Hi!

Legally, during crew rest, you can receive one phone call from your company, and you are not allowed to do ANY company business. A 2nd phone call from the company breaks your rest, and you have to start your 10 hours all over again.

Also, On Call is NOT rest, BUT, according to FAA practices, you can be on call 24/7, and, so, obviously, have 0 rest before a flight. It is not technically LEGAL, but it is allowed by the FAA in actual practice, much like many Part 91companies can fly their plane Part 135 for-hire, as the FAA allows it.

cliff
GRB