A Guide to 911

What is 9-1-1?  When should I call?  What happens when I dial 9-1-1?  I hope to answer these questions and more on this page, so the residents of Sherborn, and others, will have a better idea of what happens when they press 9-1-1 on their phones.

A Brief History

To understand what happens when you dial 9-1-1 you should understand why the 9-1-1 system was developed.  In the early days of telephone use in the United States, up to the 1960's, every County, City, or Town could have a different phone number to dial in the case of emergency.  It was also likely that a different phone number would need to be dialed depending on what type of emergency you had.  Police, Fire, and Medical services might all be reached by dialing different phone numbers.

In 1957 the National Association of Fire Chiefs recommended a single number be chosen to be used in reporting fires nationwide.  The suggestion was that no matter where you were, a single number would connect you to that area's local fire department, thus saving time in an emergency.  It wasn't until 1967, ten years later, that the Presidents Commission on Law Enforcement and Administration of Justice recommended a single number that could be used to report ALL emergencies.

The responsibility fell on the Federal Communication Commission (FCC) who met with AT&T in November of 1967 to come up with a solution.  It was necessary to have a number that was simple to remember, easy to dial in an emergency, and that would not be easily mis-dialed.  9-1-1 made sense, as they were on opposite ends of the rotary dial, at that time the common phone.

Today, in over 93% of locations in the United States and Canada, dialing "911" from any telephone will link the caller to an emergency dispatch center (information provided from Wikipedia.com).

So what happens when I dial "911" in Sherborn?

Sherborn uses a system called e911 (Enhanced 9-1-1), a system that has become a standard in Massachusetts, and in most of the country.  When you dial 911 from any land line phone in Sherborn, your call should be routed directly to the Sherborn Police Department, who can then dispatch the proper Police, Fire, or Medical Response.  The system has built in redundancies, so if there was a problem with the Sherborn 911 system, the call would be forwarded to a sister-department, in our case, the Dover Police Department.  

When the call is answered, the e911 system provides the call taker with what is called ANI (Automatic Number Identification) and ALI (Automatic Location Identification)information, when available.  This information provides dispatch with the phone number, and location of the calling party, however one of the first questions asked by the call-taker will be where the emergency is taking place.

Why am I being asked where the emergency is if you already have the information?

The MOST important thing to know in an emergency (for both the caller and the call-taker) is WHERE the emergency is taking place.  With a location, the Sherborn Police Department can at least start a response, and call in, or call off other units/departments as is necessary.

Say you're talking to a friend from across town on the phone, and they tell you they are having chest pain, then the line goes silent.  You dial 911 and tell the officer your friend is having a heart attack.  The information displayed at the Sherborn Police Department is the information associated with the phone YOU are calling from.  Knowing the address of the emergency saves valuable time in an emergency, and greatly increases the response time of rescue personnel.

Why do all 911 calls go to the Police Station?

It is important for all emergency calls to go to a single Public Safety Answering Point (PSAP) in a jurisdiction so employees can be trained in how to best handle the calls, and the response.  In Sherborn, ALL Police Officers are certified to operate the e911 system, and are capable of dispatching Police, Fire, and EMS.  Beyond that, the Police Department can request services from, Advanced Life Support (should the Fire Department request it), Med-Flight, even local utilities or the Highway Department.

When should I dial 911?

You should dial 9-1-1 to report a fire, any type of medial situation, crimes in progress, or any type of suspicious activity. We ask that you do not use it to report a lost/found dog, power outages, or request school closing info.  The Sherborn Police Department responds to ALL 9-1-1 Calls, including hang-ups and mis-dials.

What should I know when calling 911?

The information needed depends on the emergency, but the most important things the call taker will want to know are WHERE the emergency is, WHAT the emergency is, and CALLER INFORMATION.  Caller Information is asked for in case a follow up call, or other information is needed.  A name and phone number where you can be reached could be invaluable in an emergency.  The Sherborn Police Department will respond to a anonymous call, but providing as much information as possible will only aide us in providing the proper response.

What happens if I dial 911 from a cell phone?

In Massachusetts, if you dial 911 from a cellphone, the call first goes to one of three Massachusetts State Police PSAP's.  The majority of those calls go to the MSP's Framingham PSAP which handles between 3,000 to 5,000 a day.  There, the call-taker receives the ANI and ALI information described above, and with newer wireless phones, an APPROXIMATE location of the caller.  The State Police call-taker will ask you for information such as your location, the nature of the emergency, and callback information.  The call will then be transfered to the necessary PSAP (Sherborn PD for example).  This means you will most likely be asked the same information twice.  It's important for the State Police PSAP to know the details of the call in case the caller were to get disconnected during the call.

You should be prepared when you dial 911, especially when calling from a cell phone.  The quicker you can provide accurate and necessary information to the State Police PSAP, the faster they can transfer you to the local PSAP.  Click HERE for more information provided by the state.

Can using a Voive Over Internet Protocol (VOIP) connection change the information sent when I dail 911?

HERE is what the FCC has to say on that subject, probably the best source of information for this question.  If you have a VOIP service, you should check with your 911 provider on how exactly your 911 settings are set up. 

HEREis how Comcast has addressed the issue with their Digital Voice Service.

Can I place a test 911 call?

911 can be test dialed to ensure the proper ANI and ALI information are being transmitted, or to show a child what to expect when dialing 911, PROVIDED the Police Department is aware of the test call PRIOR to dialing 911.  You should call the Police Station at (508) 653-2424 and provide your name, address, phone number and reason for wanting to place the test call.  The Desk Officer will tell you either to place the test call, or to call back, if it is not a convenient time to do the test.

computer screen

This is the e911 system in it's normal operating state.  This is one of the two actual systems located in the dispatch area of the Sherborn Police Station..

computer screen

Here is the system displaying ANI and ALI information.  This information is displayed (if available) when the call is answered and remains on the screen until removed by the officer.

computer screen

Here you see a close-up of the ALI tab, which is displaying both the ANI and ALI information for the Sherborn Police Station.  You see the calling number (ANI) and the address (ALI) provided..


Below are larger images of both the main display, and the mapping screen.

computer screen

computer screen