Originally Posted by johnso29

This has always been my understanding. If someone knows this to be wrong, please correct me.

Your SC is 12 hours in duration. The end time is simply the end of your SC (3 hours notice to departure) period. While SC is not considered duty, it is also not rest. You must be able to look 24 hours back from your release and find 8 hours free from duty. Therefore, if you're assigned a trip off SC your release time for tomorrow should not exceed 16 hours from the beginning of your SC.

Example-SC starts @ 0600. At 1700 scheduling calls you for a 2030 departure. You're scheduled to arrive @ 2230. Look back 24 hours & you don't have your 8 hours(SC started @ 0600 so you only had 7.5 hours) You can't do the assignment.