i have run on an ambulance for almost eight years. Some credential requirements vary from state to state, but almost everyone in EMS now follows National Standards.
EMS = Emergency Medical Services
EMT = Emergency Medical Technician
There are different levels of EMT certification/licensure. Paramedic is the highest level. Levels included:
EMT-D (defibrillator certified)
All EMT's are state licensed, and most are nationally certified/registered/licensed too. A Paramedic is one of the LEVELS of EMT.
Some states allow company training programs. Most require college programs. But where you receive your training does not determine your level.
Each level requires additional classroom hours, clinical hours, and continuing education requirements. Each level must take State Boards (which are now National Standards), and the test is both written and 'practical'. Practical meaning you must demonstrate your 'hands on' skills in various scenarios. Like Nursing Boards, most of the testing is based on the 'best right answer'.
Each level marks an increase in an ability to do invasive/sterile procedures and push certain types of drugs. For example: An EMT-B can push Epinephrine, Albuterol, Oxygen--basics. When you get to Paramedic level you can push narcotics, etc.
Tying in EMS and Fire Dept. are one of those variants from community to community. In some areas, members of the Police Department are also required to be EMS certified. Some ambulance companies are affiliated with hospitals, others with cities or towns, others are private. I work for a private company that the city hires to handle their emergency care.
In Michigan, the level of care you receive on an ambulance is based on the Ambulance's certification, not the personnel's. So if the ambulance is certified 'Basic', even a Paramedic on board may only practice "Basic" procedures.
And just an added note. I've seen Third Watch, E.R., and the various 'Paramedic' programs on Discover Health. None of them really get it right. The closest to reality I've ever seen (although it's the dark side) was the movie "Bringing Out the Dead" with Nicholas Cage.
Hope this helps! Kavi