Abstract:
An Internet Protocol (IP) telephony system comprises a radio communications interface and a processor. The processor is configured to execute a Communications over Internet Protocol (CoIP) application for an Internet Protocol (IP) telecommunication service; obtain an indication of a change of a Subscriber Identity Module (SIM) card of the mobile telephony device; and upon obtaining the indication of change, and generate, for sending over the radio communications interface, a registration message to the IP telecommunication service, the registration message including a new International Mobile Subscriber Identity (IMSI) for the mobile telephony device.