FIELD: communications. SUBSTANCE: given communication system KV has communication equipment and testing equipment TV. Communication equipment has aggregate of telephones from T1 to Tn, aggregate of communication lines and at least one transmitting station to send signals in system of telephone communication KV. Testing equipment TV includes central signal processing facility ZV which sends testing commands and converter WV connected to programmable signal processing unit S that is built to convert digital test signals generated by programmable signal processing unit S under control of test commands to working signals, interruption unit UV connected to converter WV and designed to interrupt depending on working signals, single communication line as minimum for time period determined by working signals. With their assistance changes of signal based on systematic interruptions in telephone communication system about which it can be signaled by way of comparison with variation of corresponding reference signal are conducted. EFFECT: enhanced operational reliability of communication system. 19 cl, 12 dwg
