Telephonic communications – Emergency or alarm communications – Central office responsive to emergency call or alarm
Reexamination Certificate
2001-06-07
2002-07-30
Ramakrishnaiah, Melur (Department: 2643)
Telephonic communications
Emergency or alarm communications
Central office responsive to emergency call or alarm
C379S049000, C379S221080, C370S410000
Reexamination Certificate
active
06427001
ABSTRACT:
BACKGROUND
1. Field of Invention
The present invention relates generally to the field of telecommunication systems. More particularly the present invention relates to the field of notifying parties that a telephone call to 911 has been placed.
2. Background of the Invention
Telephone calls to 911 are generally routed to a public safety answering point (PSAP). The PSAP is a center containing 911 operators (or agents) who coordinate emergency services to respond to the 911 call. Generally, when a person places a 911 call, the call is routed through a central office (CO) through a tandem to the PSAP. An agent at the PSAP answers the call and provides whatever assistance is required to handle the emergency.
A database called an automatic location information (ALI) database is associated with the PSAP. The ALI database is generally part of a database management system having a database server through which the ALI database is queried. The ALI database contains records that associate telephone numbers with names and locations. When a call is made to 911, the PSAP queries the ALI database for location and name information. The query contains the telephone number associated with the telephone that made the 911 call. The ALI database passes the name and location information back to the PSAP in response to the query. This information can be made available to the agents in well-known ways.
There are often times when people would want to be notified that a 911 call has been made. For example, if a babysitter watching a child places an emergency telephone call to 911, that child's parent, other relative, neighbor and/or others might want to be notified of the 911 call. Generally, to provide such service, subscribers to a 911 notification service provide a list of telephone numbers to be called when any telephone associated with a particular telephone number dials 911 (notification list). When someone dials 911 from a phone associated with a phone number for which the service has been provisioned, all the telephone numbers in the notification list are notified of the telephone call. For example, in the case above, parents, friends or anyone else whose phone number is on the notification list can be notified of the 911 despite being located remotely from the telephone making the call, and not being co-located with one another.
One conventional system for 911 telephone call notification, provided by Lucent, makes use of the system control point (SCP) of the public-switched telephone system (PSTN). An office-wide trigger is established at the CO. The trigger activates when a telephone line served by the CO dials 911. The particular trigger used by Lucent is the NXX trigger. When someone that is served by the CO dials 911, the office-wide NXX trigger is activated. This causes the CO to suspend the call and send a query message to the SCP to determine how to process the call. The query message contains the subscriber's telephone number. The SCP extracts the subscriber's telephone number and sends a message back to the CO instructing the CO to complete the 911 call to the PSAP through the tandem.
Using the extracted subscriber's telephone number, the SCP then performs a database lookup to find the notification list provided by the subscriber containing the telephone numbers of those persons to notify of the 911 call. The SCP forwards this notification list to a service node (SN). As is well-known to those skilled in the art, the SN has outbound dialing capability. The SN dials each number on the list provided by the SCP to notify those persons on the list that the 911 call was made.
To get the notification list to the SCP database, Lucent sets up a web site that users can access through the Internet. Users can enter the information into a web page that is provided by the web site on a web server. The web server associated with the web site transmits this information to a services management system (SMS) associated with the PSTN. The SMS is a data distribution system that distributes data to SCPs in the PSTN. In this case, the SMS transfers the subscriber-entered notification list to the correct SCP, i.e., the SCP associated with the CO that homes the subscriber's telephone number.
There are several problems associated with the 911 notification system described above. For example, the SN is very expensive to use for outbound dialing purposes. Another significant disadvantage arises because of the use of the trigger. Processing the trigger adds from 100 milliseconds to 6 seconds to the time required to complete the call. Adding time to call completion is highly undesirable in the context of 911 calls, where seconds can save lives.
A second prior art system for 911 notification is provided in U.S. Pat. No. 6,151,385 to Reich et al (“Reich”). In Reich, there is no trigger set up. Rather, the CO completes the call to the PSAP through the tandem. In Reich, a patch is put into the ALI database server. When there is a query to the ALI database, a message is sent to an outbound dialing system or an operator that makes the outbound calls. The message contains the telephone number in the ALI query. As described above, this telephone number is the telephone number that is associated with the telephone that made the 911 call.
In Reich, there is a computer associated with the outbound dialing system or operator. This computer system receives the message from the ALI database. Using the phone number contained in the message, the computer system obtains a notification list of telephone numbers to call to notify other of the 911 call. The notification list is forwarded to the outbound dialing system, which dials the telephone numbers on the notification list to notify those on the list of the 911 call. Alternately, the notification list is forwarded to an operator who then places outbound calls to the telephone numbers on the list to make the notifications.
In Reich, subscribers create notification lists using the Internet to access a web site. Subscribers fill out a notification list form on a web page provided by the web site. The notification list is then stored on a web server associated with the web site or other file storage system associated with the web site.
Reich's system has the advantage of not delaying the 911 call as in the Lucent system described above. However, there are several disadvantages with the system described in Reich. One disadvantage is that Reich's system requires a change to the existing 911 infrastructure. That change is the patch that must be made for the ALI database server so that it sends a message containing the telephone number associated with the telephone making the 911 call to the computer system. Another disadvantage is that due to government regulations, telephone companies are not always free to send calling party name information (CPNI) to third party companies without consent. That is, for at least some numbers, regulations may prohibit a telephone company from sending the telephone number associated with the telephone making the 911 call to the computer system.
A third system for notifying other parties of 911 calls is described in U.S. Pat. No. 5,195,126 to Carrier et al (“Carrier”). Carrier describes a system for monitoring the voice telephone trunks between a central office and the tandem to see if a 911 call has been sent. Carrier describes using in-band signaling to determine whether a 911 call has been sent, i.e., Carrier analyzes the DTMF tones being sent to see if a 911 call has been placed.
As described in Carrier, a trunk monitoring device monitors one or more trunks on the output of the tandem for calls to 911. If a 911 call is detected using in-band signaling techniques, the monitoring device makes an outbound notification using a voice messaging system (VMS) that is available in the PSTN. The monitoring device obtains a notification list from a subscriber database.
A significant problem with this system is deciding which of the many trunks should be monitored. If not all trunks are monitored, then some 911 calls might be
Contractor Sunil H.
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