On any output line from an agent an Inhibitor node may be present. This node allows another agent to inhibit the output of an agent for a specific time period. Each processor board had several input and output lines along with corresponding control lines, these transmitted 24 bit messages at 280 baud. A reset line initialises each finite state machine to some predefined starting condition. The building of real robots that interacted with the real-world brought out some deficiencies with the subsumption architecture, these were mainly the result of trying to manage large collections of subsumption agents and synchronisation.
Behaviours also exhibit inhibition and suppression but only by other behaviours.
Registers and monostables defined within a behaviour are not viewable outside of the behaviour they are defined in, however their values may be passed by messages between behaviours. Registers within a behaviour are sometimes used as an excitation indicator. The subsumption architecture works.