Emergency call monitor

• US 6,600,811 B1
• Filed: 05/07/1999
• Issued: 07/29/2003
• Est. Priority Date: 05/07/1999
• Status: Expired due to Term

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Wolfson, Paul Daniel, Patel, Rajeshkumar Dahyabhai
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): Taylor, Barry W
• Application Number:
  US09/306,952
• Time in Patent Office: 1,544 Days
• Field of Search: 379/34, 379/111, 379/113, 379/133-139, 379/45, 379/9.05, 379/9.06, 379/16, 379/33, 379/9, 379/37, 379/47, 379/46, 379/48, 379/49, 379/42
• US Class Current: 379/45
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

An emergency call monitor (110) monitors the progression of a call in a telephone switching system. The sequence of called digits for a call is detected by a line/trunk interface unit (200). A call-type processor (202) determines whether the call is an emergency call by examining the sequence of called digits and examining a call-type associated with the call. If the call is an emergency call, then a call monitor (204) is initiated to monitor the progression of the call through the telephone switch. If errors are encountered during the call, an alarm (206), including a visual and/or audible indicator, is asserted.

Claims

1. A method for monitoring an emergency call in a telephone switching system comprising the steps of:

A) detecting a predetermined sequence of called digits for a call;

B) determining whether the call is an emergency call by determining whether the predetermined sequence of called digits match a sequence of called digits associated with an emergency call;

C) if the call is an emergency call, then monitoring call processing executing on the telephone switching system associated with the call to determine if the call is completed successfully; and

D) generating an alarm if the call is not completed successfully.

2. The method of claim 1 wherein the predetermined sequence of called digits is 911.

3. The method of claim 1 wherein the step of generating an alarm further comprises generating an alarm if all emergency trunks are one of busy and out of service the call is not completed successfully if the call encounters an error in emergency trunks.

4. The method of claim 3 wherein the error in the emergency trunks is one of busy and out of service.

5. The method of claim 1 wherein the alarm comprises a visible alarm.

6. The method of claim 5 wherein the visible alarm comprises a message on a printer.

7. The method of claim 5 wherein the visible alarm comprises a message on a display.

8. The method of claim 1 wherein the alarm comprises an audible alarm.

9. The method of claim 1 wherein the step of monitoring the call further compromises monitoring the progression of the call to determine if any errors are encountered.

10. The method of claim 1 wherein the step of determining whether the call is an emergency call further comprises determining whether a call type associated with the call indicates that the call is an emergency call.

11. The method of claim 1 wherein the step of generating an alarm further comprises generating an alarm if alternative public safety answering point routing fails for the call.

12. An emergency call monitor in a telephone switching system comprising:

a line/trunk interface unit that receives a telephone call;

a call digit processor coupled to the line/trunk interface unit to detect a predetermined sequence of called digits and a predetermined call type associated with the telephone call, wherein the predetermined sequence of called digits and the predetermined call type identify an emergency call;

a call monitor that is coupled to the call digit processor to monitor call processing executing on the telephone switching system associated with telephone calls that have one of the predetermined sequence of called digits and the predetermined call type, the call monitor providing an indication of a failure if a monitored phone call is not completed successfully; and

an alarm that is activated when the call monitor indicates a failure in the monitored phone call.

13. The monitor of claim 12, wherein the call monitor provides the indication of failure when all emergency trunks are one of busy and out of service.

14. The monitor of claim 12, wherein the predetermined sequence of called digits is 911.

15. The monitor of claim 12, wherein the alarm comprises a visible alarm.

16. The monitor of claim 15 wherein the visible alarm comprises a message on at least one of a printer and display.

17. The monitor of claim 12 wherein the alarm comprises an audible alarm.