Communication server apparatus having four-wire switching interface and method

• US 6,014,431 A
• Filed: 01/10/1997
• Issued: 01/11/2000
• Est. Priority Date: 03/29/1996
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Ham, Ronald E., McCullough, Jason, Sisk, James R., Hall, Clifford L., Locklear, Robert H. Jr., McHale, John F.
• Primary Examiner(s): Kuntz, Curtis A.
• Assistant Examiner(s): Ramakrishnaiah, Melur
• Application Number:
  US08/781,444
• Time in Patent Office: 1,096 Days
• Field of Search: 379/90.01, 379/93.01, 379/93.05, 379/93.08, 379/93.09, 379/93.14, 379/93.15, 379/93.28, 379/93.31, 370/284, 370/285, 370/296, 370/359, 370/434, 370/463, 370/466
• US Class Current: 379/93.14
• CPC Class Codes: H04L 12/2856 Access arrangements, e.g. Internet access asynchronous transfer mode networks H04L12/5601; broadband local area networks H04L12/2801; optical access or distribution networks H04Q11/0067; access to open networks H04L12/5691; digital subscriber line end-user equipment and bit-level processing of data on a PSTN-based network H04M11/00; home network gateways H04L12/2834; wireless access networks H04W
• CPC Class Codes: H04L 12/2889 Multiservice, e.g. MSAN
• CPC Class Codes: H04L 12/4612 LAN interconnection over narrowband networks, e.g. N-ISDN, PSTN, X.25
• CPC Class Codes: H04L 12/5692 Selection among different networks
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04M 11/06 Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04Q 11/0421 Circuit arrangements therefor
• CPC Class Codes: H04Q 2213/13003 Constructional details of switching devices
• CPC Class Codes: H04Q 2213/1302 Relay switches
• CPC Class Codes: H04Q 2213/13036 Serial/parallel conversion, parallel bit transmission
• CPC Class Codes: H04Q 2213/13039 Asymmetrical two-way transmission, e.g. ADSL, HDSL
• CPC Class Codes: H04Q 2213/1304 Coordinate switches, crossbar, 4/2 with relays, coupling field
• CPC Class Codes: H04Q 2213/13093 Personal computer, PC
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13109 Initializing, personal profile
• CPC Class Codes: H04Q 2213/1319 Amplifier, attenuation circuit, echo suppressor
• CPC Class Codes: H04Q 2213/13196 Connection circuit/link/trunk/junction, bridge, router, gateway
• CPC Class Codes: H04Q 2213/13199 Modem, modulation
• CPC Class Codes: H04Q 2213/13203 : Exchange termination [ET]
• CPC Class Codes: H04Q 2213/13204 : Protocols
• CPC Class Codes: H04Q 2213/13213 : Counting, timing circuits
• CPC Class Codes: H04Q 2213/1329 : Asynchronous transfer mode, ATM
• CPC Class Codes: H04Q 2213/13292 : Time division multiplexing, TDM
• CPC Class Codes: H04Q 2213/13299 : Bus
• CPC Class Codes: H04Q 2213/13302 : Magnetic elements
• CPC Class Codes: H04Q 2213/1332 : Logic circuits
• CPC Class Codes: H04Q 2213/13322 : Integrated circuits
• CPC Class Codes: H04Q 2213/1334 : Configuration within the switch
• CPC Class Codes: H04Q 2213/13349 : Network management
• CPC Class Codes: H04Q 2213/13389 : LAN, internet

Abstract

A communication server (58) is provided that includes a plurality of line interface units (500) each coupled to an associated twisted pair data line (54) and to an associated receive data pair (506) and transmit data pair (504). A plurality of XDSL modems (510) are coupled to associated modem receive data pairs (514) and transmit data pairs (512). A switch (502) operates to couple a selected subset of the receive data pairs (506) and transmit data pairs (504) of the line interface units (500) to the modem receive data pairs (514) and transmit data pairs (512) of the XDSL modems (510). A detector (508) operates to detect a need for data service on a receive data pair (506) of a selected line interface unit (500). A controller (80) operates to select one of the XDSL modems (510) in response to detecting the need for data service and to direct the switch (502) to couple the receive data pair (506) and transmit data pair (504) of the selected line interface unit (500) to the modem receive data pair (514) and transmit data pair (512) of the selected XDSL modem (510).

Claims

1. A communication server coupled to a plurality of twisted pair data lines, each twisted pair data line coupled to an associated twisted pair subscriber line by a splitter, the communication server comprising:

a plurality of line interface units, each line interface unit coupled to an associated twisted pair data line and coupled to an associated receive data pair and transmit data pair;

a plurality of XDSL modems, each XDSL modem coupled to an associated modem receive data pair and transmit data pair;

a switch coupled to the receive data pair and transmit data pair of each line interface unit, the switch also coupled to the modem receive data pair and transmit data pair of each XDSL modem, the switch operable to couple a selected subset of the receive data pairs and transmit data pairs of the line interface units to the modem receive data pairs and transmit data pairs of the XDSL modems;

a detector operable to detect a need for data service on a receive data pair of a selected line interface unit; and

a controller coupled to the detector and to the switch, the controller operable to select one of the XDSL modems in response to detecting the need for data service, the controller further operable to direct the switch to couple the receive data pair and transmit data pair of the selected line interface unit to the modem receive data pair and transmit data pair of the selected XDSL modem.

2. The communication server of claim 1, further comprising a plurality of additional detectors, each detector coupled to one of the receive data pairs of the line interface units and operable to detect a need for data service on the receive data pair.

3. The communication server of claim 1, wherein the controller comprises a processor interrupt circuit coupled to a processor, the processor interrupt circuit coupled to the plurality of detectors and operable to sample outputs of the detectors and to provide a signal indicating a detected request for service to the processor.

4. The communication server of claim 1, further comprising polling circuitry having a plurality of inputs coupled to the receive data pairs of a plurality of the line interface units and a single output coupled to the detector, the polling circuitry operable to couple in succession the inputs to the output.

5. The communication server of claim 1, wherein the detector comprises:

a differential receiver coupled to the receive data pair of the selected line interface unit;

a band pass filter coupled to an output of the differential receiver;

a gain device coupled to an output of the band pass filter;

a signal processing circuit coupled to receive an output of the gain device;

a rectifier circuit coupled to an output of the signal processing device;

a low pass filter coupled to an output of the rectifier circuit; and

a voltage comparator coupled to receive as inputs an output of the low pass filter and a reference voltage;

the voltage comparator operable to compare the output of the low pass filter to the reference voltage and to provide a signal indicating a detected need for data service.

6. The communication server of claim 1, wherein the detector comprises:

a differential receiver coupled to the receive data pair of the selected line interface unit;

a band pass filter coupled to an output of the differential receiver;

a gain device coupled to an output of the band pass filter;

a signal processing circuit coupled to receive an output of the gain device; and

a tone decoder circuit coupled to the signal processing circuit, the tone decoder circuit operable to provide a signal indicating a detected need for data service.

7. The communication server of claim 6, wherein the tone decoder circuit comprises a tone decoder integrated circuit.

8. The communication server of claim 1, wherein the detector comprises:

polling circuitry having a plurality of inputs coupled to the receive data pairs of selected line interface units and having a single output, the polling circuitry operable to couple in succession the inputs to the output;

a line receiver coupled to the output of the polling circuitry;

a filter coupled to the line receiver;

an analog/digital converter coupled to receive an output of the filter and operable to convert the output from an analog to a digital signal; and

a digital signal processor coupled to receive the digital signal from the analog/digital converter, the digital signal processor operable to provide a signal indicating a detected need for data service.

9. The communication server of claim 1, wherein each line interface unit comprises:

a line protection circuit coupled to the associated twist pair data line;

a magnetics/hybrid unit coupled to the line protection circuit;

a line receiver coupled to receive an internal receive data pair from the magnetics/hybrid unit;

a receive filter coupled to receive an output of the line receiver and operable to provide the associated receive data pair of the line interface unit;

a transmit filter coupled to receive the associated transmit data pair of the line interface unit;

a cable driver coupled to receive an output of the transmit filter and operable to provide an internal transmit data pair to the magnetics/hybrid unit.

10. The communication server of claim 1, wherein the XDSL modems perform data modulation using asymmetric digital subscriber line technology.

11. The communication server of claim 1, wherein the XDSL modems are operable to receive information at a first rate and to transmit information at a second rate greater than the first rate.

12. The communication server of claim 1, wherein the switch comprises a cross-point matrix switch.

13. The communication server of claim 1, wherein the switch comprises a digital switching matrix.

14. The communication server of claim 1, wherein the switch comprises a frequency multiplexing switch.

15. The communication server of claim 1, further comprising a multiplexer coupled to the XDSL modems, the multiplexer operable to combine information received from the XDSL modems into a single multiplexed signal.

16. A method for coupling a selected subset of a plurality of twisted pair subscriber lines to a plurality of XDSL modems, the method comprising:

splitting each twisted pair subscriber line into a twisted pair data line and a twisted pair phone line;

separating each twisted pair data line into an associated receive data pair and transmit data pair;

detecting a need for data service on a selected receive data pair;

selecting one of the XDSL modems in response to detecting the need for data service, each XDSL modem coupled to an associated modem receive data pair and transmit data pair; and

coupling the selected receive data pair and associated transmit data pair to the modem receive data pair and transmit data pair of the selected XDSL modem.

17. The method of claim 16, wherein detecting comprises coupling, in succession, a detector to the receive data pairs.

18. The method of claim 16, wherein detecting comprises coupling one of a plurality of detectors to each of the receive data pairs.

19. The method of claim 16, wherein coupling is accomplished using a cross-point matrix switch.

20. The method of claim 16, wherein coupling is accomplished using digital switching.

21. The method of claim 16, wherein coupling is accomplished using frequency multiplexing.

22. A method for coupling a selected subset of a plurality of twisted pair data lines to a plurality of XDSL modems, the method comprising:

separating each twisted pair data line into an associated receive data pair and transmit data pair;

detecting a need for data service on a selected receive data pair;

selecting one of the XDSL modems in response to detecting the need for data service, each XDSL modem coupled to an associated modem receive data pair and transmit data pair; and

coupling the selected receive data pair and associated transmit data pair to the modem receive data pair and transmit data pair of the selected XDSL modem.