Glossary of 9-1-1 Terms
ACD - Automatic Call Distributor - routes incoming 911 calls to the first available operator
ADA - Federal Act providing for accessibility of disabled persons. The Act requires equal access for the disabled in obtaining emergency services.
ALI - Address Location Identification. The ability to display the address of the phone from which 9-1-1 was dialed. Accomplished through preloading the telephone company's computer memory links with the proper information. Must have Automatic Number identification service installed before ALI can be installed.
ANI - Automatic Number Identification. The ability to display the phone number of the telephone from which 9-1-1 was dialed in the same manner as ALI. Does not require ALI service installed.
APCO - Associated Public Safety Communication Officials professional association which is used for up to date information on telecommunications and training.
ASCII American Standard Code for Information Interchange. This is a character set used for information interchange and is the standard for data communications over telephone lines.
AVL - Automatic Vehicle Location. A system that shows the position of response vehicles on a map display.
B 9-1-1 - Basic 9-1-1. An Emergency Telephone Number System using the digits "9-1-1" for access and routing all such calls to a staffed 9-1-1 Answering Point.
BAUDOT A five bit coding scheme that represents text and digits. It is used for data communications by some TDD instruments.
BUSY HOUR CALLS - The number of calls anticipated during each Public Safety Answering Point's busiest period.
CAD - Computer-Aided Dispatching, also referred to as Computer-Assisted Dispatching. Public Safety dispatching with computers aiding in the process. This aid may be a simple display of pertinent information on a screen, up to the actual selection and notification of field unit(s) by the computer. 9-1-1 Systems may be interfaced with CAD systems.
CALL CONFERENCING - A call that is relayed from a PSAP to another PSAP or to another emergency service (related) agency, and in which the telecommunicator stays on the line to obtain additional information.
CALL HANG-UP Citizen dialing 9-1-1 hangs-up before an operator can answer the call. This will require a callback unless the call was placed at a pay phone.
CALL TRANSFERRING - A call that is relayed from a PSAP to an another PSAP or to another emergency service (related) agency, and in which the telecommunicator has no need for additional information and therefore disconnects once the transfer has been completed.
CALL VOLUME - This is the anticipated daily total number of call: For each Public Safety Answering Point.
CALLBACK This occurs when an operator, using ANI, ALI information, must call a citizen back after the citizen hangs up.
CAMA Central Automated Messaging Accounting. The dedicated line or trunk used in routing 9-1-1 calls. They run from the CO to the PSAP.
CANCEL - Button on the Automatic Number Identification unit, used to cancel an attempt to transfer when a busy signal or no answer is encountered.
CLASS - Type of telephone from which a call is placed (i.e., business, residential, coin, PBX, etc.)
CMRS - Commercial Mobile Radio Services (see LANDLINE and WIRELESS)
CO - Central Office. Telephone Company sites where calls are received and switched to the number that is dialed. A central office may handle one or more telephone exchanges. The central office may be an Electronic Switching System (ESS: necessary for Enhanced 9-1-1) or the older Electro-mechanical type.
CONFERENCING - Allowing three parties (citizen, police, fire/EMS to talk to each other simultaneously on the same line.
CUTOVER - Date of (9-1-1) System activation.
DATA BASE - The pre-recorded information or data that describes a collection of items. For 9-1-1 these items are telephone numbers, address information, and routing information. This is the heart of an Enhanced 9-1-1 System.
DEDICATED TRUNKS - Telephone lines that run directly from the BeIISouth Central Office exclusively carrying calls intended for a given destination.
DEFAULT- A condition that exists when the computer cannot find certain required information in the database. Rather than ignoring the call the computer will use Default procedures to ensure that the call is answered by a Law Enforcement Public Safety Answering Point within the System.
E 9-1-1 - Enhanced 9-1-1. An Emergency Telephone Number System using the digits 9-1-1 for access and computerized procedures for automatic routing to the proper Law Enforcement Agency (Publication Safety Answering Point). E-9-1-1 includes ANI and ALI information.
E-9-1-1 TANDEM The telephone company switch located in the CO that selectively routes 9-1-1 calls to the appropriate PSAP.
EMERGENCY CALL - A call routed to a PSAP reporting an incident, either in progress or just occurred, which presents a potential threat to life or property and which requires an immediate response from one or more public safety entities (law enforcement, fire, fire/rescue, EMS).
EMS - Emergency Medical Services.
EMS CALLS - The number of calls anticipated requiring the assistance of Emergency Medical Services (ambulance services).
ENP - Emergency Number Professional - a national certification through NENA.
ESN- Emergency Service Number. A three-digit number which identifies jurisdictional boundaries. The 9-1-1 computer associates the ESN with the address and routes the call to the appropriate PSAP.
EXCHANGE - The three number prefix (first three numbers of a telephone number following the area code) which identifies the central office muting of the call. It appears on the Automatic Number Identification display as the second set of numbers, following the area code.
FCC - Federal Communications Commission
FEMA - Federal Emergency Management Agency
FIRE SERVICE CALLS - The number of calls anticipated to require assistance of a Fire Service Agency.
FORCED DISCONNECT - The call is automatically disconnected within the Public Safety Answering Point Telecommunicator hangs up.
FX - Foreign Exchange line. A telephone number; located in an area not within the geographical boundaries of the local 9-1-1 service area, but draws dial tone service from a CO within the 9-1-1 service area.
GGM - Graphic Geofile Manager. A Geographic Information System (GIS) specifically designed to update the addresses and zones for the Computer Aided Dispatch (CAD) system and maps for the Tactical Map Display (TMD).
GIS - Geographic Information System. A computer system which is used to generate and edit maps.
IMPLEMENTATION - Preparation for activation of a 9-1-1 System.
L/E (OR LE) - Law Enforcement.
L/E CALLS - Law Enforcement calls. The number of calls anticipated requiring the assistance of a Law Enforcement Agency.
LANDLINE and WIRELESS - Generalized terms used to distinguish Telecommunication Companies which provide hard wired telephones and those that provide Commercial Mobile Radio Services (CMRS), Personal Communication Service (PCS), or Cellular Radio .
MDT - Mobile Data Terminal. A computer which allows a field unit to send and receive messages from the communications center. A MDT can also be used to generate electronic reports.
MSAG - Master Street Address Guide. The MSAG contains all of the streets and house number ranges in the E 9-1-1 service area. The streets and address ranges are assigned ESNs to enable proper routing of 9-1-1 calls.
N-1-1 Code or N-1-1 number - Any telephone number whose first number is any digit other than "0" or "1" and the last two digits are both "1", which, when dialed, is sufficient to access the called entity.
NENA - National Emergency Number Association. Professional organization with particular emphasis on 911
NUMBER PORTABILITY - Right to maintain the same telephone number when a customer changes to a different local service provider.
ONE BUTTON TRANSFER - The ability to conference another Public Safety Agency by pressing one button. Designed for Enhanced 9-1-1 Systems, it requires Automatic Number Identification service.
OEP - Office of Emergency Preparedness
PARTY LINE Multiple users on a single telephone line. Each customer is at a different location, which defeats E-9-1-1.
PBX Private Branch Exchange. A telephone switch installed on a customer site. It defeats E-911 by not providing accurate ANI and ALI.
PCS - Personal Communication Service (see LANDLINE and WIRELESS)
PRANK CALL Inappropriate use of the 9-1-1 system, when a caller dials 9-1-1 with a non-emergency call; often children do this as a joke.
PSAP - Public Safety Answering Point. The agency responsible for the jurisdiction from which the 9-1-1 call originated and to which the call is routed.
PSC - Public Service Commission (Also LA-PSC)
PSDP - Pubic Safety Dispatch Point. The agency location that is responsible for the actual dispatch of the call.
REPEAT ALI - A button on the Automatic Number Identification unit, used only while the caller is still on the line to redisplay the address Location Information for clarity. Used if you get a garbled display, "No Record Found," etc.
SPEED CALL NUMBER - A two-digit number prefixed by a star (*, used to transfer a 9-1-1 call to a PSAP not on a present routing button.
SR - Selective Routing. Procedure whereby a call received at a TelCo's End Office (the first junction point after a call leaves the caller's home) must be routed based on its point of origin rather that on the number dialed; e.g. a 9-1-1 call goes to the end office and this office covers telephone exchanges that overlap a Parish boundary. The Selective Router automatically sends the call to the proper emergency center (PSAP).
SWITCH HOOK - The cradle that the telephone handset lies in.
TDD (TTY) - Telecommunication Device for the Disabled - used to facilitate communications between deaf citizens and 911 operators, consists of typing text messages to and from the caller.
TELCO - Telephone Company
TELECOMMUNICATIONS ACT - Federal Act originally enacted in 1934. It was totally rewritten in 1996 governing all aspects of telecommunications from telephones to cable television to the Internet. Its provisions include regulation of telephone numbering, number portability, wireless frequency regulation and wireless and wireline licensing, etc.
TMD - Tactical Map Display. A computer screen which displays geographical information (streets and common places) to aid dispatchers.
TRANSFER LOCATION - If the service needed is not supplied at the PSAP, then the call will be transferred (conferenced) to the proper agency.
TRS - Telephone Relay Services. Locations which receive calls from persons with hearing and/or speech disabilities usually through a TDD/TTY The operator receiving the call will then place a voice call on behalf of the TDD/TTY caller, acting as a communication intermediary between the two parties.
TRUNK LINE - Bell System circuit from the central office to the phone end user's location.
UDT - Universal Data Transfer. A computer that records and stores data generated by the Computer Aided Dispatch (CAD) system.
UPS - Uninterruptible Power Supply. An auxiliary power unit for a phone system which provides continuous battery backup power in the event of a commercial power failure.