A method to merge telephony services over a circuit switched network (3) and a packet switched data network (4), in a mobile phone terminal, comprises the steps of: receiving communication events arriving via a circuit switched network (3), receiving communication events arriving via a packet switched data network (4), storing communication events into a shared memory, and analyzing communication events arriving via the circuit switched network (3) and communication events arriving the via the packet switched data network (4), and then routing each communication event to a voice application, either directly or via said means for storing, in order to store it temporarily, so that all the events concerning a same call are synchronized when they are received by said voice application.