Patent ID: 6192239
Filing Date: 2001-02-20
Classification: H04W

Abstract:
In a portable telephone handset capable of functioning within a plurality of operating networks respectively operating under different standards, a method of handing an active telephone call over between networks to maintain the integrity of the call, the method comprising the steps of:monitoring at least one signal parameter corresponding to a first operating network during a first active telephone call on the first operating network between a user of the portable handset and another party, the user of the handset or the other party being the calling party;producing a warning message if the at least one signal parameter is not within a predetermined acceptable range, the step of producing a warning message comprising requesting both the user of the handset and the other party to hang up;determining a telephone number corresponding to the other party if the telephone number can be accessed; andsubsequent to both the user of the portable handset and the other party hanging up, initializing a second active telephone call from the portable handset to the other party on a second operating network if the telephone number corresponding to the other party can be accessed.