Pulse method of watchdog device building for subscriber telephone lines control

Abstract

The problems of information security in modern world are becoming increasingly important. One of the main sources of threats is the contact connections to the subscriber telephone lines (STL) in the telephone networks of technical intelligence communication devices. Aim: The aim of this work is the presentation of the new pulse method of unauthorized connections identification to the STL, description of implementation and principle of operation of the watchdog control device. Materials and Methods: The method consists in analysis of response to pulse excitation of two second-order oscillating systems. The connection of telephone wiretap causes unbalancing of signals in oscillatory circuits and this certifies the existence of the bug. Results: The structure and functions of the watchdog based on presented method is described. This device consists of two parts – analyzer and blocker allocated at the opposite sides of the controlled STL. The variant of implementation of the pulse linear analyzer and channel of signals processing is considered in details.