Nine-one-one is only to be used in emergency situations. An emergency is any situation that requires immediate assistance from the police/sheriff department or the fire department or an ambulance. If you are ever in doubt you should call 9-1-1.  It's better to be safe and let the 9-1-1 call taker get you emergency assistance if needed.  

 Do not call 9-1-1:

• for information
• for directory assistance
• when you're bored and just want to talk
• for paying traffic tickets
• for your pet
• as a prank

If you call 9-1-1 by mistake, do not hang up. Tell the call taker what happened so they know there really isn't an emergency.

How do I make a 9-1-1 call?

• In an emergency, dial 9-1-1 on your phone. It's a free call. You can use any kind of phone: push button, rotary, cellular, cordless, or pay phone. (With some pay phones, you may need a coins to get a dial tone; with wireless phones, Enhanced 9-1-1 does not yet work.)
• Stay calm and state your emergency
• Speak loudly and clearly. Give the 9-1-1 call taker your name, phone number and address where help is needed.
• Answer the call taker's questions. Stay on the telephone if it's safe to do so, and don't hang up until the call taker tells you to.

What if a 9-1-1 caller doesn't speak English?

When necessary, a 9-1-1 call taker can add an interpreter from an outside service to the line. A non-English speaking caller may hear a short conversation in English and some clicking sounds as the interpreter is added to the line.

What if a 9-1-1 caller is Deaf, or hearing/speech impaired?

Communications centers that answer 9-1-1 calls have special text telephones for responding to 9-1-1 calls from Deaf or hearing/speech impaired callers.

• If a caller uses a TTY/TDD, the caller should:
• Stay calm, place the phone receiver in the TTY, dial 9-1-1.
• After the call is answered, press the TTY keys several times. This may help shorten the time necessary to respond to the call.
• Give the call taker time to connect their TTY. If necessary, press the TTY keys again. The 9-1-1 call taker should answer and type "GA" for Go Ahead.
• Tell what is needed -police, fire department, or ambulance. Give your name, phone number and the address where help is needed.
• Stay on the telephone if it is safe. Answer the call takers questions.

If a Deaf or hearing/speech impaired caller doesn't have a TTY/TDD, the caller should call 9-1-1 and don't hang up. Not hanging up leaves the line open. With most 9-1-1 calls,

The caller's address is displayed on the call taker's screen and help will be sent.

Source of Information provided by 9-1-1.