  Conductance of submicron constrictions of PbTe:Bi was studied up to 8T and
between 4.2K and 50mK. The structures were fabricated by electron beam
lithography and chemical etching of high--electron mobility films grown by MBE
on BaF_2. In the moderately strong magnetic fields perpendicular to the
current, B>1T, the conductance shows accurate quantization in the units of
1e^2/h as a function of the side-gate voltage. In the absence of the field, a
temperature-independent step structure, with an average step height approx.
1e^2/h, is observed. It is suggested that such a quantization may reflect the
lifting of the Kramers degeneracy by the exchange interaction among the
electrons, effective despite a large dielectric constant of bulk PbTe.
