Replaces: 6.0
Date Issued: April 01,1995
Revised: April 24, 2001
Date Effective: April 24, 2001
The Authority Board recognizes that terminology is important to the complete understanding of the operation of an E9-1-1 system. The NENA Master Glossary of 9-1-1 Terminology (NENA-01-002 , March 1998), with limited local modification, has been approved by the Board as the local standard.
|
Term |
Definition |
|
1A2 |
A designation for Key Telephone Systems (KTS) which utilize an "A" lead for control. |
|
24-Hour Dispatch Center |
A facility, properly equipped and continuously staffed, to dispatch and communicate with emergency service personnel and equipment. A Public Safety Answering Point (PSAP) attendant, after interviewing the 9-1-1 caller, forwards pertinent information to the appropriate 24-Hour Dispatch Center for resource allocation and dispatch. [El Paso - Teller County 9-1-1 System Specific] (Also See Call Relay) |
|
9‑1‑1 |
A 3-digit telephone number to facilitate the reporting of an emergency requiring response by a public safety agency. |
|
9‑1‑1 Service Area |
The geographic area that has been granted authority by a state or local governmental body to provide 9‑1‑1 service. |
|
9‑1‑1 System |
The set of network, database and Customer Premise Equipment (CPE) components required to provide 9‑1‑1 service. |
|
9‑1‑1 Tandem |
(See Enhanced 9‑1‑1 Control Office) |
|
"A" Lead Control |
A wire used to control the Key Telephone Unit (KTU) in a 1A2 type Key Telephone System (KTS). In some Enhanced 9‑1‑1 (E9‑1‑1) systems it is used to identify the position connected to the trunk. |
|
Abandoned Call |
A call placed to 9‑1‑1 in which the caller disconnects before the Public Safety Answering Point (PSAP) attendant can answer the call. |
|
Access Line |
The connection between a customer premises network interface and the Local Exchange Carrier (LEC) that provides access to the Public Switched Telephone Network (PSTN). |
|
Advanced Mobile Phone Service
(AMPS) |
The analog radio interface utilized in cellular telephone systems. |
|
Alarm Dry Contacts |
A set of relay contacts which are caused to either open or close when an alarm condition occurs. (Ref. NENA 04‑001, Generic Standards for E9‑1‑1 PSAP Equipment) |
|
ALI Retrieval |
A request for an Automatic Location Identification (ALI) record from the Public Safety Answering Point (PSAP) to the ALI database. |
|
ALI Retrieval Rate |
The number of requests for Automatic Location Identification (ALI) that are not duplicated within a two (2) minute time frame. |
|
Alternate ISDN PSAP |
(See Alternate PSAP) |
|
Alternate Number |
Used in Interim Number Portability (INP), the caller's original telephone number, which is call forwarded to the new carrier's telephone number. Also known as Call Forward Number. |
|
Alternate PSAP |
A Public Safety Answering Point (PSAP) designated to receive calls when the primary PSAP is unable to do so. |
|
Alternate Routing |
The capability of routing 9‑1‑1 calls to a designated alternate location(s) if all 9‑1‑1 trunks to a primary Public Safety Answering Point (PSAP) are busy or out of service. May be activated upon request or automatically, if detectable, when 9‑1‑1 equipment fails or the PSAP itself is disabled. |
|
American Standard Code for
Information Interchange (ASCII) |
This standard defines the code for a character set to be used for information interchange between equipment of different manufacturers and is a standard for data communications over telephone lines. In the context of TDD/TTY (Telecommunications Device for the Deaf/Teletypewriter) this refers to both a binary code and modulation method used for 110/300 baud TDD/TTY communications. |
|
Amplitude Modulated (AM) |
The encoding of a carrier wave by variation of its amplitude in accordance with an Input signal. |
|
Angle of Arrival (AOA) |
A terrestrial Location Determination Technology (LDT) that computes a transmitter's location based upon the angle at which the transmitter's radio signal strikes multiple receivers. |
|
Answering Position |
(see Attendant Position) |
|
Attendant Position |
The Customer Premises Equipment (CPE) at which calls are answered and responded to by the Telecommunicator. |
|
Automatic Alarm and Automatic
Alerting Device |
Any automated device which will access the 9‑1‑1 system for emergency services upon activation and does not provide for two‑way communication. (Many states prohibit the dialing of 9‑1‑1 by an automated device.) |
|
Automatic Call Distributor
(ACD) |
Equipment that automatically distributes incoming calls to available Public Safety Answering Point (PSAP) attendants in the order the calls are received, or queues calls until an attendant becomes available. |
|
Automatic Location
Identification (ALI) |
The automatic display at the PSAP (Public Safety Answering Point) of the caller's telephone number, the address/location of the telephone and supplementary emergency services information. |
|
Automatic Location
Identification (ALI) Call Retrieval |
A process of counting ALI (Automatic Location Identification) database queries not duplicated within a two (2) minute time frame. |
|
Automatic Location
Identification (ALI) Customer Retrieval |
A process of counting ALI (Automatic Location Identification) database queries not duplicated within a twenty‑four (24) hour time frame. |
|
Automatic Location
Identification (ALI) Database |
The set of ALI (Automatic Location Identification) records residing on a computer system. |
|
Automatic Location
Identification (ALI) Multiplexer |
A CPE (Customer Premises Equipment) component which performs the function of communicating with the ALI (Automatic Location Identification) database. An ALI Multiplexer typically works in conjunction with an Automatic Number Identification (ANI) controller. |
|
Automatic Location
Identification (ALI) Retrieval |
The process of querying the 9‑1‑1 database for ALI (Automatic Location Identification) records. |
|
Automatic Number Identification
(ANI) |
Telephone number associated with the access line from which a call originates. |
|
Automatic Number Identification
(ANI) Controller |
A stand‑alone CPE (Customer Premises Equipment) component which provides the ANI (Automatic Number Identification) decoding and function key control for 9‑1‑1 service. |
Automatic Number Identification
Information Digits (ANI II Digits) |
Digits in the Enhanced MF (Multi‑Frequency) Signaling protocol that indicate to the PSAP (Public Safety Answering Point) CPE (Customer Premises Equipment) ANI (Automatic Number Identification) display device whether the display should remain steady or flash, or if the call is a test call. |
|
Average Busy Hour |
The 1‑hour period during the week statistically shown over time to be the hour in which the most telephone calls are received. |
|
Backup Public Safety Answering
Point (PSAP) |
Typically a disaster recovery answering point which serves as a backup to the primary PSAP (Public Safety Answering Point) and is not co‑located with the primary PSAP. |
|
Basic 9‑1‑1 |
An emergency telephone system, which automatically connects 9‑1‑1 callers to a designated answering point. Call routing is determined by the originating central office only. Basic 9‑1‑1 may or may not support Automatic Number Identification (ANI) and/or Automatic Location Identification (ALI). |
|
Baud Rate |
A measure of signaling speed in data communications that specifies the number of signaling elements that can be transmitted each second. |
|
Baudot Code |
A five bit encoding scheme that represents text and digits. It is the standard transmission signaling scheme used by TTY/TDD devices. (Teletypewriter/Telecommunication Device for the Deaf) (per EIA PN‑1663) |
|
Binary Coded Decimal (BCD) |
A coding system in which each decimal digit from 0 to 9 is represented by four binary (0 or 1) digits. (Ref. NENA 04‑002, PSAP Master Clock Standard) |
|
Busy Hour |
The hour each day with the greatest call volume. |
|
Busy Tone |
An audible signal indicating a call cannot be completed because the called access line is busy. The tone is applied 60 times per minute. |
|
Call Check |
(see Recall Recorder) |
|
Call Detail Logging |
The process of recording incoming call data. Also known as an ANI (Automatic Number Identification) printout. (Ref. NENA 04‑001, Generic Standards for E9‑1‑1 PSAP Equipment ) |
|
Call Progress Signals |
Audible cues to advise 9‑1‑1 callers of the status of their call. (e.g. Busy Tone, Reorder Tone) |
|
Call Relay |
Forwarding of pertinent information by a Public Safety Answering Point (PSAP) attendant to the appropriate response agency (Not to be confused with Telephone Relay Service). |
|
Call Sequencer |
A unit which monitors incoming calls at a PSAP (Public Safety Answering Point) and indicates to the answering positions, which of the incoming calls has been unanswered the longest. |
|
Call Transfer |
The capability to redirect a call to another party. |
|
Calling Party Hold |
The capability of the PSAP (Public Safety Answering Point) to maintain control of a 9‑1‑1 caller's access line, even if the caller hangs up. |
|
Calling Party's Number (CPN) |
The call back number associated with a wireless telephone. (Similar to ANI (Automatic Number Identification) for wireline telephones.) (Ref. NENA 03‑002, Recommendation for the Implementation of Enhanced MF Signaling, E9‑1‑1 Tandem to PSAP) |
|
Code Division Multiple Access
(CDMA) |
A digital radio interface utilized by some North American PCS (Personal Communications Service) carriers. |
|
Carrier Frequency |
The frequency of the unmodulated IRIG (Inter‑Range Instrumentation Group) B or E signal. (Ref. NENA 04‑002, PSAP Master Clock Standard) |
|
Cathode Ray Tube (CRT) |
Video monitor used for displaying information. |
|
Cell |
The wireless telecommunications antenna (Cellular or PCS) serving a specific geographic area. |
|
Cell Face |
(See Cell Sector) |
|
Cell Sector |
One face of a cell antenna (typically 3‑sided) that operates independently of the other sectors. |
|
Cell Site |
The location of a wireless telecommunications antenna (Cellular or PCS) and related equipment. |
|
Cellular Priority Access
Service (CPAS) |
A uniform nationwide method of providing priority access to authorized wireless subscribers in the event of an emergency. |
|
Central Office (CO) |
The Local Exchange Carrier (LEC) facility where access lines are connected to switching equipment for connection to the Public Switched Telephone Network (PSTN). |
|
Central Processing Unit (CPU) |
The part of a computer which performs the logical, computational and decision making functions. |
|
Centralized Automated Message
Accounting (CAMA) |
A Multi‑Frequency (MF) signaling protocol originally designed for billing purposes, capable of transmitting a single telephone number. |
|
Centrex |
A business telephone service offered by some Local Exchange Carriers (LEC) that provides PBX (Private Branch Exchange) type features over access lines. |
|
Circuit Route |
The physical path between two terminal locations. |
|
Class of Service |
A designation of the type of telephone service, e.g. residential, business, centrex, coin, PBX, wireless. |
|
Company Identifier (Company ID) |
A 3‑5 character identifier chosen by the Local Exchange Carrier (LEC) that distinguishes the entity providing dial tone to the end user. The Company Identifier is maintained by NENA (National Emergency Number Association) in a nationally accessible database. |
|
Computer Aided Dispatch (CAD) |
A computer based system that aids Public Safety Answering Point (PSAP) attendants by automating selected dispatching and record keeping activities. |
|
Conference Transfer |
The capability to bridge a third party onto an existing call. Also known as three‑way calling. |
|
Consolidated PSAP |
A facility where one or more Public Safety Agencies choose to operate as a single 9‑1‑1 entity. |
|
Control Office |
(see Enhanced 9‑1‑1 (E9‑1‑1) Control Office) |
|
Customer Comments |
Supplementary information useful in dispatching, provided in conjunction with Automatic Location Identification (ALI) displays. |
|
Customer Premises Equipment (CPE) |
Terminal equipment at a PSAP (Public Safety Answering Point). |
|
Cutover |
The activation of a new telephone call processing or switching system. |
|
Data Base |
An organized collection of information, typically stored in computer systems, comprised of fields, records (data) and indexes. In 9‑1‑1, such data bases include MSAG (Master Street Address Guide), telephone number/ESN (Emergency Service Number), and telephone customer records. |
|
Data Base Management System (DBMS) |
A system of manual procedures and computer programs used to create, store and update the data required to provide Selective Routing and/or Automatic Location Identification (ALI) for 9‑1‑1 systems. |
|
Data Base Management System Provider |
Entity providing Selective Routing (SR) and/or Automatic Location Identification (ALI) data services. |
|
Data Bit |
A binary digit, either a zero (0) or a one (1). |
|
Data Exchange |
The process of exchanging 9‑1‑1 data between Service Providers and the Data Base Management System Provider. |
|
Data Processing Day |
The day in which processing of a given service order update occurs. |
|
Decaying |
Directions from positive to negative, relative to the starting points, whose transient amplitudes decay with time in a ringwave pattern. These transients are typically caused by sources internal to the PSAP (Public Safety Answering Point), such as motors, lighting, inductive loads, etc. (Ref. NENA 04‑001, Generic Standards for E9‑1‑1 PSAP Equipment ) |
|
Dedicated Trunk |
A telephone circuit used for a single purpose, such as transmission of 9‑1‑1 calls. |
|
Default Routing |
The capability to route a 9‑1‑1 call to a designated (default) PSAP (Public Safety Answering Point) when the incoming 9‑1‑1 call cannot be selectively routed due to an Automatic Number Identification (ANI) failure or other cause. |
|
Dial Tone First |
The provision of dial tone to enable a caller to originate and complete 9‑1‑1 calls from public telephones without inserting a coin or any other device. Also known as coin‑free dialing. |
|
Direct Dispatch |
The performance of 9‑1‑1 call answering and dispatching by personnel at the primary PSAP (Public Safety Answering Point). |
|
Directory Number (DN) |
A dialable 10-digit telephone number associated with a telephone subscriber or call destination. |
|
Discrepancies |
A Service Provider term used to describe subscriber records that do not match the MSAG (Master Street Address Guide) and are referred to an error file or report for resolution. |
|
Disk Operating System (DOS) |
A personal computer operating system which manages the computer's resources. |
|
Diverse Routing |
The practice of routing circuits along different physical paths in order to prevent total loss of 9‑1‑1 service in the event of a facility failure. |
|
Dual Tone Multi‑Frequency (DTMF) |
One of the methods used for signaling in the telephone network. Often referred to as TOUCH‑TONETM. |
|
Electronic Key Telephone System (E‑Key) |
A multi‑line telephone system, which utilizes stored program control technology instead of KSU's (Key Service Units) and KTU's (Key Telephone Units). |
|
Emergency Call |
A telephone request for public safety agency emergency services which requires immediate action to save a life, to report a fire or to stop a crime. May include other situations as determined locally. |
|
Emergency Message (EM) Circuits |
The special service circuits used to carry 9‑1‑1 calls to the PSAP (Public Safety Answering Point). |
|
Emergency Ring Back |
The capability of a Public Safety Answering Point (PSAP) attendant to ring the telephone on a held circuit. Requires Calling Party Hold. Also known as re‑ring. (A Basic 9‑1‑1 feature) |
|
Emergency Service Central
Office Number (ESCO) |
The information delivered to the PSAP (Public Safety Answering Point) when there is an Automatic Number Identification (ANI) failure between the end office and the 9‑1‑1 Control Office. When Automatic Number Identification (ANI) is not available, the 9‑1‑1 call is default routed and the ANI display at the PSAP (Public Safety Answering Point) will be "911‑0TTT" (or 911‑TTTT) with TTT identifying the incoming trunk group. |
|
Emergency Service Number (ESN)
/ Emergency Service Zone (ESZ) |
An ESN is a 3 to 5-digit number representing a unique combination of emergency service agencies (Law Enforcement, Fire, and Emergency Medical Service) designated to serve a specific range of addresses within a particular geographical area, or Emergency Service Zone (ESZ). The ESN facilitates selective routing and selective transfer, if required, to the appropriate PSAP (Public Safety Answering Point) and the dispatching of the proper service agency(ies). |
|
Emergency Service (ES) Trunks |
Message trunks capable of providing Automatic Number Identification (ANI), connecting the serving central office of the 9‑1‑1 calling party and the designated E9‑1‑1 Control Office. |
|
End Office |
(See central office). |
|
End User |
The 9‑1‑1 caller |
|
Enhanced 9‑1‑1 (E9‑1‑1) |
An emergency telephone system which includes network switching, database and CPE (Customer Premises Equipment) elements capable of providing Selective Routing, Selective Transfer, Fixed Transfer, ANI (Automatic Number Identification) and ALI (Automatic Location Identification). |
|
Enhanced 9‑1‑1 (E9‑1‑1)
Control Office |
The Central Office that provides the tandem switching of 9‑1‑1 calls. It controls delivery of the voice call with Automatic Number Identification (ANI) to the PSAP (Public Safety Answering Point) and provides Selective Routing, Speed Calling, Selective Transfer, Fixed Transfer, and certain maintenance functions for each PSAP. Also known as 9‑1‑1 Selective Routing Tandem or Selective Router. |
|
Enhanced 9‑1‑1 (E9‑1‑1)
Tandem Office |
(See E9‑1‑1 Control Office) |
|
Essex |
(See Centrex) |
|
Exchange |
A defined area, served by one or more telephone central offices, within which a Local Exchange Carrier (LEC) furnishes service. |
|
Exempt Lines |
Access lines not subject to 9‑1‑1 charges. |
|
Fast Busy |
(see Reorder Tone) |
|
Feature Group D (FGD) |
A Multi‑Frequency (MF) signaling protocol, originally developed to support equal access to long distance services, capable of carrying one or two 10-digit telephone numbers. |
|
Fixed Transfer |
The capability of a Public Safety Answering Point (PSAP) attendant to transfer a 9‑1‑1 call to a pre‑determined location by activating a single button. (Also called a One‑Button Transfer.) |
|
Footprint |
The geographic area covered by a particular wireless cell or cell sector. |
|
Forced Disconnect |
The capability of a PSAP attendant to disconnect a 9‑1‑1 call, even if the calling party remains off‑hook. Used to prevent overloading of 9‑1‑1 trunks. |
|
Foreign Exchange Service (FX) |
A telephone line switched in an exchange or central office other than the exchange or central office area in which the telephone is located. |
|
Free Run |
The operating condition of a clock in which the local oscillator is not locked to an external synchronization reference, and is using no storage techniques to sustain its operating frequency. (Ref. NENA 04‑002, PSAP Master Clock Standard) |
|
Global Positioning System (GPS) |
A satellite based Location Determination Technology (LDT). |
|
Grade of Service |
The probability (P), expressed as a decimal fraction, of a telephone call being blocked. P.01 is the grade of service reflecting the probability that one call out of one hundred during the average busy hour will be blocked. P.01 is the minimum recommended Grade of Service for 9‑1‑1 trunk groups. |
|
Global Standard for Mobile
Communications (GSM) |
International standard digital radio interface utilized by some North American PCS (Personal Communications Service) carriers. |
|
Hearing Carry Over (HCO) |
A method which utilizes both voice and text communications on the same call, allowing a person who is speech impaired to listen to the other party's conversation and respond by typing via a TTY (Teletypewriter - also known as TDD) or other means for text communications. |
|
Highway Call Box |
A telephone enclosed in a box and placed along a highway that allows a motorist to summon emergency and non‑emergency assistance. |
|
Idle Circuit Tone Application |
A feature which applies a distinctive tone toward the Public Safety Answering Point (PSAP) attendant to distinguish between calls that have been abandoned before the attendant answers, and calls where the caller is unable or unwilling to speak. |
|
Impulse Transient |
A high energy unidirectional voltage or current impulse resembling a "spike" which is typically caused by sources external to the PSAP (Public Safety Answering Point), such as lightning, grid switching, etc. (Ref. NENA 04‑001, Generic Standards for E9‑1‑1 PSAP Equipment) |
|
Instant Playback Recorder |
(see Recall Recorder) |
|
Integrated Services Digital
Network (ISDN) |
A digital interface providing multiple channels for simultaneous functions between the network and CPE (Customer Premises Equipment). |
|
Inter‑local Services
Agreement |
An agreement among governmental jurisdictions or privately owned systems, or both, within a specified area to share 9‑1‑1 system costs, maintenance |