  We show that the mixing effect of the neutral gauge bosons in the 3-3-1-1
model comes from two sources. The first one is due to the 3-3-1-1 gauge
symmetry breaking as usual, whereas the second one results from the kinetic
mixing between the gauge bosons of U(1)_X and U(1)_N groups, which are used to
determine the electric charge and baryon minus lepton numbers, respectively.
Such mixings modify the \rho-parameter and the known couplings of Z with
fermions. The constraints that arise from flavor-changing neutral currents due
to the gauge boson mixings and non-universal fermion generations are also
given.
