Scattering problem for Neumann Laplacean with a continuous potential on a domain with a smooth boundary and few semiinfinite wires attached to it is studied. In resonance case when the Fermi level inthe wires coincides with some {it resonance} energy level in the domain the approximate formula for the transmission coefficient from one wire to another is derived: inthe case of weak interaction between the domain and the wires the transmission coefficient is proportional to the product of values of the corresponding resonance eigenfunction of inner problem at the points of contact.