Call-load-control arrangement for an emergency-call-answering center

• US 5,249,223 A
• Filed: 01/03/1991
• Issued: 09/28/1993
• Est. Priority Date: 01/03/1991
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: AT&T, Inc.
• Inventors: Vanacore, Vincent D.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Hong, Harry S.
• Application Number:
  US07/637,249
• Time in Patent Office: 999 Days
• Field of Search: 379/37, 379/45, 379/201, 379/265, 379/266, 379/309, 379/207, 379/219, 379/113, 379/221, 379/210, 379/214
• US Class Current: 379/266.06
• CPC Class Codes: H04M 2242/22 Automatic class or number identification arrangements
• CPC Class Codes: H04M 3/36 Statistical metering, e.g. recording occasions when traffic exceeds capacity of trunks
• CPC Class Codes: H04M 3/42102 Making use of the called party identifier
• CPC Class Codes: H04M 3/51 Centralised call answering arrangements requiring operator intervention , e.g. call or contact centers for telemarketing
• CPC Class Codes: H04M 3/5116 for emergency applications
• CPC Class Codes: H04M 3/523 with call distribution or queueing
• CPC Class Codes: H04M 3/5237 Interconnection arrangements between ACD systems
• CPC Class Codes: H04Q 2213/13072 Sequence circuits for call signaling, ACD systems
• CPC Class Codes: H04Q 2213/13564 load balancing
• CPC Class Codes: H04Q 3/0016 Arrangements providing connection between exchanges
• CPC Class Codes: H04Q 3/0029 Provisions for intelligent networking
• CPC Class Codes: H04Q 3/66 Traffic distributors
• CPC Class Codes: H04Q 3/72 Finding out and indicating number of calling subscriber

Abstract

A call-load control arrangement for a first call-answering center, such as an E911 service PSAP, causes calls destined for the first center and not yet routed thereto to be rerouted by a central office from the central office directly to a second, alternate, call-answering center while the first center is in call overload. A function monitors current parameters of call-answering performance of the first center and periodically compares them against predetermined criteria of acceptable call-answering performance to determine whether call overload exists. In the E911 service PSAP, the function automatically closes and opens a switch to activate and deactivate the "night-service" or "trunk make-busy" link to cause the central office respectively to reroute calls away from, or to route calls to, the PSAP.

Claims

1. A call-load control arrangement comprising:

a primary call-answering center;

an alternate call-answering center;

a call-routing node for routing calls to the call-answering centers;

first means in the primary call-answering center for automatically periodically determining whether a call, routed to the primary call-answering center while the primary call-answering center is in service, is likely to be answered within a predetermined period of time;

second means in the primary call-answering center, responsive to a determination that the call is unlikely to be answered within the predetermined period of time, for commanding the call-routing node to not route calls to the primary call-answering center; and

third means in the call-routing node responsive to absence of the command, for routing calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to the primary call-answering center, and responsive to the command, for routing the calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to the alternate call-answering center.

2. The arrangement of claim 1 wherein the first means comprise

means for automatically periodically checking parameters of call-answering performance of the primary call-answering center while the primary call-answering center is in service to determine from the parameters whether a call routed to the primary call-answering center is likely to be answered within a predetermined period of time.

3. The arrangement of claim 1 wherein the first means comprise

means for determining whether a predetermined percentage of calls most recently answered by the primary call-answering center have each been answered within a predetermined first time limit,

means for determining whether any call waiting to be answered by the primary call-answering center has been waiting longer than a predetermined second time limit, and

means for determining whether a number of calls waiting to be answered by the primary call-answering center exceeds a predetermined third number limit;

and wherein

the second means command the call-routing node to commence to route the calls to the primary call-answering center, in response to a determination that none of the first, the second, and the third limits have been exceeded, and command the call-routing node to cease to route the calls to the primary call-answering center, in response to a determination that the first and the second limits have both been exceeded; and

the third means respond to the command to commence by routing the calls to the primary call-answering center, and respond to the command to cease by routing the calls to the alternate call-answering center.

4. The arrangement of claim 1 further comprising:

at least one first trunk interconnecting the primary call-answering center with the call-routing node and normally used for carrying calls that are routed to the primary call-answering center; and

at least one spare trunk interconnecting the primary call-answering center with the call-routing node, normally not used and used when the at least one first trunk is out of service for carrying calls that are normally carried by the at least one first trunk.

5. A call-load control arrangement comprising:

means for routing calls to call-answering centers;

first means in a primary call-answering center for automatically periodically checking parameters of call-answering performance of the primary call-answering center while the primary call-answering center is in service, to determine from the parameters whether a call that has not yet been routed to the primary call-answering center is likely to be answered within a predetermined period of time if it were routed to the primary call-answering center;

second means in the primary call-answering center, responsive to a determination that the call is unlikely to be answered within the predetermined period of time, for commanding the call-routing means to not route calls to the primary call-answering center; and

the call-routing means are responsive to absence of the command, for routing calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to the primary call-answering, and responsive to the command, for routing the calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to an alternate call-answering center.

6. The arrangement of claim 5 wherein the first means comprise

means for determining whether a predetermined percentage of calls most recently answered by the primary call-answering center have each been answered within a predetermined first time limit,

means for determining whether any call waiting to be answered by the primary call-answering center has been waiting longer than a predetermined second time limit, and

means for determining whether a number of calls waiting to be answered by the primary call-answering center exceeds a predetermined third number limit;

and wherein

the second means command the call-routing means to commence to route the calls to the primary call-answering center, in response to a determination that none of the first, the second, and the third limits have been exceeded, and command the call-routing means to cease to route the calls to the primary call-answering center, in response to a determination that the first and the second limits have both been exceeded; and

the call routing means respond to the command to commence by routing the calls to the primary call-answering center, and respond to the command to cease by routing the calls to the alternate call-answering center.

7. The arrangement of claim 5 further comprising:

at least one first trunk extending from the call-routing means to the primary call-answering center and normally used for carrying calls that are routed to the primary call-answering center; and

at least one spare trunk extending from the call-routing means to the primary call-answering center, normally not used and used when the at least one first trunk is out of service for carrying calls that are normally carried by the at least one first trunk.

8. An arrangement for controlling a call load of a call-answering center that has a signaling connection to a call-routing node which connection, when activated, causes the routing node to reroute calls destined for the call-answering center to an alternate call-answering center, comprising:

first means in the call-answering center for automatically periodically determining whether a call routed to the center while the center is in service is likely to be answered within a predetermined period of time;

second means in the call-answering center, responsive to each determination by the first means that the call is likely to be answered within the predetermined period of time, for automatically ensuring deactivation of the signaling connection to cause calls that have not yet been routed to the center to be routed to the center; and

third means in the call-answering center, responsive to each determination by the first means that the call is likely not to be answered within the predetermined period of time, for automatically ensuring activation of the signaling connection to cause calls that have not yet been routed to the center to be routed to an alternate call-answering center.

9. The arrangement of claim 8 wherein the first means comprise means for automatically periodically checking parameters of call-answering performance of the center while the center is in service to determine from the parameters whether a call routed to the center is likely to be answered within a predetermined period of time.

10. The arrangement of claim 9 for a center that has a queue for calls waiting to be answered by the center, wherein the first means comprise

means for determining whether a predetermined percentage of calls most recently answered by the center have each been answered within a predetermined first time limit,

means for determining whether any call waiting in the queue has been waiting longer than a predetermined second time limit, and

means for determining whether a number of calls waiting in the queue exceeds a predetermined third number limit;

wherein

the second means ensure deactivation of the signaling connection in response to determinations that none of the first, the second, and the third limits have been exceeded; and

wherein

the third means ensure activation of the signaling connection in response to determination that the first and the second limits have both been exceeded.

11. The arrangement of claim 8 for a center that has a queue for calls that have been routed to and are waiting to be answered by the center, wherein

the signaling connection while active causes calls not yet routed to the center to be routed from the node directly to an alternate call-answering center, and causes calls already routed to the center to remain routed from the node to the center.

12. The arrangement of claim 8 wherein

the second means ensure deactivation by maintaining deactivated the signaling connection when it is not active and deactivating the signaling connection when it is active;

and

the third means ensure activation by maintaining activated the signaling connection when it is active and activating the signaling connection when it is not active.

13. The arrangement of claim 8 for an emergency-call-answering center wherein

calls routed to the center are emergency calls.

14. The arrangement of claim 8 for controlling the call load of a call-answering center that further has at least one first trunk interconnecting the call-answering center with the call-routing node normally used for carrying calls that are routed to the call-answering center, further comprising:

at least one spare trunk interconnecting the call-answering center with the call-routing node, normally not used and used when the at least one first trunk is out of service for carrying calls that are normally carried by the at least one first trunk.

15. An arrangement for controlling an emergency-call load of an emergency-call-answering center that has a manually-activateable "night service" or "trunk make-busy" signaling connection to a central-office switch which connection, when activated, places the call-answering center out of service and causes the switch to reroute calls destined for the call-answering center to an alternate call-answering center, comprising:

first means in the emergency-call-answering center for automatically periodically determining whether an emergency call routed to the emergency-call-answering center while the emergency-call-answering center is in service is likely to be answered within a predetermined period of time;

second means in the emergency-call-answering center, responsive to each determination by the first means that the emergency call is likely to be answered within the predetermined period of time, for automatically deactivating the signaling connection if it is activated, to cause emergency calls that have not yet been routed to the emergency-call-answering center to be routed to the emergency-call-answering center; and

third means in the emergency-call-answering center, responsive to each determination by the first means that the emergency call is likely not to be answered within the predetermined period of time, for automatically activating the signaling connection if it is deactivated to cause emergency calls that have not yet been routed to the emergency-call-answering center to be routed to an alternate emergency-call-answering center.

16. The arrangement of claim 15 for controlling the emergency-call load of an emergency-call-answering center that further has a plurality of first emergency-call trunks interconnecting the emergency-call-answering center with the central-office switch normally used for carrying emergency calls that are routed to the emergency-call-answering center, further comprising:

at least one spare trunk interconnecting the emergency-call-answering center with the central-office switch, normally not used and used when at least one of the first trunks is out of service for carrying calls that are normally carried by the out-of-service first trunk.

17. A method of controlling the call-load experienced by a call-answering center in a system having a primary call-answering center, an alternate call-answering center, and a call-routing node for routing calls to the call-answering centers, the method comprising the steps of:

automatically periodically determining in the primary call-answering center whether a call routed to the primary call-answering center while the primary call-answering center is in service is likely to be answered within a predetermined period of time;

in response to a determination that the call is unlikely to be answered within the predetermined period of time, commanding the call-routing node from the primary call-answering center to not route calls to the primary call-answering center; and

in response to absence of the command, routing calls, that have not yet been routed to a call-answering center and are destined for the primary call-answering center, from the call-routing node to the primary call-answering center; and

in response to the command, routing the calls, that have not yet been routed to a call-answering center and are destined for the primary call-answering center, from the call-routing node to the alternate call-answering center.

18. The method of claim 17 wherein the step of determining comprises the step of:

automatically periodically checking parameters of call-answering performance of the primary call-answering center while the primary call-answering center is in service to determine from the parameters whether a call routed to the primary call-answering center is likely to be answered within a predetermined period of time.

19. The method of claim 17 wherein

the step of determining comprises the step of

determining whether a predetermined percentage of calls most recently answered by the primary call-answering center have each been answered within a predetermined first time limit,

determining whether any call waiting to be answered by the primary call-answering center has been waiting longer than a predetermined second time limit, and

determining whether a number of calls waiting to be answered by the primary call-answering center exceeds a predetermined third number limit;

the method further comprises the step of

commanding the call-routing node to commence to route the calls to the primary call-answering center, in response to a determination that none of the first, the second, and the third limits have been exceeded;

the step of commanding the call-routing node to not route calls to the primary call-answering center comprises the step of

commanding the call-routing node to cease to route the calls to the primary call-answering center, in response to a determination that the first and the second limits have both been exceeded;

the step of routing calls to the primary call-answering center comprises the step of

in response to the command to commence, routing the calls from the call-routing node to the primary call-answering center; and

the step of routing the calls to the alternate call-answering center comprises the step of

in response to the command to cease, routing the calls from the call-routing node to the alternate call-answering center.

20. A method of controlling the call-load experienced by a call-answering center, comprising the steps of:

automatically periodically checking parameters of call-answering performance of a primary call-answering center while the primary call-answering center is in service, to determine at the primary call-answering center from the parameters whether a call that has not yet been routed to the primary call-answering center is likely to be answered within a predetermined period of time if it were routed to the primary call-answering center;

in response to a determination that the call is unlikely to be answered within the predetermined period of time, the primary call-answering center commanding a call-routing arrangement for routing calls to call-answering centers to not route calls to the primary call-answering center;

in response to absence of the command, the call-routing arrangement routing calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to the primary call-answering center; and

in response to the command, the call-routing arrangement routing the calls that have not yet been routed to a call-answering center and are destined for the primary call-answering center, to an alternate call-answering center.

21. The method of claim 20 wherein

the step of checking parameters comprises the steps of

determining whether a predetermined percentage of calls most recently answered by the primary call-answering center have each been answered within a predetermined first time limit,

determining whether any call waiting to be answered by the primary call-answering center has been waiting longer than a predetermined second time limit, and

determining whether a number of calls waiting to be answered by the primary call-answering center exceeds a predetermined third number limit;

the method further comprises the step of

commanding the call-routing arrangement to commence to route the calls to the primary call-answering center, in response to a determination that none of the first, the second, and the third limits have been exceeded;

the step of commanding the call-routing arrangement to not route calls to the primary call-answering center includes the step of

commanding the call-routing arrangement to cease to route the calls to the primary call-answering center, in response to a determination that the first and the second limits have both been exceeded;

the step of routing calls to the primary call-answering center comprises the step of

in response to the command to commence, the call-routing arrangement routing the calls to the primary call-answering center; and

the step of routing the calls to the alternate call-answering center comprises the step of

in response to the command to cease, the call-routing arrangement routing the calls to the alternate call-answering center.

22. A method of controlling a call load of a call-answering center that has a signaling connection to a call-routing node which connection, when activated, causes the routing node to reroute calls destined for the call-answering center to an alternate call-answering center, comprising the steps of:

automatically periodically determining in the call-answering center whether a call routed to the center while the center is in service is likely to be answered within a predetermined period of time,

automatically ensuring deactivation in the call-answering center of the signaling connection to cause calls that have not yet been routed to the center to be routed to the center, in response to each determination that the call is likely to be answered within the predetermined period of time; and

automatically ensuring activation in the call-answering center of the signaling connection to cause calls that have not yet been routed to the center to be routed to an alternate call-answering center, in response to each determination that the call is not likely to be answered within the predetermined period of time.

23. The method of claim 22 wherein the step of determining comprises the step of:

automatically periodically checking parameters of call-answering performance of the center while the center is in service to determine from the parameters whether a call routed to the center is likely to be answered within a predetermined period of time.

24. The method of claim 22 for a center that has a queue for calls waiting to be answered by the center, wherein

the step of determining comprises the steps of

determining whether a predetermined percentage of calls most recently answered by the center have each been answered within a predetermined first time limit,

determining whether any call waiting in the queue has been waiting longer than a predetermined second time limit, and

determining whether a number of calls waiting in the queue exceeds a predetermined third number limit;

the step of ensuring deactivation of the signaling connection is performed in response to determinations that none of the first, the second, and the third limits have been exceeded; and

the step of ensuring activation of the signaling connection is performed in response to determinations that the first and the second limits have both been exceeded.

25. The method of claim 22 for a center that has a queue for calls that have been routed to and are waiting to be answered by the center, wherein the signaling connection while active causes calls not yet routed to the center to be routed from the node directly to an alternate call-answering center, and causes calls already routed to the center to remain routed from the node to the center.

26. The method of claim 22 wherein

the step of ensuring deactivation comprises the steps of

maintaining deactivated the signaling connection when it is not active, and

deactivating the signaling connection when it is active;

and

the step of ensuring activation comprises the steps of

maintaining activated the signaling connection when it is active, and

activating the signaling connection when it is not active.

27. The method of claim 22 for an emergency-call-answering center wherein calls routed to the center are emergency calls.