Patent ID: 11909777
Assignee: WONE SAGL
Field: Digital communication (Electrical engineering)
Classification: CPC H | IPC H

Claim 13:
14. Method for initiating a mobile voice call from a caller user equipment (UE) to a callee UE, comprising the following steps:
a) providing to the caller UE a software function arranged to execute on or from the caller UE;
b) the caller, using said software function, selecting a callee phone number compliant with the phone number recommendation E.164;
c) the caller UE communicating, to a session initiation protocol (SIP) server, the callee phone number;
d) the SIP server (41) determining whether or not the callee phone number is associated with a callee UE for voice over internet protocol (VOIP);
e) if so, the SIP server identifying the callee UE using a SIP address the “user” field of which comprises the callee phone number, initiating the call between the caller UE and the callee UE as a VOIP call; and
f) if not, the SIP server initiating the call between the caller UE and the callee UE as a circuit switch (CS) call using the callee phone number and using a network switching function of a first network to which the callee UE subscribes.