  Some features of a program 'eett6f' for top quark pair production and decay
into six fermions at linear colliders are discussed. Lowest order standard
model predictions for cross sections of some six fermion channels and for the
top quark decay width are confronted with the predictions obtained within a
model with an anomalous Wtb coupling. The question of wether non doubly
resonant background can easily be reduced by imposing kinematical cuts is
addressed.
