Circuit to provide backup telephone service for a multiple service access system using a twisted pair

• US 20020027927A1
• Filed: 09/24/2001
• Published: 03/07/2002
• Est. Priority Date: 12/31/1997
• Status: Active Grant

• Current Assignee: Farhad Barzegar, Irwin Gerszberg, Philip Andrew Treventi
• Original Assignee: Farhad Barzegar, Irwin Gerszberg, Philip Andrew Treventi
• Inventors: Gerszberg, Irwin, Barzegar, Farhad, Treventi, Philip Andrew
• Granted Patent: US 6,868,060 B2
• Time in Patent Office: Days
• US Class Current: 370/436
• CPC Class Codes: H04M 3/005 Interface circuits for subscriber lines current supply H04M19/00 and subgroups; supervisory, monitoring or testing arrangements H04M3/22 and subgroups; in key telephone systems H04M9/006
• CPC Class Codes: H04M 3/12 Marking faulty circuits "busy"; Enabling equipment to disengage itself from faulty circuits ; Using redundant circuits; Response of a circuit, apparatus or system to an error
• CPC Class Codes: H04M 3/2209 for lines also used for data transmission
• CPC Class Codes: H04M 3/30 for subscriber's lines , for the local loop

Abstract

A subscriber link to a central office which employs data compression, forward error correction, and advanced modulation techniques and to connect subscribers to multiple communications networks to provide an array of services. A device provides normal telephone service in the event of an equipment failure. At the subscriber end, a server called an intelligent services director (ISD) provides multiple independent connections for telephones which ordinarily connect to multiple access virtual circuits generated on the subscriber link over a twisted pair. A device called a facilities management platform (FMP) at the central office end of the link, among other things, provides interfacing of the subscriber link to various networks including a digital subscriber loop (DLC) and packet switched networks. Ordinarily telephones connected to the ISD require power and correctly functioning modems and controllers in the ISD and the FMP to have access to the outside world. A fail-safe mechanism however allows at least one chosen phone to function in the event of a failure. The chosen phone must be capable of pulse or DTMF dialing. The connection through which it operate can be switched directly to the twisted pair media connecting to the FMP. At the FMP, the twisted pair is switched to tie the connection directly to a line card of the DLC. Alternatively, the ISD contains an interface to a specialized phone designed for the ISD environment. The interface provides the appearance to the DLC of a regular POT.

Claims

1. A fail safe mechanism for a subscriber link over a conductor connecting a subscriber server with at least one telephone device to a telephone network facility, comprising:

a fail safe connection in said subscriber server for said at least one telephone device, said fail safe connection being switchable between a normal position connecting said at least one telephone device to said subscriber server and a backup position connecting directly to said conductor;

said telephone network facility having a telephone network termination configured to connect an analog telephone;

a network interface terminating a link layer of said subscriber link at said telephone network facility;

a switch on said network interface such that said conductor is switchable between said network interface and said termination, whereby said at least one telephone device is connectable to said telephone network termination when said fail safe connection is in said backup position; and

an analog interface in one of said subscriber server and said at least one telephone device connected to permit said at least one telephone to function as an analog telephone.

2. A mechanism as in claim 1, wherein said telephone network termination provides battery-backup power for said analog telephone.

3. A safety device for multiple access subscriber link over a wire pair connecting a subscriber server to at least first and second network interfaces, said first network interface having a port directly connectable by a conductor to a phone such that said phone is operable without power being supplied from said phone, said device comprising:

a remote modem at said second network interface connected to said subscriber link;

a local modem of said server in communication with said remote modem over said subscriber link;

a telephone using a first of a frequency spectrum of said subscriber link

said local modem and said remote modem using a second portion of said frequency spectrum;

said telephone being connected directly to said remote modem through said wire pair at said remote end, said remote end of said wire being one of connected to said port of directly and selectably through a switch.

4. A device as in claim 3, wherein said remote end of said wire is connected to said port selectably through a switch controlled by a controller.

5. A device as in claim 4, wherein said controller closes said switch responsively to an occurrence of a failure of one of said remote and said local modems.

6. A device as in claim 4, wherein said controller closes said switch responsively to a failure to receive at said local modem a message from said remote modem or a failure to receive at said remote modem a message from said local modem.

7. A device as in claim 4, wherein said remote end of said wire is connected to said port selectably through a switch that defaults to connect said remote end to said port when power to said switch is lost.

8. A safety system for a multiple access subscriber link over a conductor between a local server and a remote network interface, said remote network interface capable of providing access for said subscriber link to multiple networks including at least one broadband network providing non-dedicated time-variable allocation of band-width and at least one narrowband network providing dedicated band-width through a switch, said narrowband network being accessible through a port directly connectable by a conductor to a plain old telephone (POT) such that said phone is operable without power being supplied from said POT, said system, comprising:

a switch for connecting conductor remote end to said port;

a POT connectable by said server to said conductor at a conductor local end;

remote and local modems linked at said conductor remote and local ends, respectively, said modems configured to modulate data signals to be applied to said to least one broadband network at a range of frequencies above a range of frequencies used by said POT.

9. A safety system for a multiple access subscriber link over a conductor between a local server and a remote network interface, said remote network interface capable of providing access, for said subscriber link to multiple networks including at least one broadband network providing non-dedicated time-variable allocation of band-width and at least one narrowband network providing dedicated band-width through a switch, said narrowband network being accessible through a port directly connectable by a conductor to a plain old telephone (POT) such that said phone is operable without power being supplied from said POT, said system, comprising:

a switch for connecting conductor remote end to said port;

telephone connectable by said server to said conductor at a conductor local end;

said server having an interface interposed between said telephone and sad conductor local end configured to make said telephone function as a POT by providing analog signaling over said conductor in a first range of frequencies;

remote and local modems linked at said conductor remote and local ends, respectively, said modems configured to modulate data signals to be applied to said to least one broadband network at a range of frequencies above said first range of frequencies.