DSC Tech Library
This section of our technical library presents information and documentation relating to Emergency Broadcasting Systems and Disaster Recovery Applications.
Should an emergency arise in your community, our 911 broadcast service can deliver large volumes of calls quickly using thousands of phone lines simultaneously. In the event of a blizzard, wild fire or devastating flood, your community can be notified quickly given specific instructions if an evacuation is required using our emergency broadcasting service. If a dangerous chemical spill occurs in your community, you can target specific areas to call. If a severe snow storm hits your area, your community can be notified of school closings or event cancellations.
The following article relates to emergency broadcasting and how it is used in various communities today. This information was obtained from the internet with attribution to the author and/or community.
Communicating During Emergencies
FCC - Federal Communications Commission - fcc.gov
During emergencies - local, state, and national - the importance of our
country's telecommunications and broadcast systems becomes clear. We use
our phones to call 911 or to call our family members to make sure they
are safe; we turn on our televisions and radios to get information
While there is no doubt that our country has one of
the world's most extensive and dependable telecommunications and
broadcast systems, unusual conditions can put a strain on them.
The following information will help you better
understand what happens within the telecommunications and broadcast
systems during an emergency and how best to use these systems during a
crisis or disaster.
Emergency Communications Components
There are three main components to emergency communications:
911 telephone call processing and delivery through the Public
Safety Answering Points (PSAP) and wireless call dispatch;
the Emergency Alert System; and
radio and/or broadcast or cable television station news and
All of these components must operate effectively in order to achieve
a successful response to an emergency.
Emergency personnel and others often learn about
emergencies through 911 calls. 911 is the official national emergency
number in the United States and Canada. Dialing 911 quickly connects you
to a PSAP dispatcher trained to route your call to local emergency
medical, fire, and law enforcement agencies.
The 911 network is a vital part of our nation's
emergency response and disaster preparedness system. Upgrades in this
network to provide emergency help more quickly and effectively are
constantly being made. For example, most wireline 911 systems now
automatically report to the PSAP the telephone number and location of
calls, a capability called "Enhanced 911" or "E911."
By receiving the telephone number of the caller, the PSAP is able to
call back in the event the call gets disconnected. The PSAP is also able
to determine the location of the caller by cross-referencing the
telephone number against a location database. Wireline E911 is available
in most parts of the country.
While wireless phones can be an important public
safety tool, they also create unique challenges for public safety
personnel. Since wireless phones are by their very nature mobile, they
are not associated with one fixed location or address.
In an effort to increase the ability of emergency
personnel to respond to wireless 911 calls, the Federal Communications
Commission (FCC) has adopted rules requiring wireless telephone carriers
to provide E911.
Wireless carriers have begun to deploy technologies
to meet the FCC's E911 rules. When fully implemented, wireless E911 will
provide information about the location of consumers dialing 911 from
mobile phones. However, since wireless E911 will not be available
everywhere immediately, it is important for consumers to follow a few
basic steps when calling 911 from their mobile phone:
If your wireless phone is not
"initialized" (i.e., you do not have a contract for
service with a wireless service provider), and your emergency call
gets disconnected, you must call the emergency operator back because
he or she does not have your telephone number and cannot contact
To help public safety personnel allocate
emergency resources, learn and use the designated number in your
state for highway accidents or other non-life-threatening incidents.
Often, states reserve specific numbers for these types of incidents.
For example, "#77" is the number used for highway
accidents in Virginia. The number to call for non-life-threatening
incidents in your state can be found in the front of your phone
Using TTYs to Dial 911
At the present time, wireline phones and analog
wireless phones can transmit 911 calls to PSAPs from callers using text
telephone devices (TTYs). The FCC encourages TTY users to call 911
directly for immediate service. However, if TTY users choose to contact
a PSAP via Telecommunications Relay Service (TRS), TRS centers will need
to forward the TTY caller's phone number to the PSAP, delaying
transmission of this information to the PSAP.
Wireless service providers have made technological
changes to their networks to provide TTY compatibility for digital
wireless calls for consumers with select TTY-compatible handsets.
However, in certain locations TTY users may not be able to complete 911
calls successfully to 911 emergency call centers using these newly
available digital wireless services. The Commission is encouraging
public safety organizations, vendors of TTY equipment for 911 call
centers, TTY vendors, and wireless service providers to work together
both to better identify the extent of these difficulties and to develop
solutions. In the meantime, TTY users should consider such alternatives
for placing an emergency 911 call as landline phone service, analog
wireless service, or TRS.
Public Safety Answering Point and
Wireless Call Dispatch
The emergency dispatcher uses location information
to direct public safety personnel responding to the emergency to ensure
the shortest possible emergency response time.
At the PSAP, the operator verifies the caller's
location, determines the nature of the emergency, and decides which
emergency response teams should be notified. Sometimes a single primary
PSAP will answer for an entire region. In most cases, the caller is then
transferred to a secondary PSAP from which help will be sent. Secondary
PSAPs are sometimes located at fire dispatch offices, municipal police
headquarters, or ambulance dispatch centers. Communities that don't have
PSAPs rely on public safety emergency operators and communications
centers to process emergency calls.
Once the call is processed, the PSAP operator or
dispatch center alerts the appropriate emergency response team. During
emergencies, radio systems frequently are used by emergency units and
officers at the scene to coordinate activities among all emergency
personnel - fire, rescue, police, dispatchers, etc. - with the emergency
units on their way and with dispatchers at command bases.
Network Damage and Black-outs
If the telecommunications network is damaged in a
disaster, your wireline or wireless phone and text pager may not work.
If only your electricity goes out (a "black-out"), your
telephone may still work. In a black-out, you still may be able to use
your wireline phone because electricity and telephone transmissions
travel on different wires. If you keep the battery on your wireless
phone and text pager fully charged, you should be able to use these,
too, in a black-out.
Text pagers have a built-in radio
transmitter/receiver. Messages are transmitted over the wireless
network, a nationwide network of radio towers that transmit data. Some
text pagers can subscribe to the National Oceanic and Atmospheric
Administration's (NOAA) National Weather Service for any weather alerts.
Why E-mail May Work When Phone Lines
Don't During a Natural Disaster or State of Emergency
When a telephone call is completed on the public
telephone network, transmission circuits are assigned and dedicated
between the two users for the length of the call. The telephone network
is engineered so that during normal usage there are adequate facilities
that can be assigned and dedicated to handle the number of calls during
the peak period. However, if during a disaster or emergency the number
of calls exceeds that peak (or if the network transmission capacity is
reduced), then some calls will be blocked. And, of course, if the phone
being called is already in use, the call will certainly be blocked.
The Internet backbone uses shared rather than
dedicated transmission facilities so that even during heavy usage the
Internet will work, albeit perhaps more slowly. Cable modem and DSL
users who have dedicated Internet access can generally get through to
their e-mail systems, although dial-up Internet users may experience
some blocking when they try to dial their Internet Service Provider
(ISP), either because the local telephone system is congested or all the
ISPs' lines are busy. E-mail itself is an Internet application which has
the additional characteristic that the recipient doesn't have to be
available at the same time as the sender, and instead can connect to his
or her own mail system at his or her convenience to retrieve messages
that have been delivered there.
The Emergency Alert System/Radio and
In the event of an emergency, many people stay
tuned to local radio and/or television stations to receive updates on
what is happening and what to do.
There is a nationwide broadcast system in place for
national disaster or other large-scale disasters. The Emergency Alert
System (EAS) provides not only the President, but national, state, and
local authorities with the ability to give emergency information to the
general public via broadcast, cable, and wireless cable systems.
All broadcast stations and cable systems are
required to broadcast emergency alerts and messages for national
security emergencies initiated by the President. Broadcast stations and
cable systems are not required to broadcast EAS alerts and messages
initiated by state and local authorities, but the FCC encourages
broadcast licensees and cable operators to transmit emergency alerts as
a public service. Information about local natural disasters is often
broadcast via EAS.
All EAS broadcasts should be accessible by audio
and visual means, or simple visual means, including closed-captioning,
open-captioning, crawls or scrolls.
Exception: If your local television/radio tower or
studio is damaged during a natural disaster like a tornado, you may not
receive the signal.
Accessibility of Emergency
Because broadcast stations and cable systems are
not required to broadcast EAS alerts and messages initiated by state and
local authorities, the FCC has separate requirements to meet the needs
of persons with disabilities in cases of local emergencies. The FCC
requires that any information that is intended to further the protection
of life, health, safety, or property, such as immediate weather
situations, civil disorders, evacuation orders, school closings, relief
assistance, etc., be accessible to persons with disabilities. These
rules apply to all local broadcasters, cable operators, and satellite
television service providers. There are no exemptions to these rules and
they apply any time emergency information is provided. Critical details
about the emergency must be provided in a visual format, such as open
captions, scrolls, or even hand-lettered signs. The critical details
must also be provided in an aural format. If crawls or scrolls are
provided during regular programming, an aural tone is required to
indicate to persons who are blind or who have low vision that emergency
information is being provided.
Useful Information on Other Emergency
The Federal Emergency Management Agency (FEMA)
is responsible for responding to national disasters and for helping
state and local governments and individuals prepare for emergencies.
The Department of Homeland Security
is responsible for preventing terrorist attacks within the United
States, reducing America's vulnerability to terrorism, and is also
responsible for minimizing the damage and handling recovery operations
if attacks do occur.
The Homeland Security Advisory System
provides a way to distribute information regarding the risk of terrorist
acts to federal, state, and local authorities and to the American
people. The system provides warnings in the form of a set of graduated
"Threat Conditions" that increase as the risk of the threat
increases. State Civil Defense alerts the public of any changes to the
threat level through the news media. In case of level red, the state
sounds the emergency alert siren. At each threat condition, federal
departments and agencies implement a corresponding set of
"Protective Measures" to further reduce vulnerability or
increase response capability during a period of heightened alert.
For additional information and/or advice on
communicating during emergencies or what to do during a national or
local emergency, visit FEMA's Website, www.fema.gov
or the Department of Homeland Security, www.dhs.gov/.
In the event of an emergency: