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3DES
Triple Data Encryption Standard

AAC
A Dolby audio compression scheme, IEC standard 13818-7 for MPEG-2, and IEC
14496-3 for MPEG-4.

AAL5
ATM Adaptation Layer Five. An encapsulation of packets into ATM  frames. ITU-T
Recommendation I.363, March 1993. Connection oriented but variable bit rate, often
used for IP datagrams.

AC-3
Dolby Digital Surround Sound. Five audio channels plus sub woofer. Sometimes
called 5.1 channels. Used for NTSCDVD-Video.

Access Rate
The speed, in bits per second, at which data is transmitted between the
end user and the network.

Adaptive Equalization
Receiver technique that compensates for distortions in
transmission media.

ADC
Analog to Digital Converter

ADSL
Asymmetric Digital Subscriber Line. Offers higher download speed than upload
speeds and is usually configured to deliver up to six megabits(Mbps) of data
per second.

ADM
Add Drop Multiplexor. Splits out part of a SONET link.

ADPCM
Adaptive Differential Pulse Code Modulation. Popular audio encoding (telephone
quality at 32 Kbps).

ADSL
Asymmetric Digital Subscriber Line. Twisted-pair modem technology that achieves
data rates of up to 8 Mbps downstream to the subscriber, and up to 1 Mbps upstream
to the network at distances up to 18,000 feet.

AFD
All Format Decoder

AFE
Analog Front End

AGP
Accelerated Graphics Port. Located on new PCs between CPU and display controller.

AGT
A force of substance that causes change.

Aggregator
Any number of services or systems that aggregate particular items for
convenient use by customers.

AID
Access Identifier. Start of Tut HomeRun packet, for collision detection.

Analog Decoder
A circuit that performs decoding using analog circuit techniques rather
than digital circuit techniques.

ANSI
American National Standards Institute

API
Application Programming Interface.  A specification of a software interface, usually
in terms of data structures and function declarations.

APS
Analog Protection System. Prevents easy piracy, such as Macrovision, which
prevents analog copies on VHS tapes.

ARL
Acceptable Reliability Level

ARQ
Automatic Repeat reQuest. Using link level sequence numbers for retransmission.

ASD
Advanced Streaming Descriptor. NetShow encoder config files.

ASIC
Application Specific Integrated Circuit.

ATAPI
AT Attachment Packet Interface

ATL
Active Template Library

ATM
Asynchronous Transfer Mode. A family of specifications for network connection at
speed like 155 Mbps, 622 Mbps, and higher. Based on tiny cells, assembled into
frames or bit streams.

ATSC
Advanced Television Systems Committee

ATU
ADSL Transceiver Unit. ATU-C is the central office end, and ATU-R the “remote”
(subscriber) end.

AV
C / Audio Video Control, (part of 1394).

AVT
Audio Video Transport

Backbone
/ A central very high-speed, fiber network transmission path used for
high-volume network-to-network connections.

Back Channel
A means of communication from users to content providers.

Bandwidth
The range of frequencies of interest on a channel.

BAR
Base Address Register.

BASCS
Broadcom Advanced Server Control System.

BASP
Broadcom Advanced Server Program.

BCC
Binary Convolutional Code

BEB
Binary Exponential Backoff. Collision resolution on Ethernet.

BIST
Built In Self Test

BORSCHT
Battery, Over voltage, Ringing, Supervision, Coding, Hybrid, Test

BPS
Bits per second. The number of bits passing a point every second.

Broadband Communications
Data transmissions at speeds of greater than 1.5 Mbps.

BRI
Basic Rate Interface. The basic unit of ISDN service, usually 56 Kbps or 64 Kbps.

Bridge
A device that connects two networks as a seamless single network using the same
networking protocol.

Cable Modem
A data modem that uses the bandwidth within a cable TV system, which can
have speeds up to 80 times faster than an ISDN line or six times faster
that a dedicated T1 line.

Cache
Local or temporary storage.

CAP
Carrierless Amplitude and Phase. Also called Carrierless AM/PM (Amplitude
modulation and phase modulation). A modulation scheme for xDSL that shipped
earlier than the official standard DMT. The notation n-CAP means log2(n) bits
per baud.

Carrier Hotel
Collocation involves companies – either Incumbent Local Exchange Carriers
(ILECs) or independent firms — providing space to house
telecommunications equipment.

CASE
Computer Aided Software Engineering, Common Application Service Element.

CBC
Cipher Block Chaining. A mode of DES.

CBDong
Card Bus “Dongle” board, with magnetics and LED.

CBNIC
CardBus Network Interface Card reference board.

CBR
Constant Bit Rate, committed bandwidth reservation.

CCD
Charge Coupled Device. Common digital camera technology.

CDU
Circular buffer Data Unit

CDV
Processing of data stream to greatly reduce(compress) the data bandwidth required
to transmit video images.

CEBus
Consumer Electronics Bus. “Standard” powerline net, about 10 Kbps.

Cell
53 byte units switched by ATM technology.

CES
Consumer Electronics Show

CFID
ConFiguration IDentifier (device and vendor ids for a PCI device).

CHAP
Challenge Handshake Authentication Protocol. For PPP link (usually Dial-In)
security.

CIF
Common Interchange Format. A popular video encoding, often 352×288 pixels, about
half of CCIR-601.

CLEC
Competitive Local Exchange Carrier.

CLSID
Class Identifier. String of hex numbers for ActiveX.

CMIC
Cable Modem Information Center, configuration Management Information Center.ISO
proposal for network management.

CMIP
Common Management Interface and Protocol. ISO proposal for network management.

CMOS
Complementary Metal Oxide Semiconductor. Technology used to manufacture silicon
integrated circuits.

CMTS
Cable Modem Termination System. The cable headend device which serves as a
bridge between a DOCSIS cable data modem and the internet.

CNIC
Composite Network Interface Card. An AFE  in 2-3.5 MHz band (1.25 MBaud), plus
Galileo and FPGAs, codecs and discrete analog components.

CO
Central Office. Of a local exchange carrier, the local “phone company”.

COFDM
Coded Orthogonal Frequency Division Multiplexing

Codec
Coder and Decoder. In hardware, the chips that convert analog to digital samples
and convert digital samples to analog.

CRA
Collision Resolution Algorithm

CRC
Cyclic Redundancy Check

Crop
Clipping, or removing parts of video that are not displayed.

CSM
Chartered Semiconductor Manufacturing.

CSMA
CD / Carrier Sense Multiple Access with Collision Detection. Ethernet Media
Access Control algorithm.

CSS
Content Scrambler System. Encryption scheme for DVD. Also Cascading Style Sheet
(HTML).

CWDM
Coarse Wave Division Multiplexing.

DAC
Digital-to-Analog Converter

D1
Uncompressed Digital Video and Audio standard used to master movies. Resolution
is 480 lines by 720 pixels.

DA
Destination Address

DAC
Digital to Analog Converter

Dark Fiber
Unused fiber optic cable, sometimes referred to as “unlit glass.”

DASE
Digital TV Application Software Environment

DAVIC
Digital Audio Visual Council

DBC
Data-parallel bit-serial C

DBS
Digital Broadcast Satellite. A broadband communications technology that broadcasts
digital television programming from satellites directly to dish antennas.

DCT
Discrete Cosine Transform. A technique for compressing images by converting them
into the frequency domain. Used in JPEG, MPEG, and H.261.

Digital Broadcasting
Digital terrestrial television over-the-air broadcasting using CDV.

DCOM
Distributed Component Object Model. Microsoft COM follow-on.

DDK
Device Driver Kit. Some DDK’s are OS-specific (Windows 95, NT 4.0, NT 5.0, 98, CE)
others are device class-specific.

DDFS
Dynamic Device File System. DDFS is an architecture which requires a driver to
support a combination of a particular host adapter and a particular storage device
or set of devices.

DDS
Digital Data Source, Digital Data System, Dataphone Digital Service.

DECT
Digital Enhaced Cordless Cordless Telecommunication. Phone standard used in SWAP.

DFE
Decision Feedback Equalizer. Digital signal processing technique to determine
equalization based on previous symbol sequence.

DFPQ
Distributed Fair Priority Queuing. Collision resolution algorithm.

DHTML
Dynamic HyperText Markup Language.

Digital Difference
The subtraction of two “signals” (numbers, images, etc.) in the
digital domain.

DirectDraw
Part of DirectX for video rendering.

DLC
Digital Loop Carrier. Combines several local loops into a single T1 line.

DMIF
Delivery Multimedia Integration Framework. MPEG-4 effort for combined audio, video,
web pages, and kitchen sinks, over 28 Kbps modems.

DMT
Discrete MultiTone.  The official T1.413 standard modulation scheme for Digital
Subscriber Line technology (xDSL) patented by Amati (now TI).

DNA
Distributed interNet Applications

DNS
Domain Name Services. Uses name rather than an actual Internet Protocol(IP)
address for simplicity.

Dolby
Company that does many quality audio encodings.

DOM
Document Object Model, web page standard from W3C.

Downstream
Data flowing from the central office (CO) to the subscriber. In technolgies
like ADSL the downstream data rate is significantly higher than upstream.

DRC
Design Rule Check. Performed on a chip before being manufactured.

DSLAM
Digital Subscriber Line Access Module

DS0
Digital Service level zero. Same as BRI,  Equivalent to one telephone call’s worth
of bandwidth.

DSP
Digital Signal Processing

DS1
Digital Service level one. 1.554 Mbps, which can carry 24 telephone calls. A
Physical interface that carries this service is called T1.

DS3
Digital Service level three. About 45 Mbps, or 30 DS1 channels.

DSLAM
Digital Subscriber  Line Access Multiplexer. Concentrates up to hundreds of xDSL
subscribers onto a smaller number of ATM trunk lines.

DSS
Digital Satellite System

DSP
Digital Signal Processing. A signal processing technique that takes real-time, high-
speed signals, such as radio, cellular phones, or satellite TV broadcasts, then
mathematically alters it to improve the signal. This technology includes filtering,
speech recognition, image enhancement, data compression, and noise reduction.

DSPPhy
Coding and decoding data with a Digital Signal Processing chip.

DST
Destination

DSTS
Desktop Support Tracking System

DTLA
Digital Transmission Licensing Authority organization for DTCP.

DTCP
Digital Transmission Content Protection (for 1394).

DTS
Digital Theater System. Audio quality competes with Dolby Digital AC-3.

DTV
Digital Television, includes HDTV and digital versions of SDTV.

DV
Digital Video. Generic term, and a specific DCT protocol for 1394 camcorders.

DVD
Digital Versatile Disc, sometimes Digital Video Disk. Follow-on to CD-ROM, nominal 9
Mbps transfer rate.

D-VHS
A Digital Video format promoted by JVC. Designed to record Digital Broacast
Satellite (DISH) programs and play older VHS tapes.

DVI
Digital Video Interactive. A package of technology from Intel, including some
popular compression formats.

DWDM
Dense Wavelength Division Multiplexing

DWM
Dense Wavelength Division Multiplexing

E-Commerce
Electronic Commerce. Electronic transactions between business and customers
via the Internet.

EBI
External Bus Interface

ECL
Emitter Coupled Logic

Electronic Media Distribution
A method of distributing electronic media, usually as a
download over the Internet.

Enhanced Digital Broadcast
Enhanced Digital Broadcast combines the storytelling of
television with the interactivity of the Web.

ENIC
Board with discrete Analog Front End plus digital chip.

EOF
End Of File, or End Of Frame.

EPAC
Extended Perceptual Audio Coder. With CD quality at 128 Kbps.

EPIC
Electronic Privacy Information Center

Epidiag
TCL front end to simple diagnostics driver.

Epindd
NIC Diagnostic Driver for Epidiag.

Ethernet (10BASE-T)
Networking protocol widely used in local area networks (LANs) for
connecting devices by means of copper twisted-pair wiring at
speeds of 10 Mbps.

FA
Functional Array

Fast Ethernet (100BASE-T)
An extension to the 10BASE-T Ethernet network access method,
Fast Ethernet operates at 100 Mbps.

FCC
Federal Communications Commision

FDQAM
Frequency Diverse Quadrature Amplitude Modulation

FDM
Frequency Division Multiplexing

FEC
Forward Error Correction. A receiver technique for correcting errors in the received
data.

FIB
Focused Ion Beam. Process of making changes to an integrated circuit after
fabrication.

Fiber Channel
A high-speed data link planned to run up to 2 Gbps on a fiver optic cable.

Fiber Optics
A method of data transmission in which data is modulated on to light and is
transmitted at very broad bandwith fibers over very pure, extremely thin
glass fibers.

Fiber-Optic Cable
A cable made of glass fibers that transports data or voice signals.

Filtering
A process used in both analog and digital processing to pass one frequency or
frequency band while blocking others or visa versa.

FIR
Finite Impulse Response. A very useful kind of digital filter.

FireWire
Apple name of what is now the IEEE P1394 standard.

Flow
A sequence of packets that share enough common characteristics (such as source
and destination) that they can be routed the same way, and handled with the same
quality of service policy.

FFE
Feed Forward Equalization

FIFO
First In, First Out

FourCC
Four Character Codes for video pixel formats.

FPBGA
Fine Pitch Ball Grid Array

FPGA
Field Programmable Gate Array. Quick way to make low volume integrated circuits.

FR
Frame Relay. A common service used to connect LANs.

Frame
Unit of data sent between the data link layer and Frame Relay.

FSK
Frequency Shift Keying

FSE
Fractionally Spaced Equalizer

FUNI
Frame User Network Interface. A service on ATM using frames instead of bit streams.

G.dmt
A Proposed xDSL standard using discrete multi tone modulation.

G.hs
AA proposed xDSL standard for negotiation to decide which of all the different
versions are being used on a particular line.

G.lite
The ADSL Forum supports the UAWG’s mission to create a universal, splitterless,
and therefore easy to install lower-speed version of ADSL (G.lite or DSL-lite).

GA
Grand Alliance. 18 digital (including HDTV) standards.

GMIC
Glass Microwave Integrated Circuit

GMII
Gigabit Media Independent Interface

Gps
Giga bits per second. 1,000,000,000 (one billion) bits per second, a measure of
telecommunciatons speed.

GCC
The GNU C compiler.

GDB
The Gnu DeBugger.

Genlock
Synchronizing multiple video sources to the same clock.

GHz
Giga Hertz. One billion cycles per second.

Gigabit Ethernet (1000BASE-T)
An extension to the 100BASE-T Ethernet network access
method which operates at 1,000 Mbps or equivalently 1 Gbps.

Gigabit PHY
Gigabit PHY is the specific description for a PHY operating at 1000Mbps

G.Lite
The new ITU standard that forms the basis of Universal ADSL, which supports
1.5 Mbps downstream and 384 Kbps upstream.

GPIC
GNU version of pic, which is part of the groff document formatting system. pic
compiles descriptions of pictures embedded within troff or TeX input files into
commands that are understood by TeX or troff.

GSM
Global System for Mobile phones.

H.261
A common simple video compression technique, originally used for video
conferencing.

HAVi
Home Audio Video interoperability. A standard for 1394 (Firewire) devices.

HD0
Digital television “standards”, this one favored by Microsoft. Still only
480 lines, but 60 progressive frames instead of interlaced.

Headend
In a local area network, a device that receives signals from each data
station and then retransmits the signals to all the data stations.

HDSL
High Data Rate Digital Subscriber Line. This DSL variety created in the late
1980’s delivers symmetric service at speeds up to 2.3 Mbps in both directions.

HDTV
High Definition Television. Offers six times the resolution of current TV and
a full 60 frames per second temporal resolution which is twice the vertical and
horizontal resolution of current NTSC analog television broadcasting. It also
supports near-CD (compact disc) sound quality.

Headend
The central distribution point in a cable television system. Typically serves
tens to hundreds of thousands of homes.

HFC
Hybrid Fiber Coax. Upgraded cable plant which uses a combination of fiber optic
cable in the backbone and coaxial cable in the subscriber feeder plant.

HMAC
Hashed Message Authentication Code

HPNA
Home Phoneline Network Alliance

HSSI
High Speed Serial Interface (port)

HTML
HyperText Markup Language. The authoring language used to create documents on
the World Wide Web.

IAT
Inter-Arrival Time

IC
Integrated Circuit

idbg
Interactive Debugger

IEEE 802
Local Area Network standards family, wildly successful. Ethernet is
effectively one of them.

IETF
Internet Engineering Task Force

IFG
Inter Frame Gap. Minimum spacing between frames called IPG in 802.

IFMP
Flow Management Protocol. Allows a host to instruct an adjacent node (e.g. an
Ipsilon switch controller) to attach a network layer label to a flow, so
subsequent packets on that flow can be switched in hardware.

ILEC
Incumbent Local Exchange Carrier. The traditional phone company.

INIC
Integrated Network Interface Card. Yet another NIC with custom analog and digital
chips on it.

INICT
INIC board with extra testing features.

Interlaced
Even Lines in one video field, then odd lines, opposite of progressive.

Intserv
The IETF working group on Integrated Services. That is, real time traffic such
as audio and video over the Internet.

IOCTL
Input Output Control

IP
Internet Protocol

IPG     InterPacket Gap

IRP
Input/output Request Packet

IRQ     Interrupt ReQuest

ISA
PC bus (before PCI).

ISDN
Integrated Service Digital Network

ISO
International Standards organization

ISP
Internet Service Provider. A company that provides a subscriber a connection to
the Internet.

ISSLL
Integrated Services over Specific Lower Layers

ITU
International Telecommunications Union. The world telephone standards body.

Java
Sun programming language

JMF
Java Media Framework

JPEG
Joint Picture Experts Group. Usually refers to a DCT image compression standard.

JTAG
Joint Test Action Group, (IEEE Standard 1149.1). Common connector for testing.

Judder
Temporal aliasing artifact of digital video processing. For example, displaying
a 30 frames per second image on a 75 Hz PC monitor.

JVM
Java Virtual Machine

k56flex
A 56 Kbps modem technology developed by Rockwell and Lucent.

Kbps
Kilobits per second. Kilo usually means one thousand. Also written as Kbits/sec
or Kb/sec.

KS
Kernel Streaming interface in Windows Driver Model for video, audio, etc…

L2TP
Layer 2 Tunnel Protocol. Runs the PPP protocol over IP for virtual private nets.

LACP
Link Aggregation Control Protocol

LAN
Local Area Network. A private data communications network linking a variety of
data devices such as computers and printers within an office or home environment.

LANE
LAN Emulation. ATM service for Ethernet bridging.

LE
Linear Equalization

LFSR
Linear Feedback Shift Register

LeapFrog
A VHDL simulator.

LEC
Local Exchange Carrier. The local phone company.

Line 21
Closed captioning standard (displays text at the bottom of video).

LLC
Logical Link Control

LMDS
Local Multipoint Distribution System. A broadband wireless communications network
that uses microwave frequencies around 28 GHz to transmit video and data to
residences over a cellular-like network at distances under a few miles.

Loop
The single pair for wires running from the central office (CO) to each telephone.

LPF
Low Pass Filter

lsb
least significant bit

LVS
Layout versus Schematic

MAC
Media Access Control. Protocol for controlling the upstream and downstream traffic
flow in a local or wide area network.

Macrovision
Analog scheme that discourages making copies of video content on VHS tapes.

MBone
Multicast Backbone

Mbps
Megabits per second. One million bits, and not 1024 times 1024. Also written as
Mbits/sec or Mb/sec.

MCI
Media Control Interface

MD5
Message Digest 5. This is a hash algorithm.

MCNS
DOCSIS / Multimedia Cable Network System / Data Over Cable Service Interface
Specification. Industry specification that defines the technical equipment
for high-speed cable modem and headend equipment.

MDI
Multiple Document Interface, Media Dependent Interface.

MDIX
Media Dependent Interface Crossover

Media Appliances
Consumer electronics devices that feature digital functions,
combining the power of the PC with the convenience of traditional
consumer devices.

MER
Modulation Error Rate

MGCP
Media Gateway Control Protocol

MIB
Management Information Base. The specification of SNMP object numbers for one
specific kind of management agent. The basic IP MIB is often called MIB-II.

MII
Media Independent Interface

Modem
MODulator/DEModulator. Conventional modems comprise equipment which convert
digital signals to analog signals and vice versa.

MQFP
Medium Quad Flat Pack

MII
Media Independent Interface. Replaces 10Base-T Ethernet’s Unit Interface (AUI),
and is used to connect the MAC layer to the physical layer. The MII establishes
a single interface for 100Base-TX, 100Base-T4, and 100Base-FX.

MIME
Multimedia Internet Mail Extension

MIPS
Microprocessor without Interlocked Pipelined Stages.

MMDS
Multichannel Multipoint Distribution Service. A broadband wireless communications
network that uses microwave frequencies around 2.5 GHz to transmit video to
residences at distances up to tens of miles.

Modem
Modulator and Demodulator. Converts between digital data and an analog channel
(such as a telephone line).

MP3
MPEG level 3 audio. Can be used with MPEG-1 or 2 video, or by itself.

MPEG
Moving Pictures Experts Group. Industry standard for compressing and decompressing
digital audio video signals.

MPLS
Multi Protocol Label Switching. IETF technique for large point-to-point networks.

MSAD
Modern Systems Analysis and Design

MSB
most significant bit

MSE
Mean Squared Error

MSI
Microprocessor Slave Interface

Multiplexer
An electronic device that allows multiple channels to be combined into
a single signal.

MUSE
Japanese analog HDTV standard, as opposed to digital ATSC.

NAT
Network Address Translation. Mapping IP addresses across a gateway to avoid
allocating a real block of address space.

NCC
Networking Communications Conference

NCPA
Network Control Panel Applet

NDD
NIC Diagnostic Driver, (replaced by EpiNDD).

NESL
Netware Event Service Layer

NDIS
Network Driver Interface Specification. Version 4.0 in Windows 95 OSR2,
4.1 in NT 4.0, version 5.0 in Windows 98 and NT 5.

NEBS
Network Equipment Building System

NEXT
Near End Cross Talk. A problem with modems over bad wires.

NGIO
Next Generation Input and Output

NIC     Network Interface Card. Plug-in adapter card enables a computer to connect to a LAN.

NID
Network Interface Device. Box between phone line and premise network.

NLE
Non-Linear Editing of video, as opposed to tape.

NPN
Negative Positive Negative

NSR
NIC Sample Recorder

NTSC
Never Twice the Same Color. The US Analog Television standard.

OAM
Operations, Administration, and Maintenance

OC-3
Optical Carrier level three

OC-12
Optical Carrier level twelve. An ATM rate at about 622Mbps.

OFDM
Orthogonal Frequency Division Multiplexing. Used in European digital
television system.

OHCI
Open Host Computer Interconnect. Between IEEE 1394 and a computer.

OID
Number space used in NDIS set and get information calls.

OLE
Object Linking and Embedding

Orca
Optimized Reconfigurable Cell Array

OVS
Open Video System. Scheme to send digital video without proprietary encapsulations
(such as DSS).

Packet
A variable-sized unit of information that can be sent across a packet-switched
network. NTSC.

PAL
Phase Alteration Line. 50 Hz video format used in much of the world outside of the
USA. Not NTSC.

PAR
Peak to Average Ratio. Also, Project Authorization Request. When IEEE starts a new
standards committee.

PCI
Personal Computer Interface. The bus that most personal computers use.

PCM
Pulse Code Modulation. A common lossless encoding of Audio.

PDU
Protocol Data Unit. Usually ISO speak for “packet”.

PE
Protocol Engine. The general purpose programming engines of our defunct switch.

PHY
Physical Layer Device. A PHY can be a fiber optic device or a copper device. It can
operate at any speed… 1Mbps, 10Mbps, 100Mbps, 1000Mbps, etc.

PMMU
Paged Memory Management Unit

PNP
Positive Negative Positive

POF
Plastic Optical Fiber

Point-to-Multipoint
An arrangement, either permanent or temporary, in which the same
data flows or is transferred from a single origin to multiple
destinations.

POP
Point Of Presence

Port
A specific line into a switch, specified by shelf, slot, and port within that slot.

POST
Power On Self Test

POTS
The traditional analog voice telephone service (4 kHz or less audible signals,
rings, off hook signals, etc…).

PPP
Point to Point Protocol. Some standard encapsulations and negotiations for Internet
Protocol point-to-point links.

PPTP
Point to Point Tunnel Protocol

PQFP
Plastic Quad Flat Pack

PR
Public Relations, Press Relations, or Press Releases.

PRM
Preamble. Header on each frame used to train demodulator.

PSD
Power Spectral Density

PSK
Phase Shift Keying. Modulation with constant amplitude.

PSTN
Public Switched Telephone Network

PThread
POSIX Thread. A “standard” multi-tasking OS primitive interface.

PVC
Permanent Virtual Connection. A manually configured virtual circuit through an ATM
network.

QAM
Quadrature Amplitude Modulation. A digital modulation technique that allows very
efficient transmission of data over media with limited available bandwidth.

Quick Turn
The purchase and sale of an investment held for only a very brief period
of time, such as in day trading.

QPSK
Quadrature Phase Shift Keying. A digital technique which is widely employed in
direct broadcast satellite transmission systems.

QSIF
Quarter Standard Interchange Format.

RADIUS
Remote Authentication Dial-In User Service. Authorization protocol,
IETF RFC 2138

RADSL
Rate Adaptive Digital Subscriber Line. Picks the best data rate that the line
can handle.

RDT
Remote Digital Terminal

RED
Random Early Drop. A congestion control algorithm for Internet protocols.

RGB
Red Green Blue. Component video color model used in PC frame buffers, and high
end professional (even digital) systems.

Relite
Integrated analog front end for DNIC.

Repeater
Device that amplifies weak signals without regeneration or processing.

RF
Radio Frequency

RFC
Request For Comments. Traditional name for Internet standards documents (and
Internet informational documents).

RFP
Request for Proposal

RLL25
Run-Length Limit bit encoding used in Tut HomeRun.

RMAN
Resource Manager. Part of the switch software.

RMII
Reduced Media Independent Interface

RMS
Root Mean Square. An “average” of an analog signal.

Router
A device that routes data between networks through IP addressing information
contained in the header of the IP packet.

RPC
Remote Procedure Call

RSVP
Resource Reservation Protocol

RTR
Runtime Reconfigurable (system)

RTS
Run Time Support.

SA
Source Address

SAN
System Area Network. Now, Storage Area Network (disks and tapes).

SAP
Session Announcement Protocol

SBUS
A proprietary input/output (I/O) bus developed by Sun Microsystems

SCLK
Synchronous with Clock

SCRAMBLER
In 1000BASE-T and 100BASE-TX modes, the transmit data stream is scrambled to
reduce radiated emissions and to ensure that there is no correlation between
symbols in the data stream.

SDH Synchronous Digital Hierarchy. CCITT Family of data networking standards for high
rates over fiber-optics.

SDI     Serial Digital Interface, for video uncompressed, e.g. 1.5 Gbps for HDTV.

SDP
Session Description Protocol. Used in IETF protocols to announce multimedia events,
through the session announcement protocol, SAP.

SDSL
Symmetric Digital Subscriber Line. A flavor of xDSL with the same bandwidth in both
directions.

SDTV
Standard Definition Television, 480 lines or less.directions.

Server Farm
A system that allows for scalable, fault-tolerant, and centralized
connectivity for enterprise servers.

Set-top Box
An electronic device that serves as an interface between a television set
and a broadband network.

SHA-1
Secure Hash Algorithm

SIC
System area network Interface Chip

SKU
Stock Keeping Unit

SLB
Smart Load Balancing

SLI
Subscriber Line Interface (telephone)

SLIC
Subscriber Line Integrated Circuit, System Level Integrated Circuit, Subscriber
Line Interface Card.

SMB
Send Message Block. Microsoft file access protocol.

SMII
Serial Media Independent Interface

SMDS
Switched Multimegabit Data Service

SMIL
Synchronized Multimedia Integration Language

SNAP
Sub Net Access Protocol. Header on LLC frames so that the alignment comes out a
little better, with three bytes of zeros, then the Ethernet type identifier for
the network level protocol 0×08 and 0×00.

SNMP
Simple Network Management Protocol. Used to manage IP networks, by defining
standard MIBs.

SNR
Signal to Noise Ratio

SOHO
Small Office, Home Office

SONET
Synchronous Optical NETwork. A common physical layer for ATM using fiber optics.
Also possible to run PPP or other protocols on top of it. American variant of SDH.
Organized into rings that can tolerate one break (e.g. FDDI).

SPI
Serial Plug In, Standard Programming Interface, Spots per Inch.

SRC
Source (e.g. address of a packet).

SRX
Serial Receive Line

STB
Set Top Box (such as for cable TV).

Streaming Media
Multimedia content – such as video, audio, text, or animation that is
displayed by a user as it is received from the Internet, broadcast
network, or local storage.

STX
Serial Transmit

Sub-ISA
Subset of ISA bus used by the iLine10 chip to bridge to some other device
(such as a modem).

Symbol Rate
Replacement term for Baud: a unit of signaling speed, the number of times
a signal on a communications circuit changes.

SVC
Switched Virtual Connection

SWAP
Shared Wireless Access Protocol developed by HomeRF.

T
Thin

T1
A DS1 rate (1.544 Mbps) signal delivered on two twisted pair of copper wires. The
closest European equivalent is called E1, which is 2.048 Mbps. Also a committee of
ANSI that does telecommunications standards.

TAG
Temporal Annotation Generator. Audio/video editor licensed from Digital Renaissance
for NetShow.

TAPI
Telephony Application Programmers’ Interface

TBI
Ten Bit Interface

TCL
Tool Command Language

TCP
Transmission Control Protocol

TDM
Time Division Multiplexing

TDMA
Time Division Multiple Access

Telecine
Converting movies (24 frames per second) to video
(usually 30 frames per second).

TIC
Time Interval Clock. Tut for 116.6667 nsec.

TMN
Telecommunications Management Network

TOEF
Training on Every Frame. A true packet modem using only the frame preamble.

TOS
Type Of Service

TQFP
Thin Quad Flat Pack

Transceiver
NIC MIPS program which performs energy detection and transfers samples
to and from the AFE.

Trunk Card
Card to connect the switch to an Internet Service Provider (ISP).

Twisted Pair
Cable of two 18 to 24 guage solid copper strands twisted around each other.

TQFP
Thin Quad Flat Pack. Package of first iLine10 digital chip.

Tuner
Any device or apparatus used for selecting and controlling the operating
frequency of a circuit or equipment, such as the channel selector in a
television receiver.

UART
Universal Asynchronous Receiver/Transmitter

UAWG
Universal ADSL Working Group

UNC
Uniform Naming Convention

UNI
User to Network Interface. Protocol between an ATM carrier and a customer.

Upstream
Data flowing from a subscriber towards the central office (CO). Some old
Video on Demand terminology calls this “duplex”, as compared to traditional
cable TV witch is simplex (one direction, downstream, only).

USB
Universal Serial Bus. On every PC since 1997, allows peripherals (albeit sometimes
called dongles) to be added without taking a box apart. ~12 Mbps.

UTP
Unshielded Twisted Pair

VCO
Virtual Central Office. The Cisco VCO/4K (Virtual Central Office 4000) is a
programmable switch that provides voice services such as integrated messaging,
operates as a core infrastructure switch for wireline or wireless networks, or
acts as a gateway in mixed circuit- and packet-switched networks.

VSB
Vestigial Side Band. One of the Digital Television modulations.

V.34
Most common modem modulation. 28.8 Kbps rate.

V.90
Standard for 56 Kbps modems, merging k56flex and x2.

V.anything
Implement modem algorithms in software.

V.IP
Residential Ethernet The internal name V.IP is a pun on the V.n series of modem
standards.

VBI
Vertical Blanking Interval

VBR
Variable Bit Rate.

VCC
Virtual Channel Connection. Identifies a virtual circuit in an ATM switch through an
input port, a virtual channel identifier and virtual path identifier.

VCI
Virtual Circuit Identifier. Part of ATM VCC. 16 bits specifying a connection on a
particular path.

Vector OFDM
Vector Orthogonal Frequency Division Multiplexing.

VDSI
Very High Delivered Source Instruction

VDSL
Very High Bit-Rate Digital Subscriber Line. Twisted pair modem technology that
achieves data rates up to 52 Mbps downstream to the network at distances up to
4,000 feet.

VESA
Video Electronics Standards Association. Consumer electronics inter-connection.

VHDL
Verilog Hardware Description Language

VHE
Virtual Home Environment. GSM scheme to allow cellular phones to work when you
leave one provider area and go to another.

VISA
Virtual Instrument Standard Architecture

Viterbi
Algorithm for BCC Forward Error Correction.

VOB
Video OBject. File format for DVD-video.

VOFDM
Breakthrough radio frequency(RF) thechnology developed to establish an open
broadband fixed wireless standard for enabling reliable communicaion where line
of sight connections are not practical.

VPC
Virtual Path Connection

VPE
Video Port Extension

VPI
Video Port Extension or Virtual Path Identifier.

VSB
Vestigial Side Band. Modulation used for broadcast digital telelvision.

VxWorks
An operating system for embedded devices.

WAN
Wide Area Network. A data communications network, such as the Internet, which
links a variety of data devices over a large geographical distance.

Wavelet
Wavelets are mathematical functions that cut up data into different frequency
components, and then study each component with a resolution matched to its
scale.

WFC
Windows Foundation Classes. Microsoft Java package.

WFQ
Weighted Fair Queuing

Whiff
Operating system running on Digital Signal Processors.

WHQL
Windows Hardware Quality Laboratory

Win32
Important API for Windows 3.x, 95, etc.

WinCE
A variant of Microsoft Windows for palm tops and embedded applications.

Wind
The VxWorks kernel.

WinPHY
Coding and decoding in software by WinModem.

Winsock
Microsoft network programming interface.

Wire Center
The other end of the local loop wires from subscribers.

WMI
Windows Management Instrumentation in NT 5 and Windows 98.

WMP
Window Media Player

x2
A modem technology from U.S. Robotics to send 56 Kbps over voice phone lines.

xDSL
Generic representation of the entire family of Digital Subscriber Line technology
spanning data rates from 128 kbps to 52 Mbps depending on the distance between
the central office subscriber.

XML
Extensible Markup Language

xNIC
A “D” Network Interface Card with Xilinx FPGAs, in 4-10 MHz band.

Y
C / Video signal with separate luminance and chrominance signals, which often is used
on S-Video connectors.

YCrCb
A color model for video.

YUV
A color model for video. The popular 4:2:2 encoding means Y (Luminance) is
sampled twice as often as the UV color values.

YUV12
A specific digital video pixel format. A plane of 8 bit Y values per pixel, then
a plane of 8 bits of U values per four pixels, and 8 bits of V per four pixels.
This gives an average of 12 bits of data per pixel.

YUV9
Like YUV12, but with 4:1:1 sampling, one color value for 16 pixels, for 9 bits
per pixel average.