Bromate-sulfite-ferrocyanide reaction operated in the CSTR is sensitive to small but supercritical additions of either acid or base. When operated at two different kinds of steady states, this dynamical feature gives rise to activatory or inhibitory excitability. Spontaneous periodic oscillations are also sensitive to such perturbations. Periodically repeated pulse additions elicit a pattern of excitatory or oscillatory spikes that depends on the period and amplitude of the perturbations. These firing patterns are characterized by firing number defined as an average number of firings per a forcing period. Experiments with periodically pulsed additions of H+, OH-, and SO32- provide one-parameter and two-parameter firing diagrams. Recently, a detailed model has been formulated; using this model, we study global dynamics of the response by calculating firing diagrams under conditions corresponding to experiments. The experimental results are compared with calculations.