Stopwatch clock

Electronic or quartz clock that can synchronize your move when the time signal broadcast or specific radio stations, as well as (for ultra precise time) satellite GPS.
Network master clock

Network master stopwatch clock system designed to provide the exact time a wide range of customers in the cities, factories, etc. It consists of one primary and several secondary clocks and communication lines.

Primary watches are designed for precise timing and its transmission to the secondary clock.

Previously represented the astronomical clock or timepiece, where instead of the shooter was electro-mechanical unit forming teams at the secondary clock, in the simplest case - provides circuit circuit every minute.

Now, with the development of electronics and telecommunications - digital clock accuracy class with multiple channels introducing amendments.

Slave clocks are used to display the time in the master clock networks.

Previously represented a gear without the engine controller and the second hand, minute hand moved from the solenoid pulses of alternating polarity voltage of 27 volts on the primary clock, the hour - through gear 1:12 [source not specified 819 days].

Now - cheap independent quartz watches with a clock from the primary may also directly by radio signals exact time, in some cases - GPS.