How 9-1-1 Works

Although every system is unique, a 9-1-1 system works primarily in thefollowing way:

  • the three digit emergency number 9-1-1 is dialed
  • the call is answered at a Public Safety Answering Point (PSAP)
  • the trained telecommunicator at the PSAP receives the emergency information from the caller
  • the telecommunicator dispatches the appropriate agency (police, fire EMS) to the emergency

If people dial 9-1-1 in an area not served with a 9-1-1 system, they shouldreceive a telephone intercept that will notify them that they do not have 9-1-1service and that they should hang up and dial the appropriate seven-digitemergency number, or dial “0” for the operator. There are urban/ruralareas that use a fast busy signal instead of the intercept. Some territories are9-1-1 capable, but are not served by a 9-1-1 PSAP. This is usually due to anemergency agency not wanting to participate in the system. Instead, they usetheir own seven digit emergency number. The PSAP, upon receipt of the call, willnotify the appropriate agency of the call, even though they do not serve thatemergency agency.

The Benefits of 9-1-1

The major benefits of 9-1-1 to citizens and public safety agencies should beunderstood by those involved in the planning and implementation of 9-1-1systems. The means by which 9-1-1 provides this benefit is primarily by savingtime in the overall response of a public safety agency.

The total time required in response to a perceived emergency is the sum of:

  1. Time from citizen perception of an emergency situation to the time he or she reaches the correct public safety agency;
  2. Time from receipt of a call by the agency to the time an emergency service vehicle is dispatched to the scene of the emergency;
  3. Time from the dispatch of the vehicle to the time it arrives at the scene of the emergency. A 9-1-1 system can save valuable minutes in that initial period of time when reaching the appropriate emergency agency can mean life or death.

A number of surveys have been conducted on the problems citizens have inreaching their public safety agencies. These surveys showed that fewer than 50%of the citizens knew the telephone numbers of their own public safety agencies,and when citizens are traveling, very few would know the appropriate agencies,much less the emergency telephone numbers of those agencies. Citizens who didnot know the correct emergency telephone number relied on telephone books ordirect calls (dial “0”) to telephone company operators.

Telephone operators have historically provided citizens with assistancethrough dial “0” service. However, these operators are not highlytrained in emergency service requirements and they must search the telephonedirectories for the number to the correct agency. An additional complicationwith the use of the telephone operator for emergencies is the gradual reductionof the number of operator centers, which has been caused by the automation oftelephone switching centers. An operator reached through dialing “0”in an emergency could be located more than 200 miles from the caller, and wouldtherefore be ill-equipped to assist the citizen in selecting the correct agency.

Average call delays for citizens not knowing the correct number ranged from1.0 to 3.5 minutes, depending upon the agency type and the number of agenciescontacted before the correct agency was reached. A full 20% of the citizenssurveyed had an average delay of 3.5 minutes because of failure to reach thecorrect agency on the first contact. Additionally, 10% of these citizens neededassistance from more than one type of agency.

These long delays in citizen access to public safety agencies are caused bycitizen confusion about agency identification and the lack of easily locatedemergency number. By using 9-1-1 as a universal emergency number, both of theseproblem areas will be eliminated. The three-digit number is easily remembered,and trained answering personnel can quickly identify the correct agency andprovide for the transfer of the emergency information to that agency.

The benefits of reduced response times by emergency service agencies arequite clear. A study of the President’s Commission on Law Enforcement showed adirect relationship between apprehension of criminals and low response time. Areduction of an average of only one minute in fire response time could probablysave millions of dollars annually in any state. Finally, a reduction in responsetime for ambulance and rescue units will reduce the death rate in heart attack,injury accident and other life and death medical emergencies. An important butsomewhat less visible benefit of 9-1-1 is the more efficient, morecost-effective, use of scarce emergency service resources for the publicbenefit.

Back to NENA Home Page