At+t Corp.

Margaret A Burd

Margaret H Redberg

Michael M Winseck, Jr

Steven F Knittel

Steven T Heinsius

Rise J Frankel

Barbara Patrice Havens

William G Kuchenbecker

Benny J Ellis

Arnold Chester McQuaide, Jr

Timothy J Lefoley

Janice A Jones

Jeremy R Hutt

Jennifer T Fitzgerald

Judith L Sherman

Gary J Mayer

A fault-tolerant call-processing adjunct processor comprises a redundant, duplicated, service unit provisioning and maintenance processor), a duplicated LAN connected to both service units, and plurality of served units (voice-processing processors) each connected to both LANs. Each service unit and each served unit has a duplicate copy of mission-critical information (customer records and commands). Both service units are continuously exercised by operating in an active-active configuration. The service units alternate the use of the LANs, thereby continuously exercising both LANs and providing independent duplicate sources of the mission-critical information to the served units. All sending units rely on having their mission-critical communications timely acknowledged by all receiving units. Served units retry with the other service unit those communications that failed with a preferred service unit. All units store failed communications for subsequent retry. Served units either send communications (alarms) to both service units, or rely on service units to exchange communications (call measurements) received from the served units, to ensure that both service units are in possession of the same information.

Fault-tolerant processing system architecture

Calls made to an 800 service subscriber are routed to the subscriber's primary location via a telephone network switch operating in conjunction with a specially configured adjunct processor. The adjunct processor is arranged to monitor the call even after it is answered by an attendant or other subscriber personnel at the primary location. If the call is to be redirected from the primary location to an alternate location, the adjunct is signaled, typically by a DTMF sequence. The adjunct responds by putting the calling party on hold and by initiating a call to the alternate location on an outgoing trunk of the network switch, in such a way that it emulates or imitates both the routing (call treatment) and billing the characteristics of a call made from the original customer location. Redirection can then be completed in one of three ways: blind transfer, consultation, or conference. Billing for the call is arranged so that the subscriber of the 800 number originally dialed by the calling party at the customer location pays only for the portion of the call in which the primary location is actively involved in communications with the calling party. The subscriber providing the 800 number for the alternate location pays for the portion of the call in which the alternate location is involved, as though the call originated from the customer's location and proceeded directly to the alternate location, without having been rerouted at the network switch. Thus, the subscriber is not charged for any period of time which is not 'used' by that subscriber.