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A
| ADSL |
Asymmetric Digital Subscriber Line. This is an access technology for implementing broadband transmission over a normal telephone connection. ADSL makes it possible to transfer data at up to 8Mbit/s downstream and up to 768 kbit/s upstream. |
| AVC |
See H.264 |
| Analogue |
Analogue data is continuous in time and amplitute, usually stored and transmitted as contious oscilliations. Analogue is the opposite of digital, where data is stored and transmitted as a discrete set of 0's and 1's. |
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B
| Bandwidth |
1. How much data, usually bits, can be carried over a communications link. Bandwidth is usually expressed in kBit/s, mBit/s and gBit/s.
2. The frequency band that is available for the transmission of data. The bandwidth for analogue systems (e.g. telephone or radio) is measured in Hertz and with digital systems in bit/s. The bandwidth indicates the transmission rate of a medium.
"Bandwidth" is also known as the "Data transmission rate". |
| BRI |
Basic Rate Interface.
Two information channels (B channels), each with a capacity of
64 kbit/s, and a signaling channel with a capacity of 16 kbit/s. |
| Bitrate |
Speed at which data is transmitted in telecommunications, e.g. when faxing, with video conferencing or with modem connections. This term can also be spelled "bit-rate" or "bit rate". Furthermore, it can also be known as the "data-rate". |
| Bit/s |
Bit (binary digit) per second. Unit for the rate at which data is transmitted. This term is defined in the ITU-T G.700 standard. The term "bps" is often used in North American litrature. kbit/s(Kilobits per second) is also a popular unit of transfer rate. |
| BootP |
Bootstrap Protocol. An Internet protocol that enables a diskless workstation to discover its own IP address, the IP address of a BOOTP server on the network, and a file to be loaded into memory to boot the machine. This enables the workstation to boot without requiring a hard or floppy disk drive. The protocol is defined by RFC 951. |
| Browser/Web browser |
A computer program which allows transmission of data using the HTTP protocol and hence makes the World Wide Web usable, for example, Microsoft Internet Explorer, Netscape Navigator, Mozilla Firefox. Browsers display web pages, one should be viewing this site through a web browser. |
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| CDMA |
Code Division Multiple Access. This is a technology for the transmission of digital data via radio signals. For example, communication between a mobile phone and a radio base station. |
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| DHCP |
Dynamic Host Configuration Protocol. A protocol for assigning dynamic IP addresses to devices on a network. With dynamic addressing, a device can have a different IP address every time it connects to the network. In some systems, the device's IP address can even change while it is still connected. DHCP also supports a mix of static and dynamic IP addresses.
Dynamic addressing simplifies network administration because the software keeps track of IP addresses rather than requiring an administrator to manage the task. This means that a new computer can be added to a network without the hassle of manually assigning it a unique IP address. Many ISPs use dynamic addressing for dial-up users. |
| DMB |
Digital Media Broadcasting. A transmission system for sending digital data, TV and radio to hand held devices such as mobile phones. It can be operated via terrestrial, T-DMB, or satellite, S-DMB, transmission. |
| DOCSIS |
Data Over Cable Service Interface Specification, is a standard which defines the communications and support interface needs for a data over cable system. |
| Domain |
A group of computers and devices on a network that are administered as a unit with common rules and procedures. Within the Internet, domains are defined by the Internet Protocol(IP) address. All devices sharing a common part of the IP address are said to be in the same domain. |
| DNS |
Domain Name System. An Internet service that translates domain names into IP addresses. For example, a DNS server might translate the domain name www.example.net into 187.132.234.86. |
| DRM |
Digital Rights Management. DRM is any technology used to protect content from being copied in such a way that would result in copyright infringement. |
| DSLAM |
Digital Subscriber Line Access Multiplexer. A technology that concentrates traffic in ADSL implementations through a process of TDM (time division multiplexing) at the CO or remote line shelf. |
| DVB |
Digital Video Broadcasting. A set of internatinally accepted, open standards for the broadcasting of digital television. DVB has a series of sub-standards. DVB is maintained by the DVB project, an industry-led consortium of broadcasters, manufacturers, network operators, software developers and regulatory bodies. More information can be found at http://www.dvb.org. |
| DVB-C |
Digital Video Broadcasting-Cable. A sub-standard of DVB describing the broadcast transmission digital television over cable. |
| DVB-H |
Digital Video Broadcasting-Handheld. A sub-standard of DVB describing the broadcast transmission digital television to handheld devices. |
| DVB-S |
Digital Video Broadcasting-Satellite. A sub-standard of DVB describing the broadcast transmission digital television via satellite. |
| DVB-S2 |
Digital Video Broadcasting-Satellite2. A newer specification of the DVB-S standard which has resulted in performance gain. |
| DVB-T |
Digital Video Broadcasting -Terrestrial. A sub-standard of DVB describing the broadcast transmission digital terrestrial television. |
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| EPG |
Electronic Program Guide. EPG is synonymous with IPG (Interactive Program Guide). It is an on-screen, interactive broadcast TV guide. The user can navigate, select and discover content by time, channel, genre, title and more, simply by using one's remote control, keyboard or mobile phone keypad. |
| EPROM |
Erasable Programmable Read Only Memory. A special type of memory that retains its contents until it is exposed too ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory. To write to and erase an EPROM, one needs a special device called a PROM programmer or PROM burner. |
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| GSM |
Global System for Mobile communications. GSM is the most common standard for mobile phone communications. |
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| H.264 |
H.264 is a standard for high compression digital video developed jointly by the ITU-T Video Coding Experts Group(VCEG) and the ISO/IEC Moving Picture Experts Group(MPEG). H.264 delivers high quality video in less data than other standards.
The H.264 contains six sets of capabilities, referred to as "profiles", each profile tagets a specific class of application. |
| H.264 Baseline Profile | A profile of H.264, it primarily targets lower-cost appilcations demanding less computer resources. The Baseline Profile is used widely in videoconferencing and mobile applications. |
| H.264 Main Profile |
A profile of H.264, it was originally intended to be the mainstream consumer profile for broadcast and storage application. The High Profile wqs then developed for these application and the Main Profile became less important. |
| H.264 Extended Profile |
A profile of H.264, it is intended as a video streaming profile due to it relatively high compression. |
| H.264 High Profile |
A profile of H.264, the primary profile for for broadcast and storage implementations, especially in high-definition television applications. |
| H.263 |
H.263 is an old video encoding standard still supported in video conferencing. |
| H.323 |
A standard which defines protocols used to provide audio-visual communication sessions on any packet network. H.323 is used in Voice Over IP and IP-based videoconferencing. |
| HFC |
Hybrid Fibre-Coaxial cable network. A network that comprises both optical fibre and coaxial cables. The advantage of such a network is reduced losses and the possibility of higher data rates. |
| HTTP |
Hypertext Transfer Protocol. The underlying protocol used by the World Wide Web. HTTP defines how messages are formatted, transmitted and which actions servers and browsers should take in response to various commands. For example, when one enters a URL in a browser, a HTTP command is sent to the Web server directing it to fetch and transmit the requested Web page. |
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| IP Address |
An identifier for a computer or device on a TCP/IP network. Networks that use the TCP/IP protocol route messages according to the IP address of the destination. The format of an IP address is a 32-bit numeric address written as four numbers separate by periods. Each number can be zero to 255. For example 192.168.10.243 can be an IP address. |
| IP Multicast |
Sending out data to distributed servers on the MBone. (Multicast Backbone) For large amounts of data, IP Multicast is more efficient than normal Internet transmissions because the server can broadcast a message to many recipients simultaneously. Unlike traditional Internet traffic that requires separate connections for each source-destination pair , IP multicasting allows many recipients to share the same source. This means that just one set of packets is transmitted for all destinations. |
| IPG |
Interactive Program Guide. See EPG. |
| IPTV |
Internet Protocol Television. A system whereby television content is delivered to the viewer via technologies used for computer networks, rather than through traditional formats and cabling. |
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| JDBC |
Java Database Connectivity. A Java API that enables Java programs to execute SQL statements. This allows Java programs to interact with any SQL-compliant database. JDBC makes it possible to write a single database application that can run on different platforms and interact with different database management systems as nearly all relational database management systems support SQL and Java runs on most platforms. |
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| Korn shell |
A unix shell developed by by David Korn of AT&T which contains enhanced features. |
| kBit/s |
Also known as kB/s, see Bit/s. |
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| Listening Post |
A socket on the set-top box that handles update messages from the server. |
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| Macrovision |
An anti-taping process that protects original material from video piracy. For example, a viewer cannot record a pay-per-view movie if macrovision protection is in place. |
| MAC Address |
Media Access Control address, a hardware address uniquely identifies each node of a network. In IEEE 802 networks, the Data Link Control(DLC) layer of the OSI Reference Model is divided into two sublayers: the Logical Link Control(LLC) layer and the Media Access Control(MAC) layer. The MAC layer interfaces directly with the network media. Consequently, each different type of network media requires a different MAC layer. |
| MATV |
Master Antenna TV. Where one antenna supplies many televisions. Such a system may be used in hotels, offices, apartment buildings, retirement villages and other large residential developments. See also SMATV. |
| MGCP |
Main Gateway Control Protocol. An internal protocol used within a Voice Over IP system. |
| MHP | Multimedia Home Platform.(DVB-MHP) A middleware system standard developed by the DVB project for interactive digital television. The MHP enables a user to recieve and execute interactive, Java-based application on a TV-set. These application can be delivered over the broadcast channel, together with the audio and video streams. MHP appilcations can very diverse such as games, information services, interactive voting, e-mail, sms or shopping. |
| Middleware | A set of software agents acting a intermediary between different components of an application. |
| MP3 | MPEG-1 Audio Layer 3. A popular digital audio encoding format. It is desinged greatly reduce the amount data required to represent audio, yet still sound like an exact reprodruction of the original uncompressed sound. MP3 is a lossy compression format. |
| MPEG |
Motion Picture Experts Group. This is an industry organization, the purpose of which is to develop specifications and standards for the encoding, compression, transmission, decompression and unencoding of video data over various media and network technologies. However, the term MPEG often refers to the format itself. |
| MPEG-1 |
This is a compression scheme for full motion video. Implementations of the MPEG-1 standard provide a video resolution of 352x240 at 30 frames per second(fps). |
| MPEG-2 |
MPEG-2 is the standard used in DVD players and many digital TV systems. Implementations of this standard offer resolutions of 720x480 and 1280x720 at 60 frames per second(fps), there separate specifications for audio and video. |
| MPEG-4 |
MPEG-4 Visual can support bit rates between 5Kps more than 1Gbps. Video formats can be progressive scan as well as interlaced video, with resolutions range up to approximately 4000x4000 pixels. MPEG-4 also supports a wide variety of elements that can be transmitted separately and combined to form the video frame, background and foreground objects for example. MPEG-4 is made up of several standards, they are called "parts". |
| MPEG-4 Part10 |
See H.264 |
| MPEG-7 |
In October 1996, the Motion Picture Experts Group started a new work item in order to provide a new solution to the urging problem of generally recognised descriptions for audio-visual content, which extend the capabilities of proprietor solutions in identifying content that still exist today. This new member of the MPEG family is called "Multimedia Content Description Interface", abbreviated to MPEG-7. |
| Multicast |
Multicast is communication between a single send and multiple receivers on a network. Multicast is the specialty of the MBone system, which allows users to receive live video and sound programming. |
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| Network Mask |
A filter the selectively includes or excludes certain values. For example, when defining a database field, it is possible to assign a mask that indicates what sort of value the field should hold. You cannot enter values that do not conform to the mask. |
| NAT |
Network Address Translation. An internet standard that enables a local-area network(LAN) to use on set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet, makes all necessary IP address translations. NAT servers three main purposes:
- Provides a type of firewall by hiding internal IP addresses.
- Enables a company to use more internal IP addresses. Since they are used internally only, there is no possibility of conflict with IP addresses used by other companies and organizations.
- Allows a company to combine multiple ISDN connections into a single Internet connection.
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| NFS |
Network File System. An open architecture operating system designed by Sun Microsystems that allows all network users to access shared files stored on computers of different types. NFS provides access to shared files through an interface called the Virtual File System(VFS) that runs on top of TCP/IP. Users can manipulate shared files as if they were stored locally on the user's own hard disk.
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| NPVR |
Network Personal Video Recorder. Performs the same function as a PVR, except the recorded program is stored on the network instead of the user’s hard drive. See PVR.
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| Portal Page |
A portal page is a special type of web page that contains links to other web pages, search engines and help facilities. |
| Push VOD |
Push Video On Demand. Push VOD is when content batches, often being batches of movies, are “pushed” from a server, located within the ISP's infrastructure, to home users Set-Top-Boxes (STB) hard drives at operator-scheduled times. This usually occurs at time of low network traffic. The amount of content pushed, the movie selection, is limited by STB’s hard drive. Home users may watch movies after the recording process on their STB after the transfer has been completed and take advantage of DVD-like functions (rewind, fast-forward, pause, etc). See VOD.
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| PVR |
Personal Video Recorder. A device or software that allows a user to record television programs in real time. The user can watch, pause, rewind and fast forward the program while it is being received and recorded. The recorded program is usually stored on a hard drive on the user’s computer or set top box. See also NPVR.
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| RC5 |
An encryption/decryption algorithm supported in Cellular Digital Packet Data(CDPD). |
| RPC |
Remote Procedure Call. A type of protocol that allows a program on one computer to execute a program on a server computer. Using RPC, a system developer need not develop specific procedures for the server. The client program sends a message to the server with appropriate arguments and the server returns a message containing the results of the program executed. |
| RTP |
Real-time Transport Protocol. This protocol defines a standardized packet format for delivering video and audio over the internet. |
| RTSP |
Real Time Streaming Protocol. A protocol used in streaming media systems. It enables the client to remotely control a streaming media server with VCR-like commands such as "play" and "pause" and allows time-based access to file on the server. |
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| S-DMB |
Satellite-Digital Media Broadcasting. A transmission system for sending digital data, TV and radio to hand held devices such as mobile phones via satellite transmission. |
| SCCP |
Skinny Client Control Protocol.A terminal control protocol used as a messaging set between a skinny client and the CISCO Call Manager. |
| Servlet |
An applet that runs on the server. The term usually refers to a Java applet that runs within a web server environment. Java servlets are becoming increasingly popular as an alternative to CGI programs. The biggest difference between the two is that a Java applet is persistent. This means that once it is started, it stays in memory and can fulfill multiple requests. In contrast, a CGI program disappears once it has fulfilled a request. The persistence of Java applets make them faster than CGI because there's no wasted time in setting up and shutting down the process. |
| Set Top Box | The Set Top Box(STB) is a device which connects to the user's television and some external source of signal. The Set Top Box decodes the signal from the external source into content and sends it to the user's television which displays the content. |
| SIP |
Session Initiation Protocol. A signaling protocol and proposed standard for the initiation, modification and termination of interactive user sessions involving multimedia elements such as video, voice, instant messaging, online games and virtual reality. SIP is the leading signaling protocol for Voice Over IP. |
| SMATV |
Satellite Master Antenna TV. Where one satellite antenna system supplies many televisions; the received signal may come from a satellite or terrestrial source. Such a system may be used in hotels, offices, apartment buildings, retirement villages and other large residential developments. See also MATV. |
| STB |
See Set Top Box. |
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T
| T-DMB |
Terrestrial-Digital Media Broadcasting. A transmission system for sending digital data, TV and radio to hand held devices such as mobile phones via terrestrial transmission. |
| TCP/IP |
Transmission Control Protocol/Internet Protocol. The suite of communications protocols used to connect hosts on the internet. TCP/IP uses several protocols, the two main ones being TCP and IP. TCP/IP is built into the UNIX operating system and is used by the internet; it is a very common standard for transmitting data over networks. |
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| UDP |
User data Protocol. A connectionless protocol that, like TCP, runs on top of IP networks. Unlike TCP/IP, UDP/IP provides very few error recovery services. However, it offers a direct way to send and receive datagrams over an IP network. It is used primarily for broadcasting messages over a network. |
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| Video On Demand |
With Video On Demand, a user is able to watch video content over a network as part of an intereactive television system. The content is either streamed, downloaded while playing, or downloaded entirely before playing. Abbreviated to VOD. |
| VOD |
See Video On Demand. |
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| WCDMA |
Wideband CDMA. This is a technology for the transmission of digital data via radio signals used for 3G mobile phone services. |
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| XML |
Extensible Markup Language. XML is a way of describing data, an XML file can contain data as well; similar to a database. It is primarily used to facilitate the sharing of data across different systems, especially ones connect to the internet. |
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