  We study the charge current transmitted through the correlated quantum dot
characterized by a finite magnitude of the Coulomb interaction |U|. At low
temperatures the correlations can lead to appearance of the spin (for U>0) or
charge (for U<0) Kondo states qualitatively affecting the transport properties.
We explore an influence of the charge Kondo effect on the electron pair
tunneling introducing the auxiliary two-component model which describes the
fluctuations between empty and doubly occupied states of the quantum dot.
