On the question of classification of electrical digital line signals

This paper explains about the electrical digital line signals which are the primary component of the unified network of electrical communications. Moreover, in some regions of West and East Siberia, and Baikal land, digital intrazonal and local primary networks, including xDSL networks, are functioning, basically, with using electrical digital line paths. In this connnection the actual issue is the choosing of the most efficient digital line signals for transportation in the standard digital PDH streams over the existing electrical digital line paths. The most efficient line signal type possesses noise-immunity, longer regeneration section, low cost etc.