Eastern Daylight Time and Central Daylight Time are exactly 1 hour apart. The terms refer to US Time Zones which are adjacent.
Boston, New York, Washington DC, and Atlanta are in the Eastern Time...
The central time zone (CST) is not ahead of eastern time zone (EST). The eastern time zone is one hour ahead of the central time zone. So if it is 9:00 AM CST, it is 10 AM EST.