  We report unexpected features of the transport in the dielectric spin density
wave (SDW) phase of the quasi one-dimensional compound (TMTSF)_2PF_6: the
resistance exhibits a maximum and a subsequent strong drop as temperature
decreases below approximately 2K. The maximum in R(T) is not caused by
depinning or Joule heating of the SDW. The characteristic temperature of the
R(T) maximum and the scaling behavior of the resistance at different magnetic
fields B evidence that the non-monotonic R(T) dependence has an origin
different from the one known for the quantum Hall effect region of the phase
diagram. We also found that the borderline T_0(B,P) which divides the field
induced SDW region of the P-B-T phase diagram into the hysteresis and
non-hysteresis domains, terminates in the N=1 sub-phase; the borderline has
thus no extension to the SDW N=0 phase.
