Patent ID: 7869406

Claim:
A handover method of establishing a call from a synchronous modem unit of a Dual Band Dual Mode (DBDM) mobile communication terminal with a synchronous mobile communications system while the mobile communications terminal is in a connected state with an asynchronous mobile communications system via an asynchronous modem unit of the mobile communications terminal, and while the synchronous modem unit is in an idle state, the handover method comprising the steps of: the asynchronous mobile communication system requesting the synchronous mobile communication system to switch a connection environment of the mobile communication terminal to a synchronous environment, a Mobile Switching Center (MSC) of the synchronous mobile communication system requesting a Base Transceiver System (BTS) of the synchronous mobile communication system to transmit a paging signal; the BTS transmitting the paging signal to the synchronous modem unit; the synchronous modem unit receiving the paging signal, transitioning to an active state based on the received paging signal, and transmitting a paging response signal to the BTS; and establishing a call between the synchronous modem unit and the synchronous mobile communication system; and releasing the connection between the asynchronous modem unit and the asynchronous mobile communication system.