VoIP and Cell Phones to Call 9-1-1

Prince George’s County Public Safety Communications 9-1-1 Center receives ever-911 Communicationsincreasing numbers of 9-1-1 calls from cellular telephones. Close to 70% of the 9-1-1 calls are from wireless telephones.

While the Public Safety Communications has technology that will help the call taker identify the location of a wireless call to within approximately 300 feet, this technology may be limited by other factors. These limitations may prevent the    9-1-1 call taker from locating the caller, so it is very important to know your exact location in the event of an emergency.

Make it a habit to note addresses, intersections and mile markers to identify where you are should you need to call      9-1-1.

If your cellular call is routed to an incorrect jurisdiction due to tower site locations, your call will be transferred to the appropriate 9-1-1 center. When this occurs, be prepared to provide location and incident information to the 9-1-1 call taker at the new 9-1-1 center. Be patient, while the call taker works to gather the necessary information to send you the help you need.

There is also an increase in the use of Voice of Internet Protocol (VoIP) telephone services to call 9-1-1. The portable nature of VoIP raises a number of challenges for the 9-1-1 Centers and the emergency services community.

Unlike traditional phone services, when a caller dials  9-1-1 from a VoIP phone, address and call back number information is not automatically provided to the 9-1-1 Center.

Although VoIP service providers are making progress in overcoming the differences between VoIP and traditional phone services, some difference remain when calling 9-1-1:

voip 911
  • VoIP 9-1-1 calls may not connect to the appropriate 9-1-1 Center, or may improperly ring to the a phone number that is not staffed by 9-1-1 call takers
  • VoIP 9-1-1 calls may connect to the correct 9-1-1 Center, but not automatically transmit the user’s phone number and/or location information
  • VoIP customers may need to provide location or other information to their VoIP providers, and update this information if they change locations, for their VoIP 9-1-1 service to function properly
  • VoIP service may not work during a power outage, or when the Internet connection fails
  • Make sure you have backup batteries or a backup power source for your VoIP phone system.
  • Review our Helpful Hints Brochures for more information on VoIP Phones and Wireless Phones