In this paper we use data from extensive measurements, which are implemented in telecommunication networks of electric power industries in the six countries. The model of digital telecommunication channel and the model of hypothetical signaling CCS No7 channel under the influence of bursty errors are presented in the paper. These models can express very accurately data and signaling transmission in the digital telecommunication network (TN) of the Serbian Electric Power Industry (SEPI). We consider the model of digital and signaling channel first and after that analyze the availability of these channels under the influence of bursty errors.