Always tell them to dial "nine-one-one", never refer to this emergency number as "nine-eleven". There is no such number as "eleven" on the telephone and a child may easily become confused in the process of dialing.
Teach your children to trust the 911 operator - explain to them that 911 is their friend and a source of help to them during an emergency.
Teach your children their home address, phone number, and full name.
Advise your children about any possible emergency situation likely to occur at your home or location. Explain what things to look out for.
If a member of the family has a medical condition, tell your children how to identify these symptoms, i.e., person not breathing or suddenly collapsing, etc.
Instruct the child to call 911 should these symptoms occur.
Carefully explain to your children that 911 is for an emergency and that an emergency is when they need to get law enforcement, the fire department or paramedics in a hurry.
Also explain that 911 is not a toy or a game and should never be played with unless it is actually needed.
Teach your child if they "accidentally dial 911" do not hang up. If you hang up, we will send a police officer to your home to make sure everything is alright.
Possibly use the classic "Crying Wolf" story and relate it to the use of 911. However, at the same time you must avoid discouraging a child from using 911. Any time that they think they need to call, encourage them to use 911, even if they are in doubt.
For more information on teaching children about 911 please visit 911 for Kids.