Transitions are boolean conditions that permit or deny entrance to the connecting state machine. As mentioned above, each state machine has an activity function associated with it which encompasses a specific behavior. Inputs provide a means for supplying external parameters to a state machine and are analogous to function parameters, whereas local variables provide static storage within the state machine. Buttons and dials are explained below. Communication in HCSM occurs through the use of buttons and dials and is a one-way correspondence from the world outside the state machine to the state machine itself.
Dials provide more leeway in their use.
Each dial contains a data slot that can be set with information that the HCSM may use in computing its output. It is important to note that in both mechanisms, the HCSM is not forced to regard the information and must determine the appropriateness of the message. This ability to direct the agent plays an important part in building scenarios.