The counter ST 4-9 corresponds the mechanism with electromechanical principle of action with the microelectric motor operating gears with the figures put on them. As a rule, it is established in the device of the account of consumption of hot and cold water. At water course through the device of remote reading of signal (reed switch contact), impulses which arrive to the counter are formed and put in action movement of gear with the least numerical weight (red colour).

At remote reading of output signal in place of course of water it is established the impeller which will transform water course to rotation of constant magnet. The impeller rotates constant magnet which closes contact passing by reed switch, forming impulse which is passed by wires to the counter defining the account of consumption of hot and cold water.

The device of remote reading of signal (reed switch contact) gives out on cable in circuit one impulse on certain quantity of litres of water. Presence of such device allows to make the centralised account of water consumption and to take readings in hard-to-reach spots, such as wells. Counters with remote reading of output signal transmit signal to the counter by means of read switch and the impeller with constant magnet.