  In this paper we study the Fourier coefficients of theta functions attached
to Dirichlet characters at cusps other than infinity. The method is based on
expressing them in terms of explicit elements of the adelic Schwartz space and
studying the action of the adelic metaplectic group on these elements. We
derive explicit formulae for the Fourier coefficients at all cusps. For the
sake of simplicity, some restrictions are placed on the Dirichlet characters
considered.
