Alternate destination call redirection for telecommunications systems
First Claim
1. A method for routing a call through a public switched network, comprising a plurality of switching systems interconnected in said network, to one of a plurality of destinations, containing:
- responsive to receiving said call in an ingress switching system of said public switched network, querying a data base shared by a plurality of switching systems of said network to obtain a routing indication;
responsive to receiving a routing indication from said data base, extending said call via another switching system of said network and via an egress switching system of said network toward one of said destinations;
after extending said call to said another switching system and in the absence of receipt of an answer indication on said call, determining in said another switching system whether said call can be further extended toward said one destination;
responsive to a determination that said call can be so extended, further extending said call toward said one destination;
responsive to a determination that said call cannot be so extended, generating and transmitting from said another switching system to said ingress switching system a message comprising an indicating that said call cannot be completed to said one destination; and
responsive to receiving said message in said ingress switching system, accessing, in said ingress switching system, alternative routing data related to said routing indication for extending said call from said ingress switching system toward another of said destinations.
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Accused Products
Abstract
This invention relates to apparatus and methods for redirecting calls from a first choice destination to some alternate destination if the call cannot be conveniently completed to the first destination. A call is initially extended through a toll network toward the first destination; if the toll network is congested and cannot reach an egress switch to access the first destination, or if a local exchange network connecting the first destination to the toll network is congested, or if a first destination PBX cannot be reached from the toll or local network because all access channels thereto are blocked, or if the first destination PBX is congested or attendants are unavailable, an indication that the call cannot be completed to the first destination is sent back to the ingress switch to the toll network for that call. The call is then redirected from the ingress switch of the toll network to an alternate destination. In some cases, this alternate destination may be the same as the first destination but accessed from a different egress switch of the toll network. Advantageously, this arrangement allows calls to be completed to an alternate destination regardless of the reason why the call cannot be completed to the first choice destination. If the first choice destination is a program-controlled PBX, the PBX can be programmed to reject certain types of calls according to the traffic load being handled by the PBX and the particular staffing available at a certain time. Thus, for example, the PBX could be arranged to accept calls for new orders but to redirect calls requesting information about shipments if the staffing of the first choice destination is relatively low. The reason for rejection can be used for altering the choice of an alternate destination or for canceling a potential redirection.
104 Citations
22 Claims
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1. A method for routing a call through a public switched network, comprising a plurality of switching systems interconnected in said network, to one of a plurality of destinations, containing:
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responsive to receiving said call in an ingress switching system of said public switched network, querying a data base shared by a plurality of switching systems of said network to obtain a routing indication; responsive to receiving a routing indication from said data base, extending said call via another switching system of said network and via an egress switching system of said network toward one of said destinations; after extending said call to said another switching system and in the absence of receipt of an answer indication on said call, determining in said another switching system whether said call can be further extended toward said one destination; responsive to a determination that said call can be so extended, further extending said call toward said one destination; responsive to a determination that said call cannot be so extended, generating and transmitting from said another switching system to said ingress switching system a message comprising an indicating that said call cannot be completed to said one destination; and responsive to receiving said message in said ingress switching system, accessing, in said ingress switching system, alternative routing data related to said routing indication for extending said call from said ingress switching system toward another of said destinations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22)
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20. In an interexchange carrier network comprising a plurality of switching systems, apparatus for routing a call to one of a plurality of destinations, comprising:
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an ingress switching system comprising processor means responsive, under program control, to an incoming call destined for said destination for querying a data base shared by a plurality of said switching systems of said network to obtain a routing indication from a database means for said call; said processor means responsive, under program control, to receipt of said routing indication for extending said call through another switching system of said network toward said one destination via a first of two egress switching systems of said network connected to said destination; and said processor means further responsive, under program control, and in the absence of receipt of an answer indication for said call, to a data message comprising an indication, received from said another switching system, that said call cannot be completed to said destination via said first egress switching system, for accessing, in said ingress switching system, alternative routing data related to said routing indication for extending said call toward said one destination via the second of said two egress switching systems.
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Specification