To solve the current issues of detecting seismoelectric signals at preparing earthquakes, a hardware-software complex was created, designed to study the telluric current variation in the ultra-low frequency range (0-20 Hz), which is installed in the seismically active region of the Zailiysky Alatau (Northern Tien Shan) near the foci of the Vernensky M7.3 and Keminsky M8.2 catastrophic earthquakes. Special mathematical algorithms and program tools were designed for continuous registration, real-time data analysis, and visualization of the information on telluric current. It was proposed an effective system for reducing the influence of stray currents on the measuring equipment, an optimal lightning protection scheme, and a grounding system for the power supply devices, which allow uninterrupted measurements in mountain conditions even in time of close intensive thunderstorm. The capabilities of the hardware-software complex make it possible to detect both the weak electric signals with an amplitude of several tens–hundred of microvolts only, and intensive electromagnetic pulses from close lightnings without the damage of registering apparatus. In the records of telluric current the wave oscillations were detected which belong to the frequency range of the Pc2–Pc4 class micropulsations of the geomagnetic field. Perspectives of the detection of seismogenic electrical signals in variations of telluric current on the eve and during earthquakes are connected with data obtained during the earthquake of magnitude MPV 4.5, which occurred on July 1, 2021 at 60.4 km from the measuring point. At the time of the earthquake, immediately after the main shock, in conditions of good weather and low industrial noise, using the calculation of the dynamic power spectrum of the telluric current in the frequency range 0.2 Hz - 0.0282 Hz, electrical signals were detected, presumably of seismogenic origin.