In this article a problem of signal propagation in nerve fiber is considered. Ohm’s losses and heat processes are taken into account. These permit to join two stages (metabolic and non-metabolic) of propagation and Na+ and K+ ions transmission through cell membrane connected with propagation. Electrodynamics of nerve fiber is described by telegraph equations with losses. Heat processes in fiber are described by an equation of entropy transfer. Ion motion at metabolic stage against the electro-chemical potential is described by negative conductance, responsible for the escape flow.