As a general rule, National Registry will get you "in the door" - as to whether or not the states will automatically grant you a ticket or not is up to them, but usually they'll at least let you sit with proctor for a license exam.
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With Paramedic, it's a little different, since you're operating "directly" under the license of a physician (for ALS skills and meds), each Emergency Medical System is run by it's own MD - called the Project Medical Director.
Think of the old mideaval days where each guy with a castle was "king" as far as his army reached. That's the way thie fiefdom of EMS's are around the country today.
Some PMD's are awesome - former .mil, or at least agressive trauma huntin' shoot-n-scoot white stuff on red stuff guys. Then there are the original PMD's - back in the "Johnny and Roy" days right after the White Paper, when the emphasis was on rapid cardiac care. They don't know BTLS from DKNY, and are more concerned with getting a SAMPLE hx than the fact that you were getting shot at. But as they retire, the gung-ho guys are moving in.
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