An SS7 signaling link between a
Signal Transfer Point (STP) and either a telephone switch
or a Service Control Point (SCP).
A feature that permits
the calling party to dial the destination telephone number in fewer than
normal digits. Abbreviated Dialing numbers must be
set up in advance of their use. Speed
Dialing is a
typical example of Abbreviated Dialing.
The method, time, circuit, or
facility used to enter the network.
Access Code - AC
A short sequence of digits
allowing a user to access a specific facility, service, feature or
function of a telecommunications network or computer
The design, ordering,
installation, pre service testing, turn-up and maintenance on local
The circuit used to enter
the communications network.
Switching equipment, usually
placed in large buildings with multiple customers or at a single
customer premise, and designed to handle large
volumes of calls.
Access Tandem - AT
A LEC switching system
that provides a traffic concentration and distribution function for
inter-LATA traffic originating or terminating with a
LATA. The access tandem provides the
access to more than one end office within the LATA. More than one access
may be required to provide access to all end
offices within a LATA.
Also known as Project Codes
or Bill-Back Codes. Account Codes are additional digits dialed
by the calling party that provide information
about the call. Typically used by hourly professionals
(accountants, lawyers, etc.) to track and bill
clients, projects, etc.
ACNA - Access Carrier Name
This is how a telecommunications
company is identified to others like it. Used on all access
service requests when ordering service from the
LEC. (e.g. Electric Lightwave's ACNA is "ELG")
There can be multiple CICs per ACNA.
ACTL - Access Customer Terminal Location
Identifies the COMMON LANGUAGE location where an Interexchange Carrier (IC)
are terminated for connection to
an Exchange Carrier (EC) for Access Services. For a CLLI to be an
it must end in (x)MD or W(x)(x) with
"x" being any number or letter.
A 32-bit long mask used to
select an IP address for subnet addressing. The mask selects the
network portion of the IP address and one or
more bits of the local LAN address.
The process of
converting external addresses into standardized network addresses and vice
versa. Facilities interconnection of multiple
networks which each have their own address plan.
A person or organization that acts on
behalf of another. In the telecommunications industry,
Agents typically are independent individuals or
companies that market the services of a carrier
they were employees of that carrier.
A discount applied
to multiple services based on the total dollar value of those services.
An independent entity that
brings several subscribers together to form a group that can obtain
long-distance service at a reduced rate.
Subscribers are billed by the original IXC. The aggregator
only provides the initial set-up of the plan. He
usually provides no service after that. Different than
AIN - Advanced Intelligent Network
dynamic database used in Signaling System 7. It supports advanced features
processing the call based upon
trigger points throughout the call handling process, and feature
components defined for the originating or
terminating number. Offers one way for a network element
to query a central database to obtain local number
portability routing information.
AIOD - Automatic Identified Outward Dialing
An option on a PBX that specifies the extension number, instead of the PBX
number on outward
calls (for internal billing).
Alarm indication signal usually all
ones--F11111111. Also known as a Blue Alarm which signals
that an upstream failure has occurred.
A real-time indication or signal of
an abnormal situation or event, which triggers an audible, visual
or other indication that there is a problem
with telecommunications equipment, facilities or building
environment. Usually includes a Priority
or Severity Code.
A form of local access
where the provider is not the LEC, but is authorized or permitted to provide
Alternate Access Carriers
carriers in direct competition with the RBOCs. Normally found only in the
metropolitan areas. Examples are
Teleport and Metropolitan Fiber Systems.
Alternate Mark Inversion - AMI
A line code
used for T-1 and E-1 lines that has a 12.5% ones density minimum, and the
conditions of the signal alternate between
positive and negative polarity.
Alternative Operator Services - AOS
Operator services provided by a company other than a LEC RBOC or AT&T
that is authorized
to provide such service.
AMA - Automatic Message Accounting
automatic collection, recording and processing of information relating to
calls for billing
An electrical signal that
varies continuously in amplitude and frequency and usually carries
Charges for supplementary
services comprised of optional features, which may consist of both
non-recurring and monthly charges.
supplementary, sub component characteristics and capabilities. Marketing
of Products and Services.
ANI - Automatic Number Identification
(1) The number associated with the
telephone station(s) from which switched calls are originated
software feature associated with Feature Group D (and optional on Feature
Group B) circuits.
ANI provides the originating
local telephone number of the calling party. This information is
transmitted as part of the digit stream in the
signaling protocol, and included in the Call Detail
Record for billing purposes.
(3) ANI may also be used
to refer to any phone number.
ANSI - American National Standards Institute
A United States-based organization which develops
standards and defines interfaces for
indication sent back to the originating end when the called station answers.
Application Program Interface - API
Programmatic interface used for interprogram communications or for
interfacing between protocol
The specifications of a system
and how its subcomponents interconnect, interact and cooperate.
Architectures are often described in multiple
levels of abstraction from low-level physical to higher-level
logical application and end-user views.
Area Code Routing
Route calls based
on the originating ANI NPA (area code). See NPA-NXX Routing.
Area of Service - AOS
The geographical area
supported by a communication service. For 800 numbers, if AOS is
is using Complex Call
ARP - Address Resolution Protocol under TCP/IP
Used to dynamically bind a high level IP address to a
low-level physical hardware address. ARP is
to a single physical network that supports hardware broadcasting.
ART - Advanced Radio Technology
that provides the use of a microwave dish installation at the customer's
site to avoid the
LEC portion of a local loop, and
connects directly into ELI's network.
ASCII - American Standard Code for Information Interchange
A uniform code used in computer and data
communications systems, which employs seven binary
digits (bits) to represent all letters, numbers, punctuations and special
characters, plus one parity bit
used in checking for
ASR - Access Service Request
A document (or
data transaction) sent to the LEC, CLEC, or IEC/IXC to order the local
(loop) portion of a circuit.
Asynchronous (i.e. Not Synchronous)
of concurrent input and output communication transmission with no timing
between the two signals.
Slower-speed asynchronous transmission requires start and stop bits
to avoid a dependency on timing clocks (10 bits
to send on 8-bit byte).
Asynchronous Transfer Mode Adaptation Layer - AAL
A series of protocols enabling ATM to be made
compatible with virtually all of the commonly used
standards for voice, data, image and video. AAL-1 = Functions in
support of constant bit rate,
such as voice and video. AAL-2 = A place holder for variable bit
transmission. AAL-3/4 = Functions in
support of variable bit rate, delay-tolerant data traffic requiring
some sequencing and/or error detection support.
AAL-5 = Functions in support of variable bit rate,
delay tolerant connection-oriented, and connectionless, which have been
ATM - Asynchronous Transfer Mode
international ISDN high-speed, high-volume, packet-switching transmission
ATM uses short, uniform,
53-byte cells to divide data into efficient, manageable packets for
switching through a high-performance
communications network. The 53-byte cells contain 5-byte
destination address headers and 48 data bytes. ATM is
the first packet-switched technology designed
from the ground up to support integrated voice, video, and data
communication applications. It is
to high-speed WAN transmission bursts. ATM currently accommodates
from 64 Kbps to 622 Mbps. ATM may
support gigabit speeds in the future.
A loss of signal strength in a
lightwave, electrical or radio signal usually related to the distance
the signal must travel (e.g. fiber optic transmission
must be regenerated approx. every 30 miles).
optic attenuation is caused by transparency of the fiber, bending the
fiber at too small of a
radius, nicks in the fiber,
splices, poor fiber terminals, FOTs, etc.EDOA), Electrical attenuation
is caused by the resistance of the conductor, poor
(corroded) connections, poor shielding, induction,
RFI, etc. Radio signal attenuation may be due to atmospheric conditions, sun
design / positioning, obstacles,
AuthCode - Authorization Code
A number used
for security purposes to gain access to an Interexchange Carrier's network.
Authorization codes are inherently required for
all Feature Group-A and Feature Group- B
without ANI reporting. Authorization codes are also required for
Travel Service and
Cut-Through capabilities on
Feature Group-D circuits.
Automatic Call Distribution - ACD
which allows automated routing and reporting of calls for customers with
or locations. A system
designed to evenly distribute heavy incoming call traffic among multiple
Automatic Location Identification
feature by which the name, address and responding agencies associated with
of the telephone, used to dial 911, is
displayed at the PSAP at the time the call is answered.
Automatic Ring Down - ARD
A private line
connecting a station instrument in one location to a station instrument in a
location with automatic two-way
signaling. The automatic two-way signaling used on these circuits
causes the station instrument on one end of the
circuit to ring when the station instrument on the
other end goes off-hook. This circuit is sometimes called a
"hot-line" because urgent communications
are typically associated with this service. ARD
circuits are commonly used in the financial
May also have one way signaling. Station "A" rings Station
"B" when Station "A" goes
hook, but Station "B" cannot ring Station "A".