We have obtained the various types of I‐V characteristics measured experimentally and in analog simulations, by merely changing the junction and the microwave parameters within the same resistively shunted junction model with purely sinusoidal current‐phase relation. It was found that the subharmonic steps do exist in the limit &bgr;c→0, though they can have finite rounding without thermal noise. The statistical properties of the ’’chaotic’’ solutions wer e discussed and their effective temperature was defined and calculated.