Technique for returning to directory assistance or information services provider upon command

Abstract From the Canadian patent

A cellular telephone subscriber who wishes directory assist nce services is connected in the conventional manner to an operator who identifies a destination teleptone number desired by the subscriber- As in the prior art the operator then initiates a call con~~cting the subscriber to the destination telephone number. However rather than dropping all further involvement with the call the preferred embodiment of the present invention continually monitors the connection thereby established for a predetermined DTMF signal issued by the customer such as that obtained by pressing the "*" button. If such a signal is detected the customer is transferred back to a directory assistance operator who …