This xDSL Glossary is 1996 Todd Ogasawara

Reproduction of the glossary is not permitted without prior permission from the copyright holder.

xDSL Glossary of Terms


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z #

Select the first letter of the word from the list above to jump to appropriate section of the glossary. If the term you are looking for starts with a digit or symbol, choose the '#' link.


- A -

aardvark
Animal commonly referred to as an "ant-eater."
 
ADSL
Asymetric Digital Subscriber Line. 1.5 to 9Mbps downstream. 16 to 640Kbps upstream.
 
ATM
Asynchronous Transfer Mode.
apple
A popular fruit.
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- B -

 
bit
A contraction for BInary digiT. A bit has only two states: Off or on (0 or 1).
 
byte
A data length unit consisting of 8 bits with a value range from 0 to 255 (28-1).
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- C -

Cable Modem
This device is not really a modem in the modulator-demodulator sense. It is a device that uses Cable TV fiber/coax transport facilities to deliver Ethernet-like data network services.
 
CAP
Carrierless Amplitude Phase. One of two methods used to provide ADSL. See also DMT.
 
CPE
Customer Premise Equipment.
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- D -

 
DirecPC
A satellite based service from Hughes Network Systems that delivers an extremely asymetric bandwidth service. The downstream data from the satellite to the user's satellite dish is 400Kbps. The upstream data is sent using a POTS based analog modem limited to 33.6Kbps (V.34 Annex 12).
 
DMT
Discrete MultiTone. One of two methods used to provide ADSL. See also CAP.
 
downstream
Data moving from the head-end source to the customer. See also upstream.
 
DSLAM
Digital Subscriber Line Access Multiplexer.
 
DWMT
Discrete Wavelet MultiTone. A cable modem modulation scheme. See also QPSK.
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- E -

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- F -

FDM
Frequency Division Multiplexing
 
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- G -

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- H -

 
HDSL
High-data-rate Digital Subscriber Line. 1.544Mbps using two twisted pair lines. 2.048Mbps using three twisted pair lines.
 
HFC
Hybrid Fiber Coaxial.
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- I -

 
IEEE
Institute for Electronic and Electrical Engineers.
 
IETF
Internet Engineering Task Force.
 
IPng
Internet Protocol next generation.
 
ISDN-BRI
Integrated Services Digital Network-Basic Rate Interface.
 
ITU
International Telecommunications Union.
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- K -

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- L -

LAN
Local Area Network. See also WAN.
 
LMDS
Local Multipoint Distribution Service. A broadband wireless technology that provides two-way digital broadcasting using ground based tranceivers instead of satellites.
 
Local Loop
The
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- M -

 
Mbps
Megabits per second. This is the usual unit of measure for network speed. Note that it is measuring the throughput of millions of bits and not bytes per second.
 
MPEG
Motion Pictures Expert Group.
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- N -

 
NIC
Network Interface Card.
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- O -

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- P -

 
POP
Point Of Presence.
 
POTS
Plain Old Telephone Service.
 
PSTN
Public Switched Telephone Network
 
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- Q -

 
QAM
Quadrature Amplitude Modulation.
 
QPSK
Quadrature Phone Shift-Keying
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- R -

 
RADSL
Rate Adaptive Digital Subscriber Line. 600Kbps to 7Mbps (or 32Kbps to 8Mbps) downstream. 128Kbps to 1Mbps (or 64Kbps to 1Mbps) upstream. RADSL permits simultaneous voice and data communications with little impact on data throughput.
 
RBOC
Regional Bell Operating Company. Any of the independent regional telephone companies (Baby Bells) that were formed after the breakup of AT&T in 1984. Ameritech, Bell Atlantic/Nynex (now merged), Bellsouth, SBC/Pacific Telesis (now merged), US West.
 
RG
Residential Gateway. An intelligent crossconnect device that provides termination for all access networks to the home as well as termination for all home networks (telephones, televisions, alarms, etc.).
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- S -

 
SDSL
Single-line Digitial Subscriber Line. 1.544 or 2.048Mbps on a single line pair.
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- T -

T1E1.4
The ANSI committee in charge of ADSL standards.
 
10Base-T
A type of ethernet that uses unshielded twisted pair cable.
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- U -

upstream
Data moving from the subscriber to the head-end. See also downstream.
 
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- V -

 
VDSL
Very-high-data-rate Digital Subscriber Line. 13 to 52Mbps downstream. 1.5 to 2.3Mbps upstream.
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- W -

WAN
Wide Area Network. See also LAN.
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- Y -

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Revised: March 17, 1997.
Copyright 1996 by Todd Ogasawara
All trademarks or product names mentioned herein are the property of their respective owners.