  The current-voltage characteristic (CVC) of break junction made from
polycrystalline Bi_{1.8}Pb_{0.3}Sr_{1.9}Ca_2Cu_3O_x is investigated. The
experimental CVC has hysteretic feature that reflects a part of a curve with
negative differential resistance. The CVC is discussed within the framework of
the Kummel-Gunsenheimer-Nicolsky theory considering multiple Andreev
reflections in superconductor/normal-metal/superconductor junctions.
