0G - PTT, MTS, IMTS, AMTS are 0G standards.

0.5G - Autotel/PALM and ARP are 0.5G standards.

1G - First Generation. The first generation of cellular wireless (1G) was based on analog technology. The systems were designed only to carry voice technology. NMT, AMPS, Hicap, CDPD, Mobitex, DataTac are 1G standards.

2G - Second Generation.  Second-generation (2G) technology converts voice to digital data for transmission over the air and then back to voice. Most 2G systems provide 9.6–14.4-Kbps circuit-switched data service.  Examples would be GSM, iDEN, D-AMPS, CDMAOne, PDC, CSD, and PHS.

2.5G - 2.5G refers to technology that is added to a 2G network to provide packet-data service. In practice, 2.5G is synonymous with the GPRS technology that has been added to GSM networks. HSCSD, and WiDEN are other examples of 2.5G

2.75G - CDMA20001xRTT and EGPRS or EDGE (a further evolution of GPRS)

3G - Third Generation. Third-generation (3G) systems have been designed for both voice and data. By International Telecommunications Union (ITU) definition, 3G systems must provide a minimum of 144-Kbps packet-data service.  3G examples are: W-CDMA UMTS FOMA, CDM2000 1xEV, TD-SCDMA, and UMA standards.

3.5G - HSDPA is a 3.5G standard.

3.75G - HSUPA is a 3.75G standard.

3GPP - The 3rd Generation Partnership Project is a collaboration agreement that was established in December 1998. It's a co-operation between ETSI (Europe), ARIB/TTC (Japan), CCSA (China), ATIS (North America) and TTA (South Korea).  The scope of 3GPP is to make a globally applicable third generation (3G) mobile phone system specification within the scope of the ITU's IMT-2000 project. 3GPP specifications are based on evolved GSM specifications, now generally known as the UMTS system.  Note that 3GPP should not be confused with 3GPP2, which specifies standards for another 3G technology based on IS-95 (CDMA), commonly known as CDMA2000.  3GPP standards are structured as Releases. Discussion of 3GPP thus frequently refers to the functionality in one release or another: Release 98 and earlier releases specify pre-3G GSM networks. Release 99 specify the first UMTS 3G networks, incorporating a CDMA air interface. Release 4 - originally Release 2000 - adds features including an All IP Core Network Release 5 introduces IMS and HSDPA.  Release 6 integrates operation with Wireless LAN networks and adds HSUPA.  Release 7 work towards better integration with wired networks.  Release 8 GSM Phase 2+ and UMTS Release 8, Handover capabilities for combinational services between WCDMA and WLAN networks.

75-Ohm Antenna/Cable Input - Compatible with any 75-ohm set-top/roof-top VHF/UHF antenna system as well as any residential/commercial CATV/CCTV system.

Acoustic Echo Canceller (AEC) - Full Duplex audio technology; used for the elimination of acoustically-coupled return echoes within a teleconference room. Note that all microphones connected to an AEC are active at all times. Consequently, as more microphones are added, the total transmitted noise level (caused by picking up room ambient noise) increases.

Access Method - In Local Area Networks, the technique and /or program code used to arbitrate the use of the communications medium by granting access selectively to individual stations.  Examples are CSMA/CD and Token Passing.

Access Point (AP) - A networking device that enables wireless stations to access the wired LAN infrastructure.

Adaptor - computer add-in board.  Network adapters are used to connect end user nodes to the network; each contains an interface to a specific type of workstation or system bus.  E.g.:  EISA, ISA, MCA, VME, etc.

 Adaptive Routing - A form of routing in which messages are forwarded through the network along the most cost-effective path currently available and are automatically rerouted if required by changes in the network topology (for example, if a circuit becomes disabled.)

Address - A designator defining the unique ID of a terminal, peripheral device or any other nodal component in a network.

ADM - Add-drop multiplexer - A main element of optical fiber networks. An add-drop multiplexer combines, or multiplexes, several lower-speed streams of data into a single beam of light. ADMs can be used both in long-haul core-networks and in shorter distance metro networks, although in recent years (2002-04) most ADM sales have been in metro networks due to the high cost required to scale the technology to high data rates (wavelength division multiplexing, better known as DWDM, is more popular in the core).

Ad-hoc Network - An ad-hoc network is a wireless network created for a specific purpose, typically in a spontaneous manner without use of an access point.  The principle characteristic of an ad-hoc network is that the act of creating and dissolving the network is sufficiently straightforward and convenient so as to be achievable by non-technical users of the network facilities.

ADSL - Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide.  ADSL uses two separate frequency bands. The band from 25.875 kHz to 138 kHz is used for upstream communication, while 138 kHz - 1104 kHz is used for downstream communication.

The ADSL Standards are as follows:

Adware - Adware or advertising-supported software is any software package which automatically plays, displays, or downloads advertising material to a computer after the software is installed on it or while the application is being used.

AES - Advanced Encryption Standard (AES), also known as Rijndael, is a block cipher adopted as an encryption standard by the US government, and is expected to be used worldwide and analyzed extensively, as was the case with its predecessor, the Data Encryption Standard (DES). It was adopted by National Institute of Standards and Technology (NIST) as US FIPS PUB 197 in November 2001 after a 5-year standardization process (see Advanced Encryption Standard process for more details).  The cipher was developed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen, and submitted to the AES selection process under the name "Rijndael", a portmanteau comprised of the names of the inventors. Rijndael can be pronounced "Rhine dahl", a long "i" and a silent "e".

Alias, Aliasing - A false signal produced by the analog-to-digital sampling process. Often caused by failure to observe the Nyquist criterion and can create artifacts which are subjectively. A common form of aliasing is a stair-stepped appearance along diagonal and curved lines.

Algorithm - The specific formula or procedure used to compress and decompress digital audio and video.

American National Standards Institute (ANSI) -  An organization that coordinates, develops, and publishes standards Standards Institute for use in the United States.  It also represents the United States in  the International Standards Organization (ISO).

AMPS Analog - Advanced Mobile Phone Service (AMPS) has been available since 1976 when it was first used on a trial basis in the U.S. and then commercialized in the early 1980s. With AMPS, each channel can handle a single voice call. In order to add more capacity to an AMPS cellular system, more channels per cell site or more cell sites must be added.

AMR - Adaptive Multi-Rate is an Audio data compression scheme optimized for speech coding. AMR is adopted as the standard speech codec by 3GPP. The codec has eight bit rates, 12.2, 10.2, 7.95, 7.40, 6.70, 5.90, 5.15 and 4.75 Kbit/s. The bitstream is based on frames which contain 160 samples and are 20 milliseconds long. AMR uses different techniques, such as Algebraic Code Excited Linear Prediction (ACELP), Discontinuous Transmission (DTX), voice activity detection (VAD) and comfort noise generation (CNG). The idea to use various modes arises from the network conditions. If the channel is bad, source coding is reduced and channel coding is increased. This improves the quality and robustness of the network. In the particular case of AMR this improvement is somewhere around 4-6 dB S/N for useable communication. The usage of AMR requires optimized link adaptation that selects the best codec mode to meet the local radio channel and capacity requirements. The new intelligent system allows the network operator to prioritize capacity or quality per base station.

Analog video - A video signal represented in a waveform by physical variables such as voltage and current.

ANSI-136 - is called TDMA in the Americas. See TDMA Standards, D-AMPS.

ANSI-41 - ANSI-41 is a protocol standardized by the Telecommunications Industry Association (TIA) and the American National Standards Institute (ANSI) for enabling cdmaOne, cdma2000 and TDMA subscribers to roam between different wireless service operators’ systems to make and receive voice calls.

ANSI X3T9.5 - A sub-committee sponsored by ANSI, which sets system interconnection standards, including the specifications for Fiber Distributed  Data Interface (FDDI).

Antialiasing - A method for smoothing the jagged edges (stair steps) often seen in graphics or video. The method reduces the jagged edges by placing intermediate shades of color or gray around the steps.

AS - An Application Server is a server computer in a computer network dedicated to running certain software applications. The term also refers to the software installed on such a computer to facilitate the serving (running) of other applications.  Following the success of the Java platform, the term application server often refers to a J2EE application server. WebSphere (IBM), Oracle Corporation (Application Server 10g) and WebLogic (BEA) are the better known commercial J2EE application servers. The JOnAS application server, developed by the ObjectWeb consortium, is the first non-commercial, open source application server to have reached the official certification of compliance with J2EE. The programming language used is Java. The web modules are servlets and JavaServer Pages (JSP), and business logic is built into Enterprise JavaBeans (EJB). The Java 2 Platform, Enterprise Edition (J2EE) provides standards for containing the web components. Tomcat from Apache and JOnAS from ObjectWeb are typical of containers to put these modules into. Both organizations provide the code freely and openly (open source).  JSP is a Servlet from Java that execute in a web container--the Java equivalent of CGI scripts. JSP is a way to create HTML pages by embedding references to the server logic within the page. HTML coders and Java programmers can work side by side by referencing each other's code within their own. JavaBeans are the independent class components of the Java2 architecture from Sun Microsystems. 

The term application server has also been applied to various non-J2EE and non-Java offerings. For example, with the rising popularity of .NET, Microsoft can claim to deliver an application server. Additional open source and commercial application servers are available from other vendors. Some examples are the Base4 Server and Zope. Contrary to prior versions of this entry, Microsoft's Windows Communication Foundation is not an application server, but rather a framework for communication (middleware). 

Artifact - Spurious effects or imperfections introduced into a signal as a result of digital signal processing.  An unintended, unwanted visual abbreviation in a video image.

Aspect ratio - The ratio of the width of an image to its height.  For television, this is typically 4:3.

ASF - Active Streaming Format. A Microsoft file format for digital video playback over the Internet, or on a standalone computer. Kind of a wrapper around any of a number of compression types, including MPEG. Part of Netshow, a proprietary streaming media solution from Microsoft. Biggest competitor is Real Networks. While this 'wrapper' support many standard formats, ASF files are themselves proprietary.

ASIC - Pronounced ay-sik, and short for Application-Specific Integrated Circuit, a chip designed for a particular application (as opposed to the integrated circuits that control functions such as RAM in a PC). ASICs are built by connecting existing circuit building blocks in new ways. Since the building blocks already exist in a library, it is much easier to produce a new ASIC than to design a new chip from scratch.  ASICs are commonly used in automotive computers to control the functions of the vehicle and in PDAs.

ATM - Asynchronous Transfer Mode.  Very high speed transmission technology.  ATM is a high bandwidth, low-delay, connection oriented, cell (or fixed size packet) switching and multiplexing technique.  When purchasing ATM service, you generally have a choice of four different types of service: constant bit rate (CBR): specifies a fixed bit rate so that data is sent in a steady stream. This is analogous to a leased line. variable bit rate (VBR): provides a specified throughput capacity but data is not sent evenly. This is a popular choice for voice and videoconferencing data. available bit rate (ABR): provides a guaranteed minimum capacity but allows data to be bursted at higher capacities when the network is free. unspecified bit rate (UBR): does not guarantee any throughput levels. This is used for applications, such as file transfer, that can tolerate delays.

ATM Adaptation Layer (AAL) - AAL1, AAL2, AAL3/4, and AAL5 are the different types of the ATM adaptation Layer.

ATSC - Advanced Television Systems Committee.  Formed by the Joint Committee on Inter-Society Coordination (JCIC) to establish voluntary standards for Advanced TV (ATV) systems.  The ATSC focuses on digital television, interactive systems and broadband multimedia communications standards.  Membership is open to North and South American including the Caribbean entities.  The main ATSC standards for DTV are 8-VSB, which is used in the transmission of video data, MPEG-2 for video signal compression, and Dolby Digital for audio coding.

AUC - The Authentication Centre or AUC is a function to authenticate each SIM card that attempts to connect to the GSM core network (typically when the phone is powered on). Once the authentication is successful, the HLR is allowed to manage the SIM and services described above. An encryption key is also generated that is subsequently used to encrypt all wireless communications (voice, SMS, etc.) between the mobile phone and the GSM core network. If the authentication fails, then no services are possible from that particular combination of SIM card and mobile phone operator attempted. There is an additional form of identification check performed on the serial number of the mobile phone described in the EIR section below, but this is not relevant to the AUC processing. Proper implementation of security in and around the AUC is a key part of an operator's strategy to avoid SIM cloning. The AUC does not engage directly in the authentication process, but instead generates data known as triplets for the MSC to use during the procedure. The security of the process depends upon a shared secret between the AUC and the SIM called the Ki. The Ki is securely burned into the SIM during manufacture and is also securely replicated onto the AUC. This Ki is never transmitted between the AUC and SIM, but is combined with the IMSI to produce a challenge/response for identification purposes and an encryption key called Kc for use in over the air communications.

Audio 1 & 2 Inputs - Regular phono jacks designed to accompany the S-Video and composite video inputs (respectively); these inputs accept a wide variety of audio sources.

Audio Buffer - A buffer in the target system decoder for storage of compressed audio data.  Typically used to hold audio data for synchronization with its corresponding incoming video data.

Audio Decoder - That part of a decoder responsible for decompressing the audio bit stream as specified by Part 3 of the MPEG standard.

Audio Encoder - That part of an encoder responsible for compressing the audio bit stream as specified by Part 3 of the MPEG standard.

Audio Input with Loop-Through Output - Regular phono jacks designed to accompany the SVGA/VGA, S-Video, and composite video inputs. These inputs accept a wide variety of audio sources.

Audio Masking - A compression technique that drops out one audio signal that cannot be perceived by the human ear because of the presence of another audio signal.

Audio/Video Input Jacks - For fast and easy hookup of peripheral devices such as VCRs, and laser disc players.

Audio/Video Muting - Automatically detects the loss of RF signal. When this happens, video defaults to a blue or black background and audio mutes. The units automatically return to their original settings when the signal is resumed.

Audio only conference add-ins - The ability to add another site into a video conference via an audio connection only. This feature uses a regular phone line connected to the codec to conference in someone who is not near a video site but needs to be part of the conversation.

Audio Stream - A bit sequence of compressed digital audio.

Audio Teleconferencing - Two-way electronic voice communication between two or more people at two or more locations.

Auto Power On - Forces the default power setting to the ON position, preventing sets from being turned off while in use. Additionally, this feature allows all sets to be controlled from a single circuit breaker and forces the set to turn back on automatically after a power interruption.

Automatic Mode Detection - This feature allows the television to detect different video modes, learn screen geometry, and automatically recall screen settings (this feature along with the ability to adjust horizontal and vertical scaling, makes your TV display compatible with most computer software platforms.

Autonomous System - In the Internet, an autonomous system (AS) is a collection of IP networks and routers under the control of one entity (or sometimes more) that presents a common routing policy to the Internet. See RFC 1930 for additional detail on this updated definition. Originally, the definition required control by a single entity, typically an Internet service provider or a very large organization with independent connections to multiple networks, that adhere to a single and clearly defined routing policy. See RFC 1771, the original definition (now obsolete) of the Border Gateway Protocol. The newer definition of RFC 1930 came into use because multiple organizations can run BGP using private AS numbers to an ISP that connects all those organizations to the Internet. Even though there are multiple autonomous systems supported by the ISP, the Internet only sees the routing policy of the ISP. That ISP must have a public, registered ASN. A unique AS number (or ASN) is allocated to each AS for use in BGP routing. With BGP, AS numbers are important because the ASN uniquely identifies each network on the internet.

A/V - Audio/Video.

AVI - Audio Video Interleaved. A Microsoft format for digital audio and video playback from Windows 3.1 Somewhat cross-platform, but mostly a Windows format. Has been replaced by the ASF format, but still used by some multimedia developers.  

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B2BUA - A Back-to-back User Agent is primarily used to interface an IP Multimedia Subsystem (IMS) network to other networks. The B2BUA acts as a proxy to both ends of a SIP call. The B2BUA is responsible for handling all SIP signaling between both ends of the call, from call establishment to termination. Each call is tracked from beginning to end, allowing the operators of the B2BUA to offer value-added features to the call. To SIP clients, the B2BUA acts as a User Agent server on one side and as a User Agent client on the other (back-to-back) side. The basic implementation of a B2BUA is defined in RFC 3261. The B2BUA provides the following functionality:

Banding - The presence of extraneous lines.

Bandwidth - A measure of the amount of data that can fit on a communication channel. In analog communications bandwidth is the width, typically measured in Hertz (or cycles per seconds), of a frequency band f₂ − f₁.  In digital communications, bandwidth is typically measured in bits per second.  The higher the bandwidth, the sharper the picture; low bandwidth can cause a fuzzy picture.  The following is a list of devices bandwidth:

Bandwidth On Demand - using telecommunications equipment to "dial-up" the bandwidth you need.  In circuit switched networks, the use of Inverse Multiplexers (or IMUX) to combine 2 or more fixed bit rate channels (56/64Kbps channels) is an example of bandwidth on demand.  Bandwidth on demand is typically done with digital circuits (digital circuits are easier to combine).  In packet or cell switched networks (e.g. ATM), the same concept applies, but the method of achieving bandwidth on demand is different.

BCP - The Bridge Control Protocol is a support feature described in RFC 3518. The Cisco implementation of BCP is a VLAN infrastructure that does not require the use of sub-interfaces to group Ethernet 802.1Q trunks and the corresponding PPP links. This approach enables users to process VLAN encapsulated packets without having to configure sub-interfaces for every possible VLAN configuration.

BGAN - Broadband Global Area Network is a future Inmarsat network comprising satellites and land earth stations; permits data speeds up to 432 kbps.

BGP - The Border Gateway Protocol is the core routing protocol of the Internet. It works by maintaining a table of IP networks or 'prefixes' which designate network reachability between autonomous systems (AS). It is described as a path vector protocol. BGP does not use technical metrics, but makes routing decisions based on network policies or rules. BGP version 4, is specified in RFC 4271 (as per Jan 2006). This RFC obsoletes RFC 1771. 

BGP supports classless inter-domain routing and uses route aggregation to decrease the size of routing tables. Since 1994, version four of the protocol has been in use on the Internet; all previous versions are considered obsolete.

BGP was created to replace the Exterior Gateway Protocol (EGP) routing protocol to allow fully decentralized routing in order to allow the removal of the NSFNET Internet backbone network. This allowed the Internet to become a truly decentralized system. Very large private IP networks can also make use of BGP; an example would be the joining of a number of large Open Shortest Path First (OSPF) networks where OSPF by itself would not scale to size. Another reason to use BGP would be multi-homing a network for better redundancy. Most Internet users do not use BGP directly. However, since most Internet service providers must use BGP to establish routing between one another, it is one of the most important protocols of the Internet.

Compare and contrast this with Signaling System 7, which is the inter-provider core call setup protocol on the PSTN.  A BGP peer uses a simple Finite State Machine (FSM) to make decisions in its operations with other BGP peers. The FSM consists of six states: Idle, Connect, Active, OpenSent, OpenConfirm, and Established. A BGP peer will transition the TCP connection to another peer between these states as it attempts to establish and maintain a session with that peer.  BGP uses the following criteria to determine the path to use (from top to bottom): 1-) An explicit route (i.e. not a default route) for the next-hop router must exist in the routing table.  2-) Prefer the path with the highest weight (Only on Cisco routers).  3-) Prefer the path with the highest local preference.  4-) Prefer any BGP originated on this router.  5-) Prefer the route with the shortest AS path.  6-) prefer the route with the lowest origin (IGP < EGP < ?).  7-) Prefer the path with the lowest MED (Multi exit discriminator).  8-) Prefer external paths to internal paths.  9-) Prefer the path with the lowest IGP metric to the next hop.  10-) If all remaining p