone calls may be assigned a priority 1, facsimile calls a priority 2, VoIP calls a priority 3, facsimile over IP calls a priority 4, category 1 data communications a priority 5, and other data communications a priority 6. In preferred embodiments, the priority assignments may change by time of day or month, and/or the priority assignments may be different with respect to different network resources and the like. 
         [0042]    Server encryption applications  23  may be provided in order to provide encryption or similar coding or processing of voice/data communications processed by communications system  50 . VoIP gatekeeper  50  may be provided to service and control voice over Internet protocol (“VoIP”) communications. As more specifically described below, various types of VoIP communications may be effectively managed and controlled in accordance with preferred embodiments of the present invention, such as, for example, a determination that acceptable conditions exist on the Internet for such communications. Directory  27  may be provided in order to make various types of directory information available to users of communications system  50 . Directory information provided by directory  50  may include names, telephone extensions, address or other personal or work information regarding persons or departments, etc., serviced by communications system  50 . Directory  27  also may include similar directory type information for persons or departments, etc. in a remote or other locations, such as may be accessed through voice/data services  58 . 
         [0043]    In general, with the present invention other applications  29  may be provided to support various types of communications in accordance with preferred embodiments of the present invention. 
         [0044]    Intelligent/dynamic B/W, service and resource management  31  is provided to effectively and efficiently control and allocate and de-allocate services and communications resources, such as in accordance with LCR, BQOS, B/W rules  21  (e.g., rules to enable lowest cost, highest quality or otherwise desirable management and control of network or other resources, etc.) or other applications  29  or the like. B/W management  31  also receives as inputs information indicating the total number and types of network resources (of voice/data services  58 , for example) that are available to communications system  50 , and their status and availability at any given point in time. B/W management  31  may receive as an input, or may generate internally, information indicating how much of a measured usage resource may be available at a given point in time (for example, “frame relay,” “private virtual channel” or other network services may be provided on the basis of a predetermined amount of data transmission per fixed time period for a fixed price, with additional charges for usage in excess of the predetermined amount, etc.). As more fully described below, based on the currently available and currently utilized services and resources, B/W management  31  may allocate and de-allocate such services and resources in a desired and/or cost efficient manner. 
         [0045]    Services  37 , which may be supported by database storage  35  (which may be provided as a part of processor/system resources  70 ), include data switching services, router services and PBX station service&amp; In general, in accordance with preferred embodiments of the present invention, and utilizing resources such as described in connection with  FIG. 3 , various communication-related services may be advantageously supplied by communications system  50 . 
         [0046]    For example, data switching services may be provided such as by LAN/NDIS/DDI drivers  39  (LAN, NDIS and DDI being exemplary) through hardware modules such as switched Ethernet  45  and hub  47 . Routing services may be provided such as through WAN drivers (specific network services such as PRI and T-1 being exemplary) through hardware modules such as T-1 module(s)  49 , ISDN module(s)  51 , central office-plain old telephone service (CO-POTS) module(s)  53 , V.35 module(s) (it should be understood that various hardware modules may be utilized in accordance with preferred embodiments of the present invention, as desired to implement the various data switching, routing and other communications connections as may be determined by the needs of the particular office/work environment). PBX station services, such as automated attendant, reception, voice mail and the like, may be provided through station manager  43 . Station manager  43  provides hardware for connection to various telecommunications devices, such as phones  12 , facsimile  44 , etc. In general, station manager  43  provides sufficient interface hardware in order to connect to the various devices that may be determined by the needs of the particular office/work environment). 
         [0047]    Referring now to  FIG. 5 , a general flow chart will be described for illustrating the use of services/bandwidth allocation rules in accordance with preferred embodiments of the present invention. 
         [0048]    Server applications, such LCR, BQOS, B/W rules  21 , may be considered to have various rule sets, such voice rules  93 , data rules  95  and dial-up rules  97  (other rule sets may be provided). Communications system  50  monitors inputs (illustrated as monitor input block  91  of  FIG. 5 ), and based on such inputs and the overall service/network resources available, and in accordance with voice rules  93 , data rules  95  and dial-up rules  97 , allocates and de-allocates resources (illustrated as allocate/re-allocate resources block  99  of  FIG. 5 ). 
         [0049]    Exemplary operations of such preferred embodiments will now be described. 
         [0050]    In the event a user picks up one of telephones  12 , an off-hook condition is detected by the appropriate card  82 , which signals processor/system resources  70  of the off-condition. Processor/system resources  70  controls switch/multiplexer  74  to couple the appropriate card  82  to DSP  76 , which generates a dial tone that is coupled to the appropriate telephone  12 . The user hears the dial tone and may then proceed to place the desired call. DSP  76  detects the digits of the telephone number of the desired call and provides the detected digits to processor/system resources  70 . For an internal call, processor/system resources  70  directs that the called internal telephone receive a ring signal from the appropriate card  82 . Upon pick-up of the called internal telephone, the telephone connection between the internal phones is established by way of TDM bus  78  and the appropriate cards  82 . 
         [0051]    For an external call, processor/system resources  70  attempts to establish the desired connection through the appropriate cards  82  and available voice/data services  58 . In attempting to establish such a voice communication connection, processor/system resources preferably follows the general flow illustrated in  FIG. 5 . Namely, in accordance with available resources (such as of voice/date services  58 ) and rules such as voice rules  93 , data rules  95 , dial-up rules  97 , etc., an external voice communication may be established by, for example, a POTS line connection, an ISDN B channel, a VoIP connection, etc. In accordance with the present invention, resources may be allocated for the processing of such an external call based on the available resources at the particular time and applicable rules (which may include time of day, priority of call, etc.) 
         [0052]    Incoming calls are detected by the appropriate cards  82  and signaled to processor/system resources  70 . Connections of voice incoming calls to telephones  12  are established under control of processor/system resources  70  over TDM bus  78 . 
         [0053]    Although various preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and/or substitutions are possible without departing from the scope and spirit of the present invention as disclosed in the claims.