Communications Division: What is 9-1-1?
9-1-1 is a three digit number anyone can dial on the telephone to get help when there is a life threatening emergency.
When you call 9-1-1, a professionally trained person called a "dispatcher" answers the phone. The dispatcher asks what the emergency is and sends help to you, such as the police, fire department, ambulance, highway patrol, or Coast Guard. If you are not sure whether there is a real emergency, it is better to be safe and call 9-1-1.

You can call 9-1-1 anytime there is an emergency from telephones in California and many part of the United States. The call is free from all telephones, including pay phones.
When Is It Appropriate to Call 9-1-1?
You should call 9-1-1 for any situation where an IMMEDIATE police, fire, or medical response is necessary to protect lives or property. Here are some examples:
•     When an ambulance is needed 
•     When there is a fire 
•     When there is a crime in progress or a crime has just occurred,        especially if the suspects might still be in the area
•     When a vehicle accident is being reported, especially if there might
       be injuries
•     When a prowler or suspicious person is being reported
When NOT to Call 9-1-1
Do not call 9-1-1 for road and travel or severe weather information, for repair information on household appliances, for complaints of excessive noise, for complaints about littering, for pets up a tree, or for legal advice, etc.
Please, DO NOT call 9-1-1 for any situation where you do not need help RIGHT AWAY TO PROTECT LIFE OR PROPERTY. If you call 9-1-1 when you don't have an emergency, you will not receive help any faster.
What to Expect When You Call 9-1-1
When you dial 9-1-1, you may hear a recording asking you to stay on the line and wait for the dispatcher to answer. We know seconds can seem like minutes when you need help, but PLEASE DO NOT HANG UP; STAY ON THE LINE.
When the dispatcher answers, explain what the problem is. For example: My house is on fire, Someone has been shot, I need an ambulance, Someone just got their purse snatched, etc.
Try to remain calm. We know it's difficult. Taking a deep breath and letting it out slowly will help.
The dispatcher will ask you questions to help determine what service you need such as police, fire, or paramedics and to further identify the problem. Yes, the questions are important, and we do have to ask them in order to provide you with the best possible service.
Some of the Who, What, When, and Where questions you will be asked:
We need to know where to send help, so the dispatcher may ask, Where are you? Where is the emergency? or What is your address/location?
What happened?
Did you see who did it? Can you describe the suspects?
When did this happen?