WO2001067804A2

WO2001067804A2 - Architecture for an access device

Info

Publication number: WO2001067804A2
Application number: PCT/IB2001/000469
Authority: WO
Inventors: Yossef Saad
Original assignee: Adc Telecommunications, Israel Ltd.
Priority date: 2000-03-07
Filing date: 2001-03-07
Publication date: 2001-09-13
Also published as: WO2001067804A3; AU3949701A

Abstract

A method for configuring a service type for an access device in a communication system is provided. The method includes receiving a request for service (402) with a selected service type. The method further includes downloading an application program (412) for the selected service type to a digital signal processor memory at the access device. The method further defines the service (414) for the access device and activates the application on the digital signal processor (416) to provide service with the selected service type.

Description

ARCHITECTURE FOR AN ACCESS DEVICE

TECHNICAL FIELD

The present invention relates generally to the field of telecommunications and, in particular, to an architecture for an access device.

BACKGROUND

Telecommunication networks selectively route signals between subscriber equipment, e.g., telephones, computers, and the like, that are situated at remote locations. Telecommunication networks route signals between subscriber equipment using electronic switches. The switches are located at central offices and are interconnected via communication trunks.

Subscriber equipment communicates with the switches using a mechanism referred to colloquially as the "local loop" or "last mile." Conventionally, this local loop includes, at a minimum, an access device and a pair of copper wires. The access device is located either at the central office or at a remote location.

An access device typically includes a number of line cards. The line cards provide the electronics necessary to process signals between the switch and the subscriber's equipment. Conventionally, the line cards are designed to support one of a variety of services to which a user can subscribe. For example, some line cards are designed to support only Plain Old Fashioned Telephone Service (POTS). Other line cards are designed to support more advanced services such as Integrated Service Digital Network (ISDN) service, Asymmetric Digital Subscriber Line (ADSL) service. One problem with these access devices relates to configuration of the access device to provide services once a line card is installed. Conventionally, a technician configures an access device. The technician travels to the location of the access device and replaces an existing line card with a new line card to change a subscriber's service type, or alternatively reconnects the subscriber's copper pair to a port of a different line card of the new service type. This is time consuming resulting in increased expenses and delays in providing desired service.

For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for an improved architecture for an access device that reduces the drawbacks experienced in changing the service type for a subscriber line.

SUMMARY

The above mentioned problems with line cards and other problems are addressed by embodiments of the present invention and will be understood by reading and studying the following specification. Embodiments of the present invention provide an access device architecture that is programmably configurable. The access device includes two main card types: a generic line card that provides analog front end services applicable across service types and a digital processing card that is configurable with an application program specific to a selected service type. The two cards work in combination to provide a selected service type. By allowing the digital processing card to be programmably configurable, the service type of a specific port can be changed without requiring a teclmician to travel to the location of the access device.

More particularly, in one embodiment a method for programmably configuring a service type for an access device in a communication system is provided. The method includes receiving a request for service with a selected service type. The method further includes downloading an application program for the selected service type to a digital signal processor memory at the access device. The method further defines the service for the access device and activates the application on the digital signal processor to provide service with the selected service type.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of an embodiment of a telecommunications network that provides for programmable configuration of access devices according to the teachings of the present invention. Figure 2 is a block diagram of an embodiment of a generic line card for performing analog termination for a plurality of service types according to the teachings of the present invention. Figure 3 is a block diagram of an embodiment of a digital processing card that is programmable to process signals according to a selected service type according to the teachings of the present invention.

Figure 4 is a flow chart of an embodiment of a process for programmably configuring the service type of an access device according to the teachings of the present invention.

DETAILED DESCRIPTION

In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific illustrative embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that logical, mechanical and electrical changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense.

Figure 1 is a block diagram of an embodiment of a telecommunications network, indicated generally at 100, that provides for programmable configuration of access devices such as access device 102 according to the teachings of the present invention. Access device 102 provides access for subscriber equipment to network(s) 108 via transport equipment 110. Network(s) 108 represents one or more of the Public Switched Telephone Network (PSTN), a packet network, an ATM network, the Internet, or other appropriate networks. It is noted that access device 102 may be located at a central office or at a remote location, e.g., as part of a digital loop carrier circuit.

Advantageously, access device 102 divides the functionality of a conventional line card between two types of modules to allow programmable configuration of the service type for ports of access device 102. The two types of modules are generic line cards (GLC) 104-1, . . ., 104-N and digital processing cards (DPC) 106-1, . . ., 106-M. Each of these two types of modules is described in turn below. Further, Figures 2 and 3 provide specific examples of embodiments of generic line cards and digital processing cards. The first of the two types of modules is represented by generic line cards

104-1, . . ., 104-N. Generic line cards 104-1, . . ., 104-N provide an analog interface for subscriber lines 116 and a digital interface bus 118. Generic line cards 104-1, . .

., 104-N perform analog line termination functions for a plurality of ports. Generic line cards 104-1, . . ., 104-N include basic telephony signaling circuitry, e.g., ringer, battery feed and the like, and analog to digital (A/D) and digital to analog (D/A) converters. The "raw data" samples produced by generic line cards 104-1, . . ., 104-

N carry any appropriate service as defined below, depending of the processing performed on them as described herein. In one embodiment, each of generic line cards 104-1, . . ., 104-N provides from 32 to 64 analog interfaces or ports. In other embodiments, each generic line card provides any appropriate number of ports. A high density of ports on a generic line card is achieved due to the limited functionality of generic line cards 104-1, . . ., 104-N.

The second of the two types of cards is represented by digital processing cards 106-1, . . ., 106-M. Digital processing cards 106-1, . . ., 106-M each include a plurality of programmable, general purpose digital signal processing (DSP) circuits. Each DSP circuit is configurable to implement a service specific algorithm for a selected port of one of generic line cards 104-1, . . ., 104-N. For example, a selected DSP circuit is loaded with one or more application program(s) for specific service(s) such as those identified in Table 1.

Table 1

Since the DSP circuits of digital processing cards 106-1, . . ., 106-M are programmable, it is possible to configure the service type for a port of one of generic line cards 104-1, . . ., 104-N remotely by downloading an application program containing code for the specific service type desired into a memory associated with a selected DSP circuit a d associating the selected DSP circuit with the port of the generic line card. Thus, two modules, one of generic line cards 104-1, . . ., 104-N and one of digital processing cards 106-1, . . ., 106-M, combine to function as a remotely configurable line card. Access device 102 does not require a one to one correspondence between generic line cards 104-1, . . ., 104-N and digital processing cards 106-1, . . ., 106-M. In fact, the ports of a given generic line card 104-1, . . ., 104-N can be serviced by processors on any combination of the digital processing cards 106-1, . . ., 106-M.

Access device 102 also includes first and second buses 118 and 120. In one embodiment, first bus 118 comprises a time division multiplexed bus and second bus 120 comprises a packet bus. First bus 118 provides selective communication of digitized signals between digital processing cards 106-1, . . ., 106-M and generic line cards 104-1, . . ., 104-N.

Access device 102 also includes network transport cards (NTC) 122 and 124 and common equipment 132. The first bus 118 or the second bus 120 provides communication between digital processing cards 106-1, . . ., 106-M and network transport cards 122 and 124. In one embodiment the network transport cards 122 and 124 include circuitry to communicate packetized data with a remote head end, while in another embodiment the network transport cards 122 and 124 include circuitry to communicate TDM data with a remote head end. For example, network transport cards 122 and 124 each include transport interfaces (I/F) 126, timing circuits 128, and TDM/packet MUX/router 130. The transport interfaces 126 comprise at least one of an optical-based, a copper-based or a radio based interface. In different embodiments, the various blocks comprising network transport cards 122 and 124 may be incorporated in a single card or divided into several separate cards. At the head end, packets from transport cards 122 and 124 are relayed to various service nodes of network(s) 108. For example, voice data is provided to TDM switches through a N5.2/GR303 interface, voice over IP data is provided to a router using H.323/MGCP, and IP data is provide to an appropriate network through an IP/ATM interface.

Common equipment 132 is coupled to first and second busses 118 and 120 to provide common services for the various modules of access device 102. For example, common equipment 132 includes circuitry for performing shelf controller functions, alarm interfaces and other appropriate functions. In other embodiments, common equipment 126 is omitted and the functionality is implemented in network transport cards 122 and 124.

On the subscriber side, subscriber equipment 112 is coupled to generic line cards 104-1, . . ., 104-Ν over subscriber lines 116. Each of subscriber equipment 112 comprise one or more of a telephone, computer, fax machine, ISDN telephone, video conferencing equipment, ADSL modem, or other appropriate subscriber equipment for using a selected service type over a selected one of subscriber lines In operation, access device 102 provides communication between subscriber equipment 112 and network(s) 108. Access device 102 allows the service type of the ports of generic line cards 104-1, . . ., 104-N to be configured and modified by selectively loading application programs into memories associated with selected DSPs of digital processing cards 106-1, . . ., 106-M. Essentially, when a port of access device 102 is to be configured, e.g., a port of generic line card 104-1, one of digital processing cards 106-1, . . ., 106-M, with available processing capacity is identified, e.g., 106-M. If an application program for the selected service type for the port is available at access device 102, then the application program is downloaded to a memory associated with the selected DSP of digital processing card 106-M. If the application program is not available, then the application program is downloaded to access device 102 from a remote head end and placed in the memory of the selected DSP. Access device 102 associates the port of generic line card 104- 1 with a selected DSP of digital processing card 106-M and the port is configured for use. Advantageously, this process allows the service type of a port to be programmably configured since the only change from one service type to another is an application program download and activation.

Further, digital processing cards are not dedicated to a specific subscriber and, instead, are a shared resource among generic line cards 104-1, . . ., 104-N. This allows a cost reduction by allowing fewer digital processing cards 106-1, . . ., 106-M to be included in access device 102 when concentration is used. For example, in an access device that supports 300 POTS subscribers, digital processing cards for only 60 simultaneous calls may be sufficient. Additionally, when only simple, low-cost services are required (e.g. POTS services) only one or two DPC cards may be sufficient to support a larger number of generic line cards. Only when more complicated and more expensive services are added (e.g. ADSL), additional DPC cards should be added. This way the investment in equipment is related to the service complexity and potential revenues.

Common equipment 132 also includes monitoring software that advantageously alerts an operator when additional processing is needed at access device 102. If additional processing power is needed, the processing power can be easily added by installing additional digital processing cards as needed. Since the processing cards are not dedicated to a particular subscriber, this monitoring of the processing power is performed on a "shelf or access device level not on an individual subscriber level. Thus, site visits to upgrade access device 102 will be less frequent than conventional access devices. Access device 102 also improves on the ability to quickly and easily add new services. Access device 102 implements new services by a software download to the appropriate digital processing cards 106-1, . . ., 106-M. Finally, access device 102 allows an IP only access system to be easily implemented by an appropriate software download to digital processing cards 106-1, . . ., 106-M. Figure 2 is a block diagram of an embodiment of a generic line card, indicated generally at 200, for performing analog termination for a plurality of service types according to the teachings of the present invention. Generic line card 200 is used, for example, in an access device such as access device 102 of Figure 1 to provide analog line termination. Generic line card 200 includes analog front end modules 202-1, . . ., 202-N.

Analog front end module 202-1 is representative of the analog front end modules and is described in further detail. However, it is understood that the remainder of analog front end modules 202-2, . . ., 202-N are constructed and operate in a similar manner. Analog front end module 202-1 includes line interface (I/F) 206 and wideband analog to digital and digital to analog (A/D/A) converter 208. Line I/F 206 is coupled to a two wire subscriber line and provides a port for generic line card 200. Further, line I/F 206 is coupled to wideband A/D/A 208. Wideband A/D/A 208 is further coupled to TDM bus interface (I/F) 204. TDM bus I/F provides a connection for generic line card 200 to TDM bus 210.

Generic line card 200 also includes card controller 212 and power module 214. Card controller 212 is coupled to control bus 211. Card controller 212 provides signals to analog front end circuits 202-1, . . ., 202-N and to TDM bus I/F 204 to control communication between analog front end modules 202-1, . . ., 202-N and associated digital signal processors of digital processing cards. Card Controller 212 communicates over the control bus 211 with the digital processing cards, the network transport cards and the common equipment. Control bus 211 is identified as a separate entity in Figure 2 for clarity but, in some embodiments, control bus 211 is integrated within either TDM bus 210 or packet bus 213. Power module 214 provides DC feed for subscriber lines as well as other signaling functions such as ringer and the like. In operation, generic line card 200 provides analog termination for a plurality of ports in an access device. In the upstream direction, signals are received at a port of, for example, analog front end module 202-1. These signals are received at line interface 206 and provided as analog signals to wideband A/D/A converter 208. The signals are converted to digital samples and provided to TDM bus 210 by TDM bus I/F 204 for communication to an associated digital signal processor to complete the processing of the signals by the access device.

In the downstream, TDM bus I/F 204 receives digital signals from TDM bus 210 from a digital signal processor for communication to a selected subscriber. TDM bus I/F 204 provides the digital signals to a selected analog front end module, e.g., analog front end module 202-1. At analog front end module 202-1 , the signals are converted to analog form by wideband A/D/A converter 208. Line interface module 206 further provides the analog signal to the subscriber lines.

Figure 3 is a block diagram of an embodiment of a digital processing card, indicated generally at 300, that is programmable to process signals according to a selected service type according to the teachings of the present invention. Digital processing card 300 includes a plurality of digital signal processors 302-1, . . . , 302- M that are assignable to process signals for ports of associated generic line cards. Each digital signal processor is coupled to first and second bus interface (I/F) modules 304 and 306. Bus I/F module 304 provides an interface to TDM bus 308 for providing communication between digital processing card 300, its associated generic line cards and the network transport cards. Bus I/F module 306 provides an interface to packet bus 310 for communication between digital processing card 300 and network transport cards.

Digital processing card 300 further includes memory 312. Memory 312 is associated with digital signal processors 302-1, . . ., 302-M. In one embodiment, memory 312 is a shared memory that is associated with all of the digital signal processors 302-1, . . ., 302-M. In another embodiment, memory 312 comprises a plurality of memory circuits, each associated with one of the digital signal processors

302-1, . . ., 302-M. In another embodiment, memory 312 comprises a plurality of memory circuits that are each fabricated on the same substrate with digital signal processors 302-1, . . ., 302-M. Digital processing card 300 further includes controller 314 and power supply

316. Power supply 316 provides power to the various components and modules of digital processing card 300. Controller 314 communicates over control bus 318 with the other digital processing cards, the network transport cards and the common equipment. Control bus 318 is identified as a separate entity for clarity but, in some embodiments, control bus 318 is integrated within either TDM bus 308 or packet bus

310. Controller 314 provides signals to make associations between digital signal processors 302-1, . . ., 302-M of digital processing card 300 and ports of the generic line cards.

In operation, digital processing card 300 provides processing of digital signals to implement a selected service type for a port of a generic line card. For example, digital signal processor 302-1 runs an application program stored in memory 312 to process signals for POTS service for an associated port of a generic line card. In this example, the memory is loaded with an application program that implements an A-law/μ-law codec. Controller 314 provides the link between digital processing card 300 and the port of the associated generic line card by signals over control bus 318.

In the upstream, digital signals are received from the port over TDM bus 308 and processed by digital signal processor 302-1 according to the code in memory 312. The processed data is provided in one embodiment to packet bus interface 306 and packet bus 310 for transmission to the packet network and in another embodiment to TDM bus interface 304 and TDM bus 308 for transmission to the TDM network.

In the downstream, digital signals are received from the network on TDM bus 308 or packet bus 310. These signals are routed to digital signal processor 302- 1. Digital signal processor 302-1 processes the signals and provides the outgoing data samples to the generic line card over TDM bus 308 through bus I/F 304.

Figure 4 is a flow chart of an embodiment of a process for configuring the service type of a digital processing card according to the teachings of the present invention. The method begins at block 400. At block 402, the method accepts a customer request for a selected service type. At block 404, the method determines whether there are sufficient digital signal processing (DSP) resources available to handle the service type. If not, the method proceeds to block 406 and additional digital signal processing resources are added to the selected access device. When sufficient digital signal processing resources are available, the method proceeds to block 408. At block 408, the method determines whether an application program exists on the access device for the requested service. If not, the application program is downloaded to the access device from the head end. When the application program exists on the access device, the method proceeds to block 412 and downloads the application program to a memory associated with the digital signal processor, and the GLC port that is connected to the specific subscriber is configured to support the service. It is understood, however, that more than one application program may be downloaded and used to provide a selected service type. For example, when POTS and ADSL are to be implemented on the same line, application programs are downloaded for POTS service, ADSL service and a digital splitter. At block 414, the new service is defined at the service node, e.g.,for POTS/ISDN service the new subscriber is defined in voice switch and in the GR- 303/N5 interface. At block 416, the application loaded on the digital signal processor is activated.

With the exception of block 406, the above processes can be performed manually, state by state, or can be automated in part or in full.

Conclusion

Although specific embodiments have been illustrated and described in this specification, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiment shown. This application is intended to cover any adaptations or variations of the present invention. For example, the access device in one embodiment is part of a digital loop carrier. In other embodiments, the access device is located at the central office. Further, in one embodiment, the access device is used with POTS/ISDN TDM services and in other embodiments, the access device implements voice over Internet Protocol (VoIP) applications. In further embodiments, the access device implements any appropriate combination of services whether conventional or later developed.

Claims

What is claimed is:

1. A method for configuring a service type for an access device in a communication system the method comprising: receiving a request for service with a selected service type; downloading an application program for the selected service type to a digital signal processor memory at the access device; defining the service for the access device; defining the service type in a service node; and activating the application on the digital signal processor to provide service with the selected service type.

2. The method of claim 1 , wherein receiving a request for service with a selected service type comprises receiving a request for a service type selected from the group including plain old fashioned telephone service (POTS), integrated service digital network (ISDN) service, El service, Tl service, fractional El service, fractional Tl service, nx64Kbit/s service, high bit-rate digital subscriber line (HDSL/HDSL2), symmetric digital subscriber line (SDSL), a combination of POTS and SDSL, a combination of ISDN and SDSL, asymmetric digital subscriber line (ADSL) service, a combination of POTS and ADSL, a combination of ISDN and ADSL, very high speed digital subscriber line (VDSL) services, a combination of POTS and VDSL, and a combination of ISDN and VDSL.

3. The method of claim 1, and further comprising determining whether a digital signal processor is available to support the request for a service type.

4. The method of claim 1, wherein defining the service for the access device comprises associating the digital signal processor with a generic line card with a port that is coupleable to a subscriber line for the requested service.

5. The method of claim 1 , wherein downloading an application program comprises: determining whether the application program is available at the access device; when not available, downloading the application program to the access device from a head end; and downloading the application program to the digital signal processor memory.

6. The method of claim 1 , wherein downloading an application program comprises: downloading a first application to support a first service type; downloading a second application to support a second service type; and downloading a third application program to act as a digital splitter for the first and second service types.

7. A method for configuring a service type for an access device in a communication system, the method comprising: receiving a request for service with a selected service type; determining whether an application program is available at the access device for the selected service type; when the application program is not available, downloading the application program to the access device from a head end of the telecommunications system; downloading the application program for the selected service type to a digital signal processor memory of a digital processing card at the access device; and associating the digital signal processor of the digital processing card with a generic line card with a port that is coupleable to a subscriber line for the requested service.

8. The method of claim 7, wherein receiving a request for service with a selected service type comprises receiving a request for a service type selected from the group including plain old fashioned telephone service (POTS), integrated service digital network (ISDN) service, El service, Tl service, fractional El service, fractional Tl, nx64Kbit/s service, high bit-rate digital subscriber line (HDSL/HDSL2), symmetric digital subscriber line (SDSL), a combination of POTS and SDSL, a combination of ISDN and SDSL, asymmetric digital subscriber line

(ADSL) service, a combination of POTS and ADSL, a combination of ISDN and

ADSL, very high speed digital subscriber line (VDSL) services, a combination of

POTS and VDSL, and a combination of ISDN and VDSL.

9. The method of claim 7, and further comprising determining whether a digital signal processing card is available to support the request for a service type.

10. The method of claim 7, wherein downloading the application program comprises: downloading a first application to support a first service type; downloading a second application to support a second service type; and downloading a third application program to act as a digital splitter for the first and second service types.

11. A method for establishing a service type for a port of an accesses device in a communication system, the method comprising: configuring a digital processing card at the access device to provide a selected service type for the port; and associating the digital processing card configured for the service type with a generic line card that includes the port and that is operable to provide analog front end processing for the service type.

12. The method of claim 11 , wherein configuring a digital processing card comprises downloading an application program to a digital signal processor memory on the digital processing card.

13. The method of claim 11 , wherein configuring a digital processing card comprises downloading at least two application programs to a digital signal processing memory on the digital processing card.

14. The method of claim 11 , wherein configuring a digital processing card comprises downloading an application program from a head end to the digital processing card.

15. The method of claim 11 , wherein associating the digital processing card configured for the service type with a generic line card comprises identifying the generic line card of the access device that includes the port.

16. An access device, comprising: at least one network termination card providing at least one port that is coupleable to a communication network; at least one generic line card that includes a plurality of ports that are coupleable to subscriber lines, each generic line card further including circuitry that provides analog front end services for the plurality of ports; at least one digital processing card, each digital processing card further including a plurality of digital signal processors; at least one bus that interconnects the at least one network termination card, the at least one generic line card and the at least one digital processing card; and wherein one of the ports of the at least one generic line card is associated with one of the digital signal processors of the at least one digital processing card to provide a selected service type for the port.

17. The access device of claim 16, wherein the at least one bus comprises one of a time division multiplex bus, a packet bus and a combination of a time division bus and a packet bus.

18. The access device of claim 17, wherein the at least one bus comprises a time division multiplex bus and a packet bus, wherein the packet bus is coupled to the at least one network termination card and the at least one digital processing card and the time division multiplex bus is coupled to the at least one generic line card and the at least one digital processing card.

19. The access device of claim 17, wherein the at least one generic line card includes: a time division multiplex bus interface coupled to the at least one bus; and a plurality of analog front end circuits coupled between the ports of the generic line card and the time division multiplex interface, each of the plurality of analog front end circuits including a line interface module and a wide band analog to digital and digital to analog converter.

20. The access device of claim 17, wherein the at least one digital processing card comprises: a time division multiplex bus interface coupled to the at least one bus; a packet bus interface coupled to the at least one bus; and a plurality of digital signal processors, each coupled to both the time division multiplex interface and the packet bus interface.

21. An access device, comprising: at least one generic line card that includes a plurality of ports that are coupleable to subscriber lines, each generic line card further including circuitry that provides analog front end services for the plurality of ports; at least one digital processing card communicatively coupled to the at least one generic line card, each digital processing card further including a plurality of digital signal processors; wherein one of the ports of the at least one generic line card is associated with one of the digital signal processors of the at least one digital processing card to provide a selected service type for the port.

22. The access device of claim 21 , wherein the plurality of digital signal processors each include an associated memory that stores an application program for the selected service type.

23. The access device of claim 21 , and further comprising a controller communicatively coupled to the plurality of digital signal processors that is operable to selectively load an application program in a memory of one of the plurality of digital signal processors to configure the digital signal processor to cooperate with one of the plurality of generic line cards to provide a selected service type for a port of the one of the plurality of generic line cards.

24. The access device of claim 21, wherein each of the at least one generic line cards includes: a plurality of analog front end modules, each including a line interface coupled to a port and a digital to analog and analog to digital converter coupled to the line interface; and a bus interface module coupled to each of the plurality of analog front end modules.

25. The access device of claim 21, wherein each of the at least one digital processing cards includes first and second bus interface modules coupled to the plurality of digital signal processors to provide communication between the at least one digital processing card and the at least one generic line card.

26. The access device of claim 21 , and further including at least one bus for communicatively coupling the at least one generic line card with the at least one digital processing card.

27. The access device of claim 26, wherein the at least one bus includes a time division multiplex bus and a packet bus.

28. A generic line card for an access device of a telecommunications system, the generic line card comprising: a plurality of ports coupleable to subscriber line; a plurality of analog front end modules, each analog front end module including a line interface coupled to one of the plurality of ports and a digital to analog and analog to digital converter coupled to the line interface; a bus interface module coupled to each of the plurality of analog front end modules; and wherein the line card provides analog front end processing for a plurality of service types.

29. The generic line card of claim 28, wherein the bus interface comprises a bus interface for a time division multiplex bus.

30. A digital processing card for an access device of a telecommunications system, the digital processing card comprising: a plurality of digital signal processors that each process digital signals according to selectable service protocols; a first bus interface module, coupled to the plurality of digital signal processors, that provides communication between the plurality of digital signal processors and the associated generic line cards; and a second bus interface module, coupled to the plurality of digital signal processors, that provides communication between the plurality of digital signal processors and the telecommunications system.

31. The digital processing card of claim 30, wherein the first bus interface module comprises an interface for a time division multiplexing bus.

32. The digital processing card of claim 30, wherein the second bus interface module comprises an interface module for a packet bus.

33. The digital processing card of claim 30, wherein only a single time division multiplexing bus serves as both the first and the second busses.