Patent ID: 8346301

Claim:
A calling method comprising: receiving, by a Home Location Register (HLR) of a roaming prepaid subscriber, a update location message from a Visited Mobile Switching Centre (VMSC) of the roaming prepaid subscriber; sending, by the HLR, an Insert Subscriber Data (ISD) message to the VMSC; obtaining, by a service platform, subscription information of the roaming prepaid subscriber from the ISD message; modifying, by the service platform, a Service Control Point (SCP) address contained in the subscription information to the address of the service platform; sending, by the service platform, the modified subscription information to the VMSC; receiving, by the VMSC, a call to a called subscriber initiated by the roaming prepaid subscriber; triggering, by the VMSC, the call to the service platform according to the address of the service platform; receiving, by the service platform, the call; determining from the call that the roaming prepaid subscriber has activated a callback service; and instructing, by the service platform, the VMSC to release the call, and instructing a call connection device to connect the roaming prepaid subscriber to the called subscriber.