百達翡麗，集成電子子母鐘系統，配六層鐘塔，約1975年製

During the 1970s, Patek Philippe perfected its electronic master clock timing system and they were considered the most state of the art and accurate systems available on the market. The master timing system consisted of a highly accurate master clock with numerous ‘slave’ timepieces. Airports, train stations, and office buildings employed these timing systems to ensure that exact time was uniformly displayed. The systems were extremely accurate and featured solid-state master clocks with no moving parts (except for the hands, of course) and were designed to be protected from water, vapor, fumes and salt spray. An almost limitless number of slave clocks could be connected to the master clock, making it ideal for a multitude of locations, including hospitals, shops, laboratories and power stations.