In 1887, shortly after the invention of the telephone, the Russian inventor K.A Mościcki put forward the idea of a PaBX relay and developed a station structure with six phone numbers – an automatic central switch, which, in essence, is a precursor to the automatic telephone exchanges of today. Of course, in the modern sense, he was far from the PaBX: switching connections on the station, although performed without a telephone lady, were made by the subscribers themsleves.
The caller would send a 'call signal' through the station to another party. This signal was fed to all telephones included in this station. Hearing their call signal, the called party had to move the switch to the desired position and push their button to inform the caller that they were ready to start a conversation. Both parties would then lift their handsets from their respective cradles. Only then would all other potential 'line subscribers' be disconnected. .
The invention of K.A. Mościcki did not solve the problem of the need to automate a telephone system for a large number of telephone subscribers. But it is a clear indication that the automation of the telephone community was already evident in the early stages of the development of telephony.
K.A. Mościcki's idea to automate telephone connections via one relay began to develop much later. The initial efforts of inventors focused on developing stepper and machine selectors.