Abstract: A mobile telephone switching office for switching telephone calls among landline subscribers and mobile subscribers, the office controlling the call origination, termination and release of call from both the landline and the mobile subscribers, and providing a separation between the elements associated with each function for regulatory purposes. The mobile telephone switching office includes a time slot interchange mobile switch network for switching voice information among landline and mobile subscribers. A call control processor controls the switch network. Calls with a mobile subscriber are controlled by the cell site through a serving area controller, which transfers control messages between one or more cell sites to which it is connected and the call control processor. The serving area controller maintains records of the mobile voice channels available through the cell sites connected to it and the mobile calls taking place at any given time.