A telemetry unit is provided for mounting inside a pneumatic tyre. Specifically, the controller of the present invention retrieves hardware and controller commands from memory based on one or more instructions received from the CPU. A test selects an action corresponding to the current state of the computer system; executes the test program which performs the selected action; determines the state of the computer system after the test program has executed; and compares the determined state to the state indicated in the state table as the target state to the selected action on the source state.