Hi guys! R1 admit here...best of luck for all the R2 folks!
From previous experience:
Not everyone will receive a call - whether you're admitted or not. If you're offered a scholarship, you will most likely get a call. Some people will find out via portal and not over the phone so don't fret if you don't get a call.
They make all their calls throughout the day and then release all decisions on the portal at the end of the day. If you're dinged or waitlisted you won't find out until then (generally after 3:30 or 4pm CST).
International students generally will not receive a phone call due to time difference.
Everyone who is admitted gets a letter with details and an admit gift in the mail shortly after (international students may get an email notification that a package is coming).
Try not to obsess throughout the day - distract yourself. I know it's easier said than done. The GMATclub live chat is a nice way to interact, make jokes, and help the day go by faster.
Can't wait to meet all my fellow classmates in July!