Master Clock System

A master clock is a precision clock that provides timing signals to synchronize slave clocks as part of a clock network. The master clock in such installations is controlled by an accurate quartz crystal oscillator, usually referenced to an external frequency standard which is part of a world-wide timekeeping system.

Thousands of such clocks were installed, in schools, offices, railway networks, telephone exchanges and factories all over the world; they resembled along case, but had a very robust mechanism and a less ornate case. The devices driven could be wall clocks, tower clocks, factory sirens, school bells and occasionally clock chiming mechanisms