Method and apparatus for switching between multiple communication lines

• US 6,788,782 B1
• Filed: 01/20/2000
• Issued: 09/07/2004
• Est. Priority Date: 01/20/2000
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Turner, Earl, Fotsch, Don
• Primary Examiner(s): NGUYEN, DUC MINH
• Application Number:
  US09/488,340
• Time in Patent Office: 1,692 Days
• Field of Search: 379/207.02, 379/207-4-2, 379/219, 379/220.01, 379/221-1-2, 379/317, 379/333-334, 379/335-337
• US Class Current: 379/334
• CPC Class Codes: H04M 1/71 Substation extension arrangements
• CPC Class Codes: H04M 1/715 using two or more extensions per line cordless telephones H04M1/725
• CPC Class Codes: H04M 1/738 Interface circuits for coupling substations to external telephone lines H04M1/78 takes precedence

Abstract

Disclosed is an apparatus and method for switching between two network lines, such as telephone subscriber lines. Households and offices are increasingly equipped with multiple network lines for voice and data communications. The line switching unit of the present invention has a first terminal for receiving a CPE line from a CPE device. First and second switches of the unit each connect a common terminal to a first switched terminal responsive to a first value of a control signal received at a control terminal of each switch and to a second switched terminal responsive to a second value of the control signal. The first switched terminal of the first switch is connected to the first terminal and the second switched terminal of the second switch is connected to the first terminal. The common terminal of the first switch is connected to a first network line and the common terminal of the second switch is connected to a second network line. A further aspect of the present invention includes a control unit that senses an off-hook signal on the CPE line and, when the control signal is in a state of outputting the first value, checks a state of the first network line to determine if it is in use. If the first network line is in use, then the control unit checks a state of the second network line. If the second network line is not in use, then the control unit changes the state of the control signal to output the second value of the control signal.

Claims

1. A line switching apparatus for switching between first and second network lines, the apparatus comprising:

a first terminal for receiving a first CPE line, the first terminal having first and second nodes;

a first switching device having a common terminal for receiving a first network line, first and second switched terminals, and a control terminal for receiving a control signal, where the first switching device is configured to electrically couple the common terminal to the first switched terminal responsive to a first value of the control signal and electrically couple the common terminal to the second switched terminal responsive to a second value of the control signal, where the first switched terminal of the first switching device is coupled to the first node of the first terminal;

a second switching device having a common terminal for receiving a second network line, first and second switched terminals, and a control terminal for receiving the control signal, where the second switching device is configured to electrically couple the common terminal to the second switched terminal responsive to a first value of the control signal and electrically couple the common terminal to the second switched terminal responsive to a second value of the control signal, where the second switched terminal of the second switching device is coupled to the second node of the first terminal.

2. The apparatus of claim 1, the apparatus further including a control unit, the control unit having a control output terminal for generating the control signal, a first CPE line input for receiving the first CPE line, a first network line input for receiving status information for the first network line and a second network line input for receiving status information for the second network line, the control unit being configured to store and output on the control output terminal one of the first and second values of the control signal, and the control unit being further configured to receive a connection request signal over the first CPE line and, responsive thereto, check the status information for the first network line when the first value of the control signal is stored and output to determine whether the first network line is in use and, when the first network line is in use, check the status information for the second network line and, when the second network line is not in use, change the control signal to the second value.

3. The apparatus of claim 2, the apparatus further including a display unit having an input terminal and being configured to display a message responsive to a message signal, and where the control unit further includes a message output terminal for outputting the message signal, the message output terminal being coupled to the input terminal of the display unit.

4. The apparatus of claim 2, the apparatus further including:

a first codec having an input terminal coupled to the first network line and an output terminal coupled to the first network line input of the control unit; and

a second codec having an input terminal coupled to the second network line and an output terminal coupled to the second network line input of the control unit.

5. The apparatus of claim 1, wherein the apparatus is further configured to be a functional unit integrated into a CPE device coupled to the first CPE line.

6. The apparatus of claim 1, the apparatus further including a second terminal for receiving a second CPE line, the second terminal having first and second nodes, the first node of the second terminal being coupled to the second switched terminal of the first switching device and the second node of the second terminal being coupled to the first switched terminal of the second switching device.

7. The apparatus of claim 6, the apparatus further including a control unit, the control unit having a control output terminal for generating the control signal, a first CPE line input for receiving the first CPE line, a second CPE line input for receiving the second CPE line, a first network line input for receiving status information for the first network line and a second network line input for receiving status information for the second network line, the control unit being configured to:

store and output on the control output terminal one of the first and second values of the control signal;

receive a connection request signal over the first CPE line and, responsive thereto, check the status information for the first network line when the first value of the control signal is stored and output to determine whether the first network line is in use and, when the first network line is in use, check the status information for the second network line and, when the second network line is not in use, change the control signal to the second value; and

receive a connection request signal over the second CPE line and, responsive thereto, check the status information for the second network line when the first value of the control signal is stored and output to determine whether the second network line is in use and, when the second network line is in use, check the status information for the first network line and, when the first network line is not in use, change the control signal to the second value.

8. A method for switching between first and second network lines simultaneously providing service to a customer premises, the method comprising the steps of:

coupling a first CPE line through a first switching device to the first network line;

coupling the first CPE line through a second switching device to the second network line;

generating and storing a control signal, where the first CPE line is electrically connected to the first network line responsive to a first value of the control signal and the first CPE line is electrically isolated from the first network line responsive to a second value of the control signal, and where the first CPE line is electrically isolated from the second network line responsive to the first value of the control signal and electrically connected to the second network line responsive to the second value of the control signal;

coupling a second CPE line through the first switching device to the first network line, where the second CPE line is electrically connected to the first network line responsive to the second value of the control signal and electrically isolated from the first network line responsive to the first value of the control signal; and

coupling the second CPE line through a second switching device to the second networks line, where the second CPE line is electrically connected to the second network line responsive to the first value of the control signal and electrically isolated from the second network line responsive to the second value of the control signal.

9. The method of claim 8, further including the steps of:

receiving a connection request on the first CPE line;

when the control signal has the first value, checking whether the first network line is in use and, when the first network line is in use, switching the control signal to the second value;

when the control signal has the second value, checking whether the second network line is in use and, when the second network line is in use, switching the control signal to the first value.

10. The method of claim 9, further including the step of outputting a message to a display indicating that the first network line is in use when switching the control signal to the second value.

11. The method of claim 10, further including the step of outputting a second message to a display indicating that the second network line is in use when switching the control signal to the first value.

12. The method of claim 8, the method further including the steps of:

receiving a connection request on the second CPE line;

when the control signal has the first value, checking whether the second network line is in use and, when the second network line is in use, switching the control signal to the first value;

when the control signal has the second value, checking whether the first network line is in use and, when the first network line is in use, switching the control signal to the second value.

13. The method of claim 12, the method further including the step of outputting a message to a display indicating that the second network line is in use when switching the control signal to the second value.