Abstract: In the occurrence of a multi-mode portable handset leaving the coverage area of a first operating network during an active telephone call on the first operating network, a method is disclosed for terminating the telephone call and re-initiating it within a second operating network. The signal strength and bit error rate corresponding to the first operating network are monitored during the telephone call. When it is determined that the handset is leaving the coverage area using these indicators, the handset warns both parties in the conversation. With use of the redial function or CLID (Calling Line Identification) the telephone number of the party other than the user of the portable handset is determined. The handset proceeds to terminate the call on the first operating network and dials the telephone number corresponding to the other party on the second operating network. The telephone conversation can then proceed on the second operating network with a minimum inconvenience to the user of the handset.