Patent ID: 7139588

Claim:
A method of switching a communication mode to voice communication in response to a voice communication request during data communication in a mobile station (MS), comprising the steps of: (a) allowing a calling party's MS to make a call connection request by attempting to connect a call to a mobile switching center (MSC) over an access channel so that the calling party's MS can make voice communication with a called party's MS; (b) allowing the MSC to make a call connection processing request by determining a communication state of the called party's MS and requesting a mobile carrier (MC) to execute call connection processing on the basis of the communication state; and (c) allowing the MC to carry out a communication process by transmitting a voice communication request message containing a phone number of the calling party's MS to the called party's MS in data communication through a short message service (SMS) system. (d) allowing the MC to carry out a response information reception operation by receiving a response to the voice communication request message from the called party's MS; (e) allowing the MC to make a voice communication switching request by requesting the MSC to switch a communication mode to voice communication when the response from the called party's MS is an approval of the voice communication connection; (f) allowing the MSC to carry out a data communication idle process by switching the data communication in progress to an idle state in response to the voice communication switching request from the MC and transferring a data communication termination command to the called party's MS and an interworking function (IWF); and (g) allowing the MSC to carry out a voice communication process by requesting the called party's MS to receive the voice communication over a paging channel, receiving a response thereof from the called party's MS over an access channel, and processing the voice communication between the calling party's MS and the called party's MS over a traffic channel.