The ABRO example, presented in the following figure, is a typical example which contains the main elements of SyncCharts. It combines instantaneous signal reaction, preemption and concurrency. It has three input signals A, B, and R and an output signal O. Initially, the states ABRO, WaitAB, wA, and wB are activated. The program waits for signals A and B. If A is present, the weak abort transition between the states wA and dA is crossed and the final state dA is activated. In parallel, if B is present, the weak abort transition between the states wB and dB is crossed and the final state dB is activated. As soon as dA and dB are active, the normal termination transition between WaitAB and done is crossed by emitting the signal O. The signal R (Reset) is a priority signal. If R is present, the strong abortion transition between the macrostate ABO and itself is crossed that preemptively returns the system to the initial state.