  We have investigated constraints on the coupling between dark matter and the
interacting Chaplygin gas. Our results indicate that the coupling constant $c$
between these two entities can take arbitrary values, which can be either
positive or negative, thus giving arbitrary freedom to the inter-conversion
between Chaplygin gas and dark matter. Thus our results indicate that the
restriction $0<c<1$ on the coupling constant occurs as a very special case. Our
analysis also supports the existence of phantom energy under certain conditions
on the coupling constant.
