# Patent

## Title
Method of providing 911 service

## Abstract

A method of providing 911 service to a private branch exchange, includes grouping a plurality of private telephone numbers into a set. An outgoing telephone line for a 911 call is assigned to the set. A location information for the outgoing telephone line is input into a location database.

## Background
RELATED APPLICATIONS
The present application is a continuation of U.S. application Ser. No. 10/635,132, filed Aug. 6, 2003, now U.S. Pat. No. 6,950,499, which is a continuation of U.S. application Ser. No. 10/278,602, filed Oct. 23, 2002, now U.S. Pat. No. 6,650,733, which is a continuation of U.S. application Ser. No. 10/093,749, filed Mar. 8, 2002, now U.S. Pat. No. 6,501,831, which is a continuation of U.S. application 09/642,430, filed Aug. 21, 2000, now U.S. Pat. No. 6,415,019.


FIELD OF THE INVENTION
The present invention relates to generally to the field of 911 emergency service systems and more particularly to a method of providing 911 service to a private branch exchange.
BACKGROUND OF THE INVENTION
A Public Safety Answering Point (PSAP) uses an automatic location identification (ALI) information provided with the automatic number identification (ANI) to determine the location of a 911 telephone call. Unfortunately, when a 911 call is placed from a business having a PBX (Private Branch Exchange), the PSAP only receives the billing address of the business. For large businesses having multiple locations, this does not provide any useful information. Some PBX providers allow the owners to enter in correct location information for all their lines. Unfortunately, this is time consuming and therefor rarely is done.
Thus there exists a need for a method of providing 911 service to a private telephone numbering system that is easy to setup.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of public safety answering service for a private telephone numbering system in accordance with one embodiment of the invention.
FIG. 2 is a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention;
FIG. 3 is a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention; and
FIGS. 4 & 5 are a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention.



DETAILED DESCRIPTION OF THE DRAWINGS
A method of providing 911 service to a private branch exchange, includes grouping a plurality of private telephone numbers into a set. An outgoing telephone line for a 911 call is assigned to the set. A location information for the outgoing telephone line is input into a location database (E911 database). By grouping the telephone lines significantly less information has to be input into the location database. The groups are selected to be telephone lines in a set geographic area. For instance all the telephones on the third floor of a small building might be grouped together. This provides emergency personnel with plenty of information to locate the emergency.
FIG. 1 is a block diagram of public safety answering service for a private branch exchange in accordance with one embodiment of the invention. A public safety answering point (PSAP) 10 includes a switch 12 connected to a SSP (Service Switching Point) 14. The switch 12 triggers on incoming call and forms a location query. The location query is set to a location database (E911 database) 16. The call and location information are forwarded to one of a plurality of operators 19.
A company 20 using a PBX 22 groups private telephone lines according to their location. This company 20 has two locations 24, 26. Any 911 call from the first location 24 is routed over a predetermined public telephone line 28. Any 911 call from the second location 26 is routed over a predetermined public telephone line 30. The PBX 22 is connected to a SSP 32. A 911 call is then sent to SSP 14 and to the PSAP 10. A SCP (Service Control Point) 34 is connected through an intelligent network to the SSPs 14, 32. The SCP 34 may provide routing information to the SSP 32 for 911 calls. A second company 36 also has a PBX 38. The company 36 also divides its telephones into two locations 38, 40. Note that any number of locations could be handled and the invention encompasses more than a single PBX. A 911 call from any of the telephones in the first location 38 are routed over a predetermined external telephone line 42. A 911 call from any of the telephones in the second location 40 are routed over a predetermined external telephone line 44.
FIG. 2 is a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention. The process start, step 60, by grouping a plurality of telephone numbers into a set at step 62. An outgoing telephone line for a 911 call is assigned to the set at step 64. At step 66, a location information for the outgoing telephone line is input into a location database of a telephone company which ends the process at step 68. In one embodiment, the plurality of private telephone numbers are selected by an origination location. In one embodiment a private branch exchange is programmed to select the outgoing telephone line when a 911 call is received from one of the plurality of private telephone numbers.
In one embodiment when the 911 call is dialed from one of the plurality of, private telephone numbers, the 911 call is sent out over the outgoing telephone line. The 911 call is triggered on at a service switching point. A routing query is transmitted to a switching control point (SCP). A routing instruction is received from the SCP. The 911 call is routed to a proper PSAP. A location database is queried for a location associated with a telephone number of the outgoing telephone line.
FIG. 3 is a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention. The process starts, step 80, by receiving a 911 call at a private switch at step 82. In one embodiment, the private switch is a private branch exchange. A dialing telephone number is determined at step 84. An associated outgoing telephone line is looked up at step 86. At step 88, the 911 call is placed over the associated outgoing telephone line which ends the process at step 90. The 911 call is received at a service switching point (SSP). The 911 call is triggered on and the SSP sends a query to a switching control point (SCP). A response is received that includes a routing instruction. In one embodiment the response includes the number of the associated outgoing telephone line. The 911 call is routed to a public safety answering point (PSAP). A location query is sent to a location database. The 911 call is forwarded to an operator. A location information is transmitted to the operator.
In one embodiment, a first plurality of private telephone numbers are grouped into a first set. A second plurality of private telephone numbers are grouped into a second set. One of a plurality of outgoing telephone lines is assigned to the first set. A second of the plurality of outgoing telephone lines is assigned to the second set. The location database is programmed to include a location for the one of the plurality of outgoing telephone lines and a second location for the second of the plurality of outgoing telephone lines.
FIGS. 4 & 5 are a flow chart of the steps used in a method of providing 911 service to a private branch exchange in accordance with one embodiment of the invention. The process starts, step 100, by grouping a first plurality of private telephone numbers into a first set at step 102. A second plurality of private telephone numbers is grouped into a second set at step 104. One of a plurality of outgoing telephone lines is assigned to the first set at step 106. A second of the plurality of outgoing telephone lines is assigned to the second set at step 108. A location database is programmed to include a location for the one of the plurality of outgoing telephone lines at step 110. The location database is programmed to include a second location for the second of the plurality of outgoing telephone lines at step 112. A 911 call is received at a private switch at step 114. A dialing telephone number is determined at step 116. At step 118 it is determined if the dialing telephone number belongs in the first set or the second set. When the dialing telephone number belongs in the first set at step 120, the 911 call is placed over the one of the plurality of outgoing telephone lines which ends the process at step 122. , When the dialing telephone number belongs in the second set, the 911 call is placed over the second of the plurality of outgoing telephone lines. The 911 call is received at a service switch point. The 911 call is triggered on and a query is sent to a switching control point. A response is received that includes a routing instruction. The 911 call is routed to a public safety answering point. A location query is sent to the location database. The call is forwarded to an operator. A location information is transmitted to the operator.
Thus there has been described a method of providing 911 service to a private telephone numbering system that is easy to setup.
The methods described herein can be implemented as computer-readable instructions stored on a computer-readable storage medium that when executed by a computer will perform the methods described herein.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims.

## Claims

1. A method of providing 911 service, comprising:
determining if a 911 call has been placed;
when the 911 call has been placed, inherently determining at a private branch exchange a location of a telephone placing the 911 call by looking up an outgoing telephone line associated with the telephone placing the 911 call; and
routing the 911 call to a service switching point after the location of the telephone has been determined.

2. The method of claim 1, further including:
routing the 911 call to a public safety answering point via the outgoing telephone line.

3. The method of claim 1, further including:
selecting an internal telephone line;
determining a location of a telephone associated with the internal telephone line;
assigning the outgoing telephone line to the internal telephone line for 911 calls.

4. The method of claim 3, further including:
entering location information in association with the outgoing telephone line in a location database to indicate the physical location of telephones placing 911 calls over the outgoing telephone line.

5. A method providing 911 service, comprising:
identifying a telephone placing a 911 call at a private branch exchange;
selecting an outgoing telephone line for the 911 call based on the identity of the telephone placing the 911 call; and
placing the 911 call via the outgoing telephone line to indicate a physical location of the telephone placing the 911 call.

6. The method as defined in claim 5 wherein an identity of the outgoing telephone line is inherently indicative of the physical location of the telephone placing the 911 call.