Download Connects` Glossary of Telecommunications Terminology

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A General Glossary of Telecommunications Terminology
Analog – Electronic transmission of voice and data accomplished by adding signals of
varying frequency, or amplitude, to carrier waves of a given frequency of alternating
electromagnetic current. Dial-up modems utilize analog transmission techniques.
Asymmetrical Digital Subscriber Loop (ADSL) – One of the two-wire, copper-based
Digital Subscriber Line (DSL) technologies which utilizes most of the available channel
bandwidth above 4 KHz path to transmit and receive data. It is asymmetric in that it
uses most of the available channel bandwidth to transmit downstream to the user and
only a small part to receive information from the user.
Asynchronous Transfer Mode (ATM) – ATM is a layer 2, cell-based, fast-packet
networking technology that provides a protocol for transmitting voice , data, and video
applications over high-speed networks with access ports beginning at 1.5 MB/s through
OC-12. ATM is a connection-oriented technology used in both Local Area Network
(LAN) and Wide Area Network (WAN) environments that utilizes a fixed cell size of 53
octets for transmission across the network, and provides various qualities of service
depending on the application’s needs.
Backbone - A network element with a central cabling scheme and/or high speed
connections linking multiple network nodes.
Bandwidth – The transmission rate or the amount of data that can be transferred over
a specific connection. High speed connections usually range from at least 256 KB/s per
second to more than 10 GB/s per second.
Bit - Short for binary digit, the smallest unit of information on a machine. A single bit can
hold only one of two values: 0 or 1. A byte is composed of eight consecutive bits.
Bits per second (Bps) - Abbreviation of bits per second, the standard measure of
digital data transmission speeds.
Broadband - Refers to telecommunication that provides multiple channels of data,
voice and video over a single communications medium, typically using some form of
frequency or wave division multiplexing. When referring to Connect efforts, broadband
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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is minimally defined as symmetrical 1.5 MB/s or asymmetrical > 1MB/s downstream and
384K upstream.
Broadband over Power Lines (BPL) – An overlay technology that allows Internet data
to be transmitted over low and medium voltage utility power lines.
Cable (Television) Modem – A device that is designed to allow the transmission of
data over coaxial cable television lines to achieve fast access to the Internet and
provide an Ethernet user interface. Cable Modems utilize an industry standard protocol
called Data Over Cable Service Interface Specification (DOCSIS). Similar to
Asymmetrical Digital Subscriber Loop (ASDL), cable modems can offer asymmetrical
transmission rates of up to 6+ Mbps downstream and up to 384 KB/s upstream
depending on network configuration.
Central Office (CO) – Typically a telephone company building where subscriber lines
(local loops) are connected to network switching equipment. The Central Office has
voice and data switching equipment that can switch calls and networks locally or to
long-distance carrier phone and data lines. It also provides a collocation space for other
service providers such as a Competitive Local Exchange Carrier (CLEC).
Coaxial Cable – A transmission cable composed of an insulated central conductor
wrapped in another cylindrical conductor and then wrapped an another insulating, outer
protective layer. Coax has the capacity to support very high bandwidth transmission
rates.
Competitive Local Exchange Carrier (CLEC) - A telecommunications service provider
that competes with an Incumbent Local Exchange Carrier (ILEC) such as a Regional
Bell Operating Company (RBOC) like Verizon to deliver similar access services.
Dial-Up Connection – Analog modem technology that uses an existing local telephone
line and is limited to the 400 Hz to 4 KHz frequency range and provides transmission
rates between 2.4 KB/s and 56 KB/s.
Digital – Electronic technology that generates, stores, and processes data in terms of
two states: positive is represented by the number 1 and non-positive by the number 0.
Thus, data transmitted or stored with digital technology is expressed as a string of 0’s or
1’s. Each of these state digits is referred to as a bit.
Digital Subscriber Line (DSL) - A copper-based technology for providing continuously
available ("always on") high-bandwidth connection utilizing existing copper telephone
lines. Various types of DSL include Asymmetric Digital Subscriber Line (ADSL) a twowire service, and High-bit-rate Digital Subscriber Line (HDSL) a four-wire service (see
HDSL). ADSL is asymmetric in that it uses most of the channel to transmit downstream
to the user and only a small part to receive information from the user. Assuming the
home or small business is close enough to a telephone company central office that
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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offers DSL service, it may be able to receive data at rates up to 6.1 MB/s megabits
(millions of bits) per second. Typically, individual connections will provide from 768 KB/s
to 3 MB/s downstream and about 128 KB/s upstream. A DSL line can carry both data
and voice signals and the data part of the line is continuously connected to the network.
A DSL line is limited by line quality and distance from the Central Office. Depending on
the Digital Subscriber Line Access Multiplier (DSLAM) equipment and the line quality,
DSL service often may not reach past 20,000 cable feet from the Central Office.
Digital Subscriber Line Access Multiplier (DSLAM) – The switching equipment
located in the Central Office or Remote Terminal that allows for Digital Subscriber Line
(DSL) service to subscribers. Not all Central Offices are equipped with DSLAMs.
Ethernet – (1) a baseband local area network specification invented and developed
jointly by Xerox, Intel, and Digital Equipment Corporation. Ethernet networks operate at
10, 100, and 1000 MB/s using Carrier Sense Multiple Access / Collision Detect
(CSMA/CD) to run over coaxial, Cat.5, or fiber optic cables; (2) a very common and
most preferred method of networking computers in a LAN environment.
Fiber Optic Cable - A transmission medium that uses long, thin strands of glass or
plastic fibers, rather than copper wire, to transport data or voice signals. The signal is
imposed on the fiber via pulses (modulation) of light from a laser or a light-emitting
diode (LED). Because of its high bandwidth and lack of susceptibility to interference,
fiber optic cable is used in long-haul and local distribution networks.
Fiber to the Premises (FTTP) – A telecommunications networking service that utilizes
fiber to each subscriber to deliver high bandwidth services.
Frame Relay (FR) - A layer 2, connection-oriented, packet-switching protocol for
connecting devices on a Wide Area Network (WAN). It used Permanent Virtual Circuit
(PVC) technology to create point to point, full, and partial mesh connections between
FR network nodes. FR networks in the U.S. support data transfer rates at 56 KB/s
through 45 MB/s. FR utilizes existing DDS, T-1, and T-3 lines owned by a service
provider.
Gigabits Per Second (GB/s) – A digital transmission speed of a billion bits per second.
Gigahertz (GHz) – An analog transmission speed of a billion cycles per second.
High-bit-rate Digital Subscriber Line (HDSL) – A four-wire, symmetrical, copperbased Digital Subscriber Line (DSL) technology with the same upstream and
downstream speeds. It has comparable speed to a T-1 and is the most common local
loop technology deployed by the local service providers to deliver T1s.
Hertz (Hz) – The speed or frequency of cycles in an analog transmission.
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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Hotspot – An access point for a short-range, public wireless broadband access that is
often located in populated areas, such as airports, libraries, or hotels.
Hub – The intelligent wiring center to which all devices, printers, scanners, PCs, etc. are
connected within a segment of a local area network (LAN).
Incumbent Local Exchange Carrier (ILEC) - A telecommunications service provider
such as a Regional Bell Operating Company (RBOC) like Verizon.
Integrated Services Digital Network (ISDN) - A set of standards for digital
transmission over ordinary telephone copper wire or other media. Home and business
users who install an ISDN adapter (in place of a modem) can achieve transmission
speeds up to 128 KB/s. ISDN specifies three distinct transmission channels referred to
as 2B+D. There are two 64 KB/s “bearer channels” for data transmission which can be
bonded to achieve 128 KB/s, and a 16 KB/s data channel for line control.
Internet Service Provider (ISP) – A company that provides access to the Internet to
subscribers for a fee.
Kilohertz (KHz) – A measure of analog transmission speed of a thousand cycles per
second.
Kilobits Per Second (KB/s) - A measure of digital transmission speed of a billion bits
per second.
Local Area Network (LAN) – A network of devices, such as computers, printers and
scanners, connected by wires or wireless for a small area, such as a floor, department
or small cluster of buildings. A system of LAN’s connected are called a Wide Area
Network (WAN).
Last-mile technology (also known as “First-mile technology”) - Any
telecommunications technology, such as wireless radio, that carries a signal from the
local Central Office along the relatively short distance (hence, the "last mile") to and
from the home or business, telecommunications infrastructure at the neighborhood
level. In many communities, last-mile technology represents a major challenge to highbandwidth applications such as fast Internet access, with web pages full of multimedia
effects, videoconferencing, etc.
Local Multipoint Distribution Services (LMDS) - Fixed wireless technology that
operates in the 28 GHz band and offers line-of-sight coverage for distances up to 3 to 5
kilometers. At a maximum, it can deliver data and telephony services to 80,000
customers from a single node. LMDS is considered one possible solution for bringing
high-bandwidth services to homes and offices within the "last mile" of connectivity, an
area where cable or optical fiber may not be convenient or economical.
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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Local Exchange Carrier (LEC) - The term for the public telephone company in the U.S.
that provides local service. Some of the largest LEC are the Bell Operating Companies
(BOC) which were grouped into holding companies known collectively as the Regional
Bell Operating Companies (RBOC) when the Bell System was broken up by a 1986
Consent Decree.
Local Loop - The link between the subscriber's equipment and the line-terminating
equipment in the telephone exchange.
Metropolitan Area Network (MAN) – A group of data devices that can communicate
with each other within a city or a large campus area covering many city blocks.
Megabits per Second (MB/s) - A measure of digital transmission speed of a million bits
per second.
Megahertz per Second (MHz) – A measure of analog transmission speed of a million
cycles per second.
Multi-channel/Multi-point Microwave Distribution System (MMDS) - A wireless
broadband technology for voice, data, video or Internet access over licensed and
unlicensed channels, with channels in 6 MHz allotments.
Node - The point at which a piece of user equipment connects to the network.
Packet - A group of data and control bits that is transmitted as a unit.
Plain Old Telephone Service (POTS) – Refers to the standard telephone service in
most homes.
Point-to-Point – Network architecture that allows the transmission of data between two
locations.
Point-to-Multipoint - A communications network that provides a path from one location
to multiple locations (from one to many).
Points of Presence (POP) - A term used by Internet service providers to indicate the
number of geographical locations from which they provide access to the Internet.
Remote Terminal (RT) – An extension of Central Office switching equipment. The
location at which there is a transition between a telecommunications common carrier
and the local lines serving the individual customers.
Quality of Service (QoS) - Term for the set of parameters and their values which
determine the performance of a given circuit or network.
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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Satellite Technology - Electronic communication via a satellite link. Satellite networks
are composed of a hub, satellites and receiving antennas on dishes.
Served Community – A municipality that has access to Digital Subscriber Line (DSL)
and cable broadband technologies.
Symmetrical Digital Subscriber Line (SDSL) – One of the two-wire, copper-based
Digital Subscriber Line (DSL) technologies that provides identical data transmission
rates both downstream and upstream (transmit & receive).
Synchronous Optical NETwork (SONET) – A family of standard fiber optic
transmission rates from 51.84 MB/s to 39.812 GB/s created to provided the flexibility to
transport many digital signals with varying capacities and provide a transmission d esign
standard above 45 MB/s. SONET architectures allows for the drop and insert capability
between various SONET network nodes, as well as a ringed design which provides
network service redundancy in the case of a fiber break.
T-1/T-Carrier System – Also known as DS-1, this technology can be used to transmit
voice, data, video and Internet. The T-carrier system uses four copper wires to provide
duplex capability (two wires for receiving and two for sending at the same time). It
supports a symmetrical bandwidth of 1.544 MB/s. The T-1 digital stream can be used
as a unified transmission pipe for a single network port or can be used for voice
transmission supporting 24 64-KB/s channels/paths.
TCP/IP - Internet Protocol (IP) / Transport Control Protocol (TCP) – A combination
of protocols that makes up the Internet’s networking protocol. IP is a layer 3
connectionless protocol that, when combined with TCP, a layer 4 connection-oriented
protocol, provides reliable transmission of packet data over IP networks .
Triple Play – A three-way service bundle of voice and/or Voice over Internet Protocol
(VoIP) services, broadband Internet access, and cable television/video-on-demand
services.
Trunk - In telephone systems, a line that carries multiple voice or data channels
between two Central Office switching systems. In digital communications, a trunk is
often a T-carrier system.
Unbundled Network Elements (UNE) – Parts of the telecommunications network that
Incumbent Local Exchange Carriers (ILEC) are required to offer for sale through a
collocation agreement to Competitive Local Exchange Carriers (CLEC) on an
unbundled basis as defined by the Telecommunications Act of 1996.
Underserved Community - A municipality that has very limited access to Digital
Subscriber Line (DSL) and/or cable broadband technologies.
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com
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Unserved Community - A municipality that does not have access to Digital Subscriber
Line (DSL) or cable broadband technologies.
Voice over Internet Protocol (VoIP) – This technology allows voice conversations to
be carried over the Internet as opposed to traditional phone lines.
WDM (Wavelength Division Multiplexing) - WDM is a fundamental passive optical
component for optical system sending several signals through one WDM with different
wavelengths of light. There are two distinct WDM architectures, CWDM and DWDM.
CWDM (Coarse Wavelength-Division Multiplexing) allows eight or fewer channels to be
stacked in the 1550 nm region of optical fiber, the C-Band. DWDM (Dense WavelengthDivision Multiplexing) is able to transmit many of closely spaced wavelengths in the
1550 nm (nanometers) region over a single optical fiber. Wavelength spacings are
usually 100 GHz or 200 GHz.
Wide Area Network (WAN) - A network which encompasses interconnectivity between
devices over a wide geographic area.
Wireless Fidelity (WiFi) – Term used to describe any wireless network that connects
users to an access point using an 802.11 a/b/g (WiFi speeds) standard network.
Wireless LAN (WLAN) - In which a mobile user can connect to a Local Area Network
(LAN) through a wireless (radio) connection. A standard specifies the technologies for
wireless LANs, which includes an encryption method.
Worldwide Interoperability for Microwave Access (WiMax) – Broadband wireless
networks that are based on the Institute of Electrical and Electronics Engineers, Inc
(IEEE) 802.16 standard, which ensures compatibility and interoperability between
broadband wireless access equipment.
Wireless Mesh Network (WMN) – A Wireless Local Area Network (WLAN) that has
redundant connections among multiple nodes and users.
Wireless Internet Service Provider (WISP) – A company that provides Internet access
to subscribers for a fee over a wireless connection.
Sources: Definitions from 2001 Flack & Kurtz, Inc. Report; Definitions from 2006 Harry Newton; Newton’s Telecom
Dictionary, 22nd Edition, CMP Books; The Essential Guide to Telecommunications, 3rd Edition, Annabel Z. Dodd
Online resources: Webopedia.com; IEC.org; FCC.gov; lastmileonline.com