ASTM F1381-92

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: F 1381 – 92
Standard Guide for
Planning and Developing 9-1-1 Enhanced Telephone
Systems
This standard is issued under the fixed designation F 1381; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Terminology
1.1 This guide recommends minimum performance require-
2.1 Definitions:
ments for enhanced access to public safety services using the
2.1.1 9-1-1, n—a three-digit telephone number to facilitate
North American standard emergency telephone number, 9-1-1.
the reporting of an incident or situation requiring response by
1.2 This guide provides assistance to states, counties, and
a public safety agency.
local jurisdictions in the development of 9-1-1 enhanced
2.1.2 Poisson Distribution, n—a probability density func-
systems.
tion that is often used as a mathematical model of the number
1.3 This guide makes recommendations for planning and
of outcomes obtained in a suitable interval of time and space.
organizational needs in the development of 9-1-1 enhanced
In 9-1-1 it is used to predict potential call blockage during
systems.
normal busy periods.
1.4 This guide does not address access to public safety
2.2 Definitions of Terms Specific to This Standard:
response services through means other than use of the 9-1-1
2.2.1 abandoned call, n—a call placed to 9-1-1 in which the
telephone number.
caller disconnects before the call can be answered by the public
1.5 This guide applies only to the use of the number 9-1-1
safety answering point (PSAP) attendant.
to request a public safety response, from the point of initiation
2.2.2 action agency, n—the public safety agency having a
of the call through the point that the caller is connected to the
legal or consensual obligation to respond to a call for service.
responsible agency, or essential information needed for dispo-
2.2.3 alternate routing, n—the capability of automatically
sition of the call, or both, is received.
1.6 The sections in this guide are arranged in the following rerouting 9-1-1 calls to a designated alternate location(s) if all
9-1-1 trunks from a central office or to a primary PSAP are
order:
busy or out of service. May also be activated upon request, or
Section
Scope 1
automatically if detectable, when 9-1-1 equipment fails or the
Terminology 2
PSAP itself is disabled.
Significance and Use 3
Concept of Operation for 9-1-1 Telephone Systems 4
2.2.4 answering position, n—an appropriately equipped lo-
9-1-1 Performance Factors 4.1
cation within a PSAP that is used to receive incoming 9-1-1
9-1-1 Performance Requirements 4.2
calls.
Coordinating 9-1-1 Systems 5
State 9-1-1 Statutory Provisions 6
2.2.5 audible signal, n—a sound that indicates an incoming
9-1-1 Funding 7
9-1-1 call.
Funding Alternatives 7.1
Funding considerations 7.2
2.2.6 automatic call distributor (ACD), n— equipment that
Geographical Data Bases 8
distributes incoming calls to available PSAP attendants in the
Automatic Location Identification 8.1
order the calls are received, or holds calls until an attendant
Uniform Address Program 8.2
Selective Call Routing 8.3
becomes available.
Service Areas 8.4
2.2.7 automatic location identification (ALI), n—the auto-
Other Planning Concerns 9
Public Education 9.1
matic display at the PSAP of the caller’s telephone number, the
Personnel Training 9.2
address for the telephone and supplementary information.
2.2.8 automatic number identification (ANI), n—the auto-
1.7 This standard does not purport to address all of the
matic display at the PSAP of the caller’s telephone number.
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 2.2.9 average busiest hour, n—the 1-h period during the
priate safety and health practices and determine the applica- week statistically shown over time to be the hour in which the
bility of regulatory limitations prior to use. most emergency telephone calls are received.
This guide is under the jurisdiction of ASTM Committee F-30 on Emergency Current edition approved Feb. 15, 1992. Published April 1992.
Medical Services and is the direct responsibility of Subcommittee F30.04 on
Communications.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
F 1381
2.2.10 call detail logging, n—a means of establishing chro- 2.2.28 data management system (DMS), n—the combina-
nological and operational accountability for each 9-1-1 call tion of manual procedures and computer programs used to
processed, consisting minimally of the caller’s telephone create, store, manipulate, and update data required to provide
number, the date and time the 9-1-1 telephone equipment selective routing and ALI.
established initial connection (trunk seizure), the time the call 2.2.29 dedicated trunk, n—a telephone circuit used for one
was answered, the time the call was transferred (if applicable),
purpose only; that is, transmission of 9-1-1 calls.
the time the call was disconnected, the trunk line used, and the
2.2.30 default routing, n—the capability to route a 9-1-1 call
identity of the PSAP attendant’s position. Also known as ANI
to a designated (default) PSAP when the incoming 9-1-1 call
printout.
cannot be selectively routed due to an ANI failure, garbled
2.2.11 called party hold, n—the capability to maintain digits, or other cause.
control of an incoming 9-1-1 call by a PSAP attendant for
2.2.31 dial tone first, n—the provision of dial tone to enable
tracing or confirmation of an emergency even if the caller
a caller to originate and complete 9-1-1 calls from public
hangs up.
telephones without inserting a coin or any other device. Also
2.2.12 call progress signals, n—audible cues to advise
known as coin-free dialing.
9-1-1 users of the status of their calls.
2.2.32 direct dispatch, n—the functions of 9-1-1 call an-
2.2.13 call relay, n—disposition of a 9-1-1 call by the swering and dispatching are both performed by personnel at the
notation of pertinent information by the PSAP attendant who
primary PSAP.
forwards the information to the action agency.
2.2.33 diverse routing, n—the practice of routing calls
2.2.14 call referral, n—disposition of a 9-1-1 call by advice
through different circuit paths in order to prevent total loss of
to the caller of the appropriate numbers to call other than 9-1-1.
the 9-1-1 system in the event an individual circuit is disabled.
2.2.15 call transfer, n—the extending of a 9-1-1 call by a
2.2.34 emergency service number (ESN), n— a number used
PSAP attendant to connect the caller with the action agency. in the DMS to designate the public safety agencies responsible
2.2.16 central offıce (CO), n—a telephone company facility for service to the location of each telephone in a 9-1-1 service
that houses the switching and trunking equipment serving area, for the purpose of determining call routing. Also see
telephones in a defined area. Also known as end offıce. emergency service zone (ESZ).
2.2.17 circuit routes, n—a means of two-way communica- 2.2.35 electronic switching system (ESS), n— a central
tion between two terminal installations. office with programmable switching logic. Can also be used as
2.2.18 class of service, n—a service order code designation a tandem.
of the telephone service features to which business and 2.2.36 emergency service zone (ESZ), n—a defined geo-
residence customers subscribe. graphical territory consisting of a specific combination of law
2.2.19 computer-aided dispatch (CAD), n— a computer- enforcement, fire, and emergency medical coverage areas. Also
see emergency service number (ESN).
based system intended to increase the efficiency and accuracy
of public safety call handling and dispatching. 2.2.37 end office, n—see central offıce.
2.2.20 computer-aided dispatch (CAD) interface, n—the 2.2.38 enhanced 9-1-1, n—a telephone system which in-
means of automatically introducing the ALI data into a cludes ANI, ALI, and (optionally) selective routing, to facili-
computer-aided dispatch (CAD) system, as opposed to manu- tate appropriate public safety response.
ally entering the information. 2.2.39 exchange, n—a defined area, served by one or more
2.2.21 conference transfer, n—the capability of transferring telephone central offices, within which a telephone company
a call to the action agency and allowing the PSAP attendant to furnishes service.
monitor or participate in the call after it has been transferred to 2.2.40 fixed transfer, n—the capability of a PSAP attendant
the action agency. Also known as three-way calling.
to transfer a 9-1-1 call to the agency associated with a single
2.2.22 contiguous agency, n—a public safety agency whose button.
jurisdiction is adjacent to the area served by a 9-1-1 system. 2.2.41 forced disconnect, n—the capability of a PSAP
2.2.23 cross tandem transfer, n—the capability of transfer- attendant to disconnect a 9-1-1 call to prevent jamming of the
ring a call over the 9-1-1 network from a PSAP served by one incoming lines.
tandem office to another PSAP served by a different tandem 2.2.42 foreign exchange (FX) service, n— a telephone line
office.
switched in an exchange or central office other than the
2.2.24 customer comments, n—supplementary information exchange or central office in which the telephone is located.
useful in dispatching, provided in conjunction with ALI dis- 2.2.43 interconnect, n—the connection of the serving tele-
plays.
phone company’s equipment with the equipment of another
2.2.25 customer premises equipment (CPE), n— terminal vendor. Also a generic term used to refer to a non-telephone
equipment at a PSAP or secondary answering location. company vendor.
2.2.26 cutover, n—the actuation of a new telephone call 2.2.44 interlocal services agreement, n— an agreement
processing or switching system. among governmental jurisdictions or privately owned systems,
2.2.27 data base, n—a collection of information organized or both, within a specified area to share 9-1-1 system costs,
maintenance responsibilities, and other considerations.
in a computer to facilitate rapid search and retrieval. In this
guide, such data bases include MSAG, telephone number/ESN, 2.2.45 logging recorder, n—a device that records date/time,
and telephone customer records. voice communications, and other transactions involved in the
F 1381
processing of calls to a PSAP. 2.2.64 tandem offıce, n—the location of the routing table
and equipment to direct 9-1-1 calls to the appropriate PSAP.
2.2.46 main station, n—a telephone that is connected di-
rectly to a central office and has a unique telephone number. It 2.2.65 TDD/TTY, n—a telecommunication device for the
hearing or speech impaired, or both.
is not an extension.
2.2.66 thousands number group, n—the entire last four-digit
2.2.47 master street address guide (MSAG), n— a data base
group of numbers in an exchange, sometimes used to deter-
of street names and address ranges within their associated
mine default routing locations.
communities defining emergency service zones for 9-1-1
2.2.67 trunk, n—a circuit connecting switching equipment
purposes.
at two sites (for example, between a PBX and central office,
2.2.48 network, n—an arrangement of main stations inter-
between two central offices).
connected by means of communications channels organized to
2.2.68 trunk group, n—one or more trunks terminated at the
perform or serve a common function.
same two points.
2.2.49 nonselective routing, n—the capability of routing
2.2.69 trunk seizure, n—the point at which a call is assigned
9-1-1 calls by the use of the NXX or trunk group.
to a trunk and acknowledgement is provided by the 9-1-1 call
2.2.50 NXX, n—the first three digits of a local telephone
processing equipment.
number that identifies the central office switching location
2.2.70 uninterruptible power system (UPS), n— the capa-
within its area code. Also erroneously referred to as NNX.
bility of providing a continuous source of power without regard
2.2.51 P.01 grade of service, n—a measure of emergency
to the interruption or loss of commercial power. Also known as
telephone service in which no more than one call in 100
uninterruptible power supply.
attempts will be blocked during the average busiest hour.
2.3 Abbreviations:
2.2.52 pilot number, n—a telephone customer’s main ac-
2.3.1 NHTSA—National Highway Traffic Safety Adminis-
count number, lead number, listed number, or billing number.
tration, United States Department of Transportation.
2.2.53 private branch exchange (PBX), n— a private, inter-
2.3.2 NTIA—National Telecommunications and Informa-
nally switched telephone system, of significance to 9-1-1
tion Administration, United States Department of Commerce.
systems because internal stations may not be individually
2.4 Acronyms:
contained in the DMS and, as a result, will not be displayed by
2.4.1 ACD—automatic call distributor.
ANI or ALI equipment.
2.4.2 ALI—automatic location identification.
2.2.54 public safety agency, n—an entity that provides
2.4.3 ANI—automatic number identification.
firefighting, law enforcement, emergency medical, or other
2.4.4 CO—central office.
emergency service.
2.4.5 CAD—computer-aided dispatch.
2.2.55 public safety answering point (PSAP) attendant,
2.4.6 CPE—customer premises equipment.
n—a person responsible for answering incoming 9-1-1 calls at
2.4.7 DMS—data management system.
a PSAP, determining the action to be taken, and executing the
2.4.8 ESN—emergency service number.
PSAP’s procedures in the disposition of such calls.
2.4.9 ESS—electronic switching system.
2.2.56 public safety answering point (PSAP), n—a facility
2.4.10 ESZ—emergency service zone.
equipped and staffed to receive 9-1-1 calls. A primary PSAP
2.4.11 FX—foreign exchange.
receives the calls directly; if the call is relayed or transferred
2.4.12 MSAG—master street address guide.
the next receiving PSAP is designated a secondary PSAP.
2.4.13 PBX—private branch exchange.
2.2.57 public switched telephone network (PSTN), n—the
2.4.14 PSAP—public safety answering point.
totality of equipment, lines, and controls assembled to establish
2.4.15 PSTN—public switched telephone network.
communication paths between calling and called parties.
2.4.16 UPS—uninterruptible power system.
2.2.58 ring back, n—the capability permitting a PSAP
attendant to cause the telephone on a held circuit to ring. Also 3. Significance and Use
known as re-ring.
3.1 This guide recommends approaches for planning and
2.2.59 selective routing, n—the capability of routing a 9
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