US Patent 7929993 Multi-SIM-based mobile device

A mobile device includes first identification circuitry and second identification circuitry. The first identification circuitry is associated with a first network and the second identification circuitry is associated with a second network. The mobile device simultaneously registers itself with the first and second networks using the first and second identification circuitry, respectively. The first and second identification circuitry may each comprise subscriber identity modules. The mobile devices handle outgoing and incoming calls based on user preferences. The user may override the preferences for selected calls.