ACCOLC (Access Overload Control) was a procedure in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...

for restricting

mobile telephone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ...

usage in the event of emergencies. It is similar to the GTPS (

Government Telephone Preference Scheme The Government Telephone Preference Scheme (GTPS) was a British system for limiting outgoing calls from landlines if the network was overloaded during an emergency. Numbers registered under the GTPS were still be able to make outgoing calls if th ...

) for

landline A landline (land line, land-line, main line, home phone, fixed-line, and wireline) is a telephone connection that uses metal wires or optical fiber telephone line for transmission, as distinguished from a mobile cellular network, which uses ...

s. This scheme allowed the mobile telephone networks to restrict access in a specific area to registered numbers only and is normally invoked by the Police Incident Commander (although it can be invoked by the

Cabinet Office The Cabinet Office is a department of His Majesty's Government responsible for supporting the prime minister and Cabinet. It is composed of various units that support Cabinet committees and which co-ordinate the delivery of government objecti ...

). The

emergency service Emergency services and rescue services are organizations that ensure public safety and health by addressing and resolving different emergencies. Some of these agencies exist solely for addressing certain types of emergencies, while others deal wit ...

s are responsible for registering their key numbers in advance. ACCOLC was replaced by

MTPAS MTPAS (Mobile Telecommunication Privileged Access Scheme) is a British procedure for prioritising access to the mobile telephone networks for privileged persons (members of emergency services as designated at a local level). It replaced ACCOLC in ...

(Mobile Telecommunication Privileged Access Scheme) in 2009.

Purpose

The purpose of ACCOLC (US) was to restrict non-essential access to cellular phone networks during emergencies. This actively prevents unnecessary usage from congesting the cell networks, thus allowing emergency services personnel priority for communications. It also serves to control information flow in and out of a declared emergency area. Mobile networks can become overwhelmed by a high concentration of calls that often occur immediately after a major incident. Reliable access to the mobile networks, even during times when an exceptionally large number of calls are being made, is achieved by installing a special SIM (subscriber identity module) card in the telephone handset. Special SIMs are only available to entitled users within the emergency services community, and not to members of the public. Verizon Wireless in the United States has also implemented ACCOLC on its wireless networks, the modalities of use may differ from those in Britain especially with regards to ACCOLC being activated permanently on the network.

Implementation

In an emergency situation, the mobile network operator can implement ACCOLC onto specific mobile cell sites (that cover the area of the required restriction). Most systems allow the operator to allow/restrict specific Access Class levels to gain access to the cell sites. The customer's

SIM card file:SIM-Karte von Telefónica O2 Europe - Standard und Micro.jpg, A typical SIM card (mini-SIM with micro-SIM cutout) file:Sim card.png, A smart card taken from a Global System for Mobile Communications, GSM mobile phone file:Simkarte NFC SecureE ...

is provisioned with an Access Class level between 0 and 15. Most SIM cards will be coded with a random access class level between 0 and 9. For special case mobile customers – e.g. emergency services, government officials, civil defence, etc. they will be issued with a SIM card with a high access class value (between 10 and 15). When the mobile operator needs to implement ACCOLC restriction, they will update the configuration on the specified cell sites. The access class value is a field that is transmitted in the broadcast channel of the cell. Under normal conditions, access class levels 0 – 15 are allowed. The SIM card compares what is allowed to its own access class level. If the allowed access class levels being broadcast by the cell site does not match what is on the SIM card, then the mobile device cannot access that cell – for any services.

Use

ACCOLC was deployed at the

Hillsborough disaster The Hillsborough disaster was a fatal human crush during a football match at Hillsborough Stadium in Sheffield, South Yorkshire, England, on 15 April 1989. It occurred during an FA Cup semi-final between Liverpool and Nottingham Forest in the ...

References

External links

London Assembly 7 July Review Committee Volume 4 Follow up report
Including report on ACCOLC being invoked around

Aldgate Aldgate () was a gate in the former defensive wall around the City of London. It gives its name to Aldgate High Street, the first stretch of the A11 road, which included the site of the former gate. The area of Aldgate, the most common use of ...

on 7 July by the

City of London Police The City of London Police is the territorial police force responsible for law enforcement within the City of London, including the Middle and Inner Temples. The force responsible for law enforcement within the remainder of the London region, ou ...

without reference to

GOLD Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile met ...

control.
Introduction to Resilient Communications (Cabinet Office).
{{DEFAULTSORT:Accolc Emergency management in the United Kingdom History of telecommunications in the United Kingdom Mobile telecommunications standards

Purpose

Implementation

Use

See also

References

External links