In the article, based on computer simulation in Matlab 7.0 Simulink environment, a model of noise-resistant coding (NC) system was developed, which works on the basis of the algorithm of parallel-cascade high-precision coding and iterative decoding. A comparative analysis of the energy gain G (dB) high-precision iterative algorithm with Gray coding algorithm is made. The results of modeling in Simulink error-correcting code and an iterative high-precision Gray code in digital transmission of information.