External Module 9200-0521C can be added externally to most ATS Clocks, Displays and Master Clocks. A plug-in power module and data cable are provided. The Ethernet Cable must be ordered separately. Before using Option 521C or 9200-0521C the Local Time Zone setting is required. A rotary switch selects the time zone, and jumpers select DST, and 12/24 Hour format. Once installed the device will query an SNTP Server via your internet approximately every 10 minutes. After acquiring Coordinated time and date it will update the ATS device every minute at the 30th second.