Maximal ideal space of a commutative coefficient algebra

The basic notion of the article is a pair (A,U), where A is a commutative C*-algebra and U is a partial isometry such that mapping U()U* is an endomorphism of A and UU belongs to A. We give a description of the maximal ideal space of the smallest coefficient C-algebra of the algebra C*(A,U) generated by the system (A,U).