Abstract: Redirection of calls from a busy primary destination to a secondary destination of a switched egress alternate destination redirection (ADR) customer is performed in the absence of sufficient terminating line status information in the form of either a busy or free indication being provided to the originating switch which provides the ADR service feature capability. The originating switch infers that the primary destination is busy and redirects the call to the secondary destination accordingly if the time that passes since the inception of the call is greater than a predetermined interval in which the call has not been answered.

Abstract: 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.