my company had customer base from PR to HI. customers were registered by zip code. contact by correct time was pretty easy, as zip codes get larger as they go west.
the time here is 8:37am DC time.(it is a well known fact that DC is now the center of the universe).
i find it interesting on some of these posts that people ask how to do something when they are arriving at the airport at 7:05.???? and want to know how to get somewhere, and how long will it take.