A switch device is provided that selectively enables the utility of a processing device. In one example, the processing device is a microprocessor operating in a target device, such as a computer system, and the switch device is a radio frequency controller device that sets the switch responsive to an RF signal. The processing device only operates when: 1) the processing device is installed in the expected target device; and 2) the switch has been activated, for example, using the RF signal. The radio frequency controller device has a switch that is set to a defined state responsive to the RF signal. Conditional logic circuitry may use the RF signal to determine if the switch should be activated, and sets the state of the switch accordingly. The radio frequency controller device operates a data processing process only when the switch is activated. A processing device sends data to the radio frequency controller device, and if the switch is active, the processing device receives modified data in response. The processing device also generates expected data, and compares the expected data to the modified data. If the expected data matches the modified data, then the processing device is allowed to operate.