E911 and VoIP - What You Need To Know


When considering switching to a Voice over Internet Protocol (VoIP) service for your home there are some important differences that you should be aware of with respect to 911 and Enhanced 911(E911) emergency services dialing. This article provides a brief description of what 911/E911 is and how it works, followed by a discussion on the limitations of VoIP, and what the future holds.


What is E911 Service

It’s a good bet that almost everyone knows what 911 is and what it is used for. From an early age children are made aware of this number and its meaning. For completeness, 911 is a number that you dial for emergency services in North America (police, fire, or medical emergency services). The idea of a 3 digit number specifically used for emergency services was first introduced in the UK in the 1930’s (where 999 is used). It was in the late 1960’s that the number 911 was introduced and implemented in the United States, with Canada following suit soon after.

When 911 is dialed you are connected to an emergency service provider, know as Public Safety Answering Point, or PSAP. The PSAP you are connected with depends on where you are dialing from. In most cases you will be connected with a local emergency service provider. Once connected you can talk to a person and explain the emergency situation. They can then respond to your emergency request by dispatching the appropriate services.

Enhanced 911 services takes this one step further by providing your phone number and location information (physical address based on the phone number from which the call was made) when the call arrives at the PSAP. This is particularly useful in instances such as the caller is unable to speak or the call is from a visitor who is unsure of the exact location. The location information is pulled from databases maintained by the various local telephone companies. The phone number of the caller is used to map to the correct address information in the database (known as Automatic Location Identification, or ALI). There are some privacy and other technical nuances to this system but they are considered to be out of the scope of this document. This section is only intended to give some background to how the system works so we can understand the main differences when using a VoIP phone service. For more detailed information on these systems refer to the resources provided at the end of this article.

Fast Forward 3 Decades and Enter VoIP

When VoIP was in its infancy in the early 2000's there was no requirement for the service to provide 911 dialing. Some of this was due to the developmental state of the technology and also to help promote industry growth and competition. However, that all changed in 2005 when the FCC (Federal Communications Commission) ruled that all "interconnected" (meaning that the service connects to the Public Switched Telephone Network, or PSTN) VoIP services must be compliant with new E911 obligations. This ruling included the requirement for each provider to notify customers and consumers of its 911 limitations (discussed below). Note that other VoIP services that are not considered "interconnected", such as PC to PC services like Skype and Google Voice, do not have to comply with this ruling. Both Skype and Google Voice currently do NOT support E911 dialing.

E911 VoIP Limitations to Consider

As we mentioned above there are some important differences in the way VoIP works and how that affects the 911 services compared to the traditional Plain Old Telephone System (POTS):

  1. You must REGISTER your location information: When signing up for service YOU are responsible for registering your location and activating your E911 “feature”. Register the location where you will use the service (see point 2 below to understand the importance of this step). This is typically not a huge deal as most home users will utilize their phone service from their house in most cases. Note that most providers charge a small monthly E911 fee for this service, which covers regulatory fees and administrative costs. The E911 fee is typically in the $1 per month range (e.g. Phone Power is $0.99/month).
  2. Portability: One of the many benefits of VoIP is being able to take your ATA (telephone adapter) and plug it into any high speed internet connection to get your phone service. However, this is the worst situation for an E911 system that grabs your location information from a database that is based on a phone number. You MUST be aware that your location information will be based on what you provided on sign up. If you decide to visit your mother-in-law in a different state and take your ATA with you the location information provided to the PSAP will be the location you provided on sign up (i.e. most likely your home address). This is important to understand as the call will be directed to a LOCAL emergency service based on the phone number (and NOT where you are calling from). This can be overcome by making sure you plan ahead and update your location information appropriately.
  3. Power outages: Your VoIP ATA (and Internet modem, router etc.) requires electricity to work. If the power goes out so does your phone service. You MUST understand that in this situation you will not be able to dial the emergency services via your phone service. To overcome this concern you can utilize UPS (uninterruptable power supply) battery backup devices or generators. If you have a cell phone then this may not be a big concern, unless it is a possibility that someone could be left in the house who does not have access to a cell phone (maybe a younger child or an elderly family member).
  4. Internet outages or call blocking: VoIP technology sends your phone calls over your Internet connection. If that connection is down, or if your Internet company blocks calls for some reason then you will NOT be able to dial 911 via your phone service. A large portion of the North American population has cells phones now which can be a way to remove this concern, leading to the next point.
  5. Alternative arrangements: Considering some of the above points should make you realize that you cannot guarantee that you will have 911 access in all possible scenarios. We highly recommend that you consider alternative arrangements in case of an emergency situation. As mentioned above, cell phones can be a good alternative. Other users may consider keeping a stripped down bare bones landline service for emergency and alarm system needs.
  6. Make sure visitors to your home know about these limitations: You should always inform visitors regarding the limitations of 911 service with your phone service, as outlined above. For example, if you have a relative come to stay for a longer period of time or who may be looking after your kids while you are at work or out. Most service providers will supply stickers explaining this for you to put on your telephones as reminders.
  7. Potential delays compared with landlines: There is also one other item that should be mentioned here. As many VoIP providers route your call through 3rd party networks there is a chance that a call can take longer to connect when compared with a traditional landline.

We recommend that before signing up for a provider you check their notification on the services limitations. Here is a table illustrating the differences between VoIP and a regular landline using POTS.

Scenario VoIP Landline
Do I have to register my location information with my provider? YES NO
Can I dial 911 during power outages in case of an emergency? NO YES
Can I dial 911 during Internet outages in case of an emergency? NO YES
Do I need to inform longer term visitors about E911 dialing limitations YES NO

The Future with VoIP and E911

Even though there have been issues and limitations with integrating VoIP into existing E911 services there could be a role reversal in the future. The inherent features and benefits associated with VoIP can be used to improve E911 service. A lot of research and development has been going into this area with a particular focus on the business sector, such as:

  • E911 management for large IP-PBX installations,
  • tracking of IP phones as they change locations within a corporate network,
  • real time location updates directly through IP phones (great for telecommuters or remote office workers), and
  • call management features such as recording emergency calls and routing to on-site security.


Understanding the differences between E911 dialing with VoIP when compared with a traditional landline service (POTS) is important. Since the FCC ruling in 2005 the VoIP industry has worked hard to improve E911 services through their systems and are continuing to make improvements. As of June 2012 the FCC reported that 32.5 Million residential connections were "interconnected" VoIP, a staggering 40% of all residential connections in the USA. PSAP's could eventually all have data connection options which may allow VoIP providers to connect directly (via an Internet connection). In the future there may be more information that can be passed and features such as call recording utilized to help improve the services.

Until then we recommend that you make sure you have alternative arrangements available when you make the switch. Here are some reminders for you:

  • REGISTER the location where you will be using your Home service. Make sure you activate the E911 service also, if required.
  • If you TRAVEL with your ATA, make sure you update your location to where you will be using the phone service. Note that you may have to do this in advance.
  • Consider a UPS (battery backup) device or a generator if your location experiences power outages.
  • Have a back up arrangement in case your Internet connection goes down. This could be a cell phone, or a bare bone landline service as examples.
  • Remember that services like Skype and Google Voice do NOT support E911 dialing services.

For more in-depth information and further reading, including its history and greater detail on how it works, we recommend the 911 and Enhanced 911 wikipedia articles

Published by WhichVoIP

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WhichVoIP Visitor Comments

#3 : Posted by Richard

When dialing an emergency call using voip, do you dial "911" or "E911" I've never seen any information on the dialing procedure. Thank you

-> Response: You just dial 911 the same as you would on a landline. It's just it gets handled slightly differently behind the scenes when it is Internet based.


#2 : Posted by Louis Moorman

Looking to activate 911, what do I do?

-> Response: You will need to contact your provider directly to activate your 911 service and provide your address.


#1 : Posted by Jeremy

In the above you mention updating your location information if you take your adaptor with you to a different location. Is that simple to do and what is involved? Thinking of switching to VoIP and did not know about this. Thanks!

-> Response: Good question Jeremy. Yes, it is easy to do and most providers allow you to make the updates inside their online portal. You can also phone CS and ask them to make the change. Note though that you can only register one location for a phone line at any one time. Hope this helps.


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