Based on a wide range of literature and sources, the author of the article aims to analyze the main problems that have emerged in the course of modernization of Soviet telephone communication during the two five-year periods of the era of "developed socialism" (1970s). Among such important technical, technological and economic problems, the author, in particular, emphasizes the problem of the heterogeneity of telephone communication technology, the issue of optimal planning of telephone construction in economic regions and the rational distribution of financial and material resources, the problem of improving exploitation and enhancement efficiency of telephone networks. As a solution of these problems, a number of measures were proposed. Therefore, to overcome the diversity of technical telephone communication devices, it was proposed to speed up the development of electronic and quasi-electronic automatic telephone stations. The planning of the development of telephone networks was carried out from the position of achieving the maximum efficiency of capital investments and expansion of subscriber services. To improve productivity in the operation of telephone systems, progressive-statistical and program-corrected (qualitative) methods were introduced. Solving the problem of payback of telephone communication provided for the selection of an economical and reliable accounting system. Despite these problems, the technological modernization of Soviet telephone communication was in line with global trends. In the 1970s in the domestic electro-communications was discovered a new direction in the creation of multi-channel communication systems - a time-division channel. This led to the creation of pulse-code modulation systems. Progress was also observed in the field of telephone communication automation. At the same time, the efficiency of the operation of telephone facilities increased: the networks were equipped with new test facility, measuring instruments, etc. At the same time, the extensive growth of telephone communication continued, and the rate of commissioning of new capacities increased year by year. However, the author emphasizes that despite the shortage of telephone communication in the country, the technical capacity of the telephone network was often not fully used. Mass housing construction in cities often did not correspond to plans for telephone construction, as a result of which many residential areas remained without a telephone connection for a long time. District centers and workers' settlements were also slowly telephoned. In general, the growth of telephone capacity did not keep pace with the growing needs of the economy and the population of the country. As a result, none of the telephone communication problems was completely solved during the Soviet period. Despite the fact that during this period almost all telephone equipment in the country was modernized, the chronic technological gap was not overcome.
