In fast ion conductors, the dynamics of the hopping motion of the mobile ions determines the shape of their hopping conductivity spectra. Therefore, analysis of complete conductivity spectra is a useful tool for extracting details of the correlated and relaxational hopping behaviour of the ions. The paper shows how this is done on the basis of the jump relaxation model. Furthermore, the model is reconsidered and extended, with a view to describe not only crystalline but also glassy electrolytes.