A condition that occurs when a packet's transmission frequency (data rate) does not match the local transmit frequency.
See Data File and Database Management System.
See Data Monitor.
A device used in digital transmission systems to convert an input digital signal into a pseudo random sequence free from long runs of marks, spaces, or other simple repetitive patterns.
A single tip and ring line off the PBX which is protected against any tones (like call waiting) or break-ins that would otherwise mess up any ongoing data transmission call.
The protection of data from unauthorized (accidental or intentional) modification, destruction, disclosure, or delay.
A pre-defined set of data elements ordered sequentially within a set, beginning and ending with unique segment identifies and terminators. Data segments combine to form a message. Their relation to the message is specified by a Data Segment Requirement Designator and a Data Segment Sequence. Data Segment is an EDI (Electronic Data Interchange) term .
An EDI (Electronic Data Interchange) requirement designator determines that if and when the data segment will occur in a message:
MANDATORY. The segment must appear in the message.
CONDITIONAL. The segment will occur in the message depending on agreement conditions. The relevant conditions must be given as part of the message definition.
OPTIONAL. The segment may or may not occur.
In Electronic Data Interchanges, each data segment has a specific place within a message. The data segment sequence determines exactly where a segment will occur in a message:
HEADING AREA. A segment occurring in this area refers to the entire message.
DETAIL AREA. A segment occurring here is detail information only will override any similar specification in the header area.
SUMMARY AREA. Only segments containing total or control information may occur in this area (e.g., invoice total, etc.)
DSU. Device designed to connect a DTE (Data Terminal Equipment like a PC or a LAN) to a digital phone line to allow fully-digital communications. A DSU is sort of the digital equivalent of a modem. In more technical terms, a DSU is a type of short haul, synchronous data line driver, normally installed at a user location that connects a user 's synchronous equipment over a 4-wire circuit to a serving dial-central- office. This service can be for a point-to-point or multipoint operation in a digital data network. DSUs are typically used for leased lines. For switched digital services, you need a CSU/DSU (also called a DSU/CSU). See CSU/DSU and DSU/CSU.
In AT&T jargon, a data set is a modem, i.e. a device which performs the modulation/demodulation and control functions necessary to provide compatibility between business machines which work in digital ( on-off ) signals and voice telephone lines. In IBM jargon however, a data set is a collection of data, usually in a file on a disk. See also Modem.
One of the control signals on a standard RS-232-C connector. It indicates whether the data communications equipment is connected and ready to start handshaking control signals so that transmission can start. See RS-232-C and the Appendix.
The total of the number of bits per second in the transmission path of a data transmission system. A measurement of how quickly data is transmitted, expressed in bps, bits-per-second.
Part of a terminal in which data is received from a data link.
A circuit interface to a radio scanner which provides a means of determining the performance of a radio system (e.g., microwave) using FSK (Frequency Shift Keying) for purposes of digital transmission. FSK shifts frequencies at specific points in time in order to represent ones and zeros. The data slicer allows a technician or engineer to determine whether the radio system is working properly. It does this by logically "slicing" the radio waves in time in order to view the ones and zeros of the data stream.
The originating device in a data communications link.
An object identifier in RMON that represents a particular interface.
Any digital service, T-1, 56K, ISDN or data carrying service.
A new role of data caretaker emerging in business units. Individual takes responsibilities for the data content and quality.
Collection of characters and data bits transmitted through a channel.
An SCSA term. A continuous flow of call processing data.
A person who makes a living doing online research and information retrieval. Also known as a Cybrarian (comes from cyberspace librarian) or a super searcher. See Cybrarian.
DSE. The equipment installed at a single location to perform switching functions such as circuit switching, message switching, and packet switching.
The process of keeping database data timely and relevant by sending and receiving information between laptops, between desktops in the field and between bigger computers at headquarters. See also Synchronization and Replication.
A generic term for a piece of equipment in a system capable of sending and/or receiving data signals.
DTE. A terminal device in the data world. DTE is part of a broader grouping of equipment known as CPE (Customer Premises Equipment), which includes voice, as well as data, terminals. At the terminal end of a data transmission, DTE comprises the transmit and receive equipment. DTE can be in the form of a dumb terminal (i.e., a terminal without embedded intelligence in the form of programmed logic), a semi-intelligent terminal, or an intelligent host computer (i.e., a PC, mid-range or mainframe computer). DTE interfaces to a circuit through DCE (Data Communications Equipment). See DCE and DTE.
One of the control signals on a standard RS-232-C connector. It indicates if the data terminal equipment is present, connected and ready and has had handshaking signals verified . See RS-232-C and the Appendix.
The speed at which data is transferred from one device to another. Data transfer rates are typically expressed in megabits (a million bits) or megabytes (a million bytes) per second.
A call control signal transmitted by a DCE to a DTE to indicate that a distant DTE wants to exchange data.
The time that elapses between the initial offering of a unit of user data to a network by transmitting data terminal equipment and the complete delivery of that unit to receiving data terminal equipment.
When converting a database from one format to another, several conversion programs will convert the data to a common format before converting it to the final version. During the conversion process a program may check through the data in the database to determine what it is and arbitrarily make one field numeric, one field character, one field memo, etc.
DUP. Higher layer application protocol in SS7 for the exchange of circuit switched data; not supported by ISDNs.
A data warehouse is a central repository for all or significant parts of the data that an enterprise's various business systems collect. This data can either be accessed quickly by users or put on an OLAP server for more thorough analysis. Data warehouses often use OLAP servers. OLAP stands for On Line Analytical Processing, also called a multidimensional database. According to PC Week, these databases can slice and dice reams of data to produce meaningful results that go far beyond what can be produced using the traditional two-dimensional query and report tools that work with most relational databases. OLAP data servers are best suited to work with data warehouses. See Data Warehousing.
Imaging Magazine (now called Transform Magazine) once wrote a story on data warehouses. The writer, Joni Blecher, found "defining a data warehouse to be puzzling at best." She said these definitions seem to make the most sense:
A collection of physical data stores designed to concisely present a historical perspective of the events that occur in an enterprise. Data warehousing is a set of activities some of which are optional and some mandatory that create, operate and evolve the collection of data stores that make up the data warehouse. ” Actium.
An extremely comprehensive solution that includes hardware, software, middleware, partner products as well as their own professional services focused on solving business problems through the enterprise level. ” NCR.
The place where business managers can access information for managerial processes. They're built for decision making purposes. It's an elaborate process that consists of a solution made up of many products. ” Oracle.
A group of individuals, processes, methodologies ” all the things that deal with and manage data including cleansing, enhancing, standardizing, consolidating and disseminating it. ” Acxiom.
A data store that companies build where they're storing their information assets so they can extract knowledge and understanding to the operation and performance of their business. ” Logic Works.
The term was coined by W. H. Inmon. IBM sometimes uses the term "information warehouse."
A software strategy in which data is extracted from large transactional databases and other sources and stored in smaller databases, making analysis of the data somewhat easier. See Data Warehouse.
The term is typically used in relation to information services that are made available by digital TV, such as complimentary information presented in addition to TV programming. A datacasting service is broadly defined as a service that delivers content in the form of text, data, speech, music or other sounds or visual images (or in any form or combination of forms) to persons with appropriate reception equipment, when the delivery of the service uses the broadcasting service bands.
In October, 2003, the Walt ith a new movie rental service called Moviebeam, Walt Disney Co. is betting that consumers' intense dislike for paying video-rental late fees will trump their resistance to attaching yet another electronic device to their TV sets.
Disney Monday began rolling out Moviebeam, a low-cost effort to deliver movies from most of the Hollywood studios directly into homes , where they can be watched on demand. The service ” which is being launched initially in Salt Lake City; Spokane, Wash; and Jacksonville, Fla. ” works like this: Consumers pay a monthly fee of $6.99 to use a device containing a 160-gigabyte hard drive that holds 100 movies, which is plugged into the back of a TV set. A charge also is assessed for each movie that is watched. A phone line must be plugged in to the box for billing purposes. In one market Disney will experiment with a $29.99 activation fee as well.
The Moviebeam box will be regularly refreshed with new digital movies that are delivered to it not via digital cable, satellite or the Internet but through the old-fashioned pipeline of broadcast airwaves. Manufactured by Samsung Electronics, the receiver has a small but powerful antenna that resembles a tiny propeller. Through a process known as datacasting, Moviebeam perpetually transmits movies to the device's hard drive in tiny bits of data that travel alongside the normal broadcast stream of a local ABC or PBS station, without interfering with regular TV broadcasts. While the service currently uses the analog broadcast spectrum, it is equipped to take advantage of digital broadcasts when they become more common.
A collection of data structured and organized in a disciplined fashion so that access is possible quickly to information of interest. There are many ways of organizing databases. Most corporate databases are not one single, huge file. They are multiple databases related to each other by some common thread, e.g. an employee identification number. Databases are made up of two elements, a record and a field. A record is one complete entry in a database, e.g. Harry Newton, 205 West 19 Street, York, NY 10011, 212- 206-7140. A field would be the zip code field, namely 10011.
Databases are stored on computers in different ways. Some are comma delineated. They differentiate between their fields with commas ” like Gerry's record above. A more common way of storing databases is with fixed length records. Here, all the fields and all the records are of the same length. The computer finds fields by index and by counting. For example, Gerry's first name might occupy the first 15 characters. Gerry's last name might be the next 20 characters, etc. Where Gerry's names are too short to fill the full 15 or 20 characters, their fields are " padded " with specially- chosen characters which the computer recognizes as padded characters to be ignored. The most important thing to remember about databases is that all the common database programs, like dBASE, Paradox, Rbase, etc. don't automatically make backups of their files like word processing programs do. Therefore, before you muck with a database file ” sort it, index it, restructure it, etc. Please make sure you make a backup of the main database file.
A person who organizes, designs, implements and runs the company's databases. Since I personally believe databases ” especially of prospects and customers ” are pretty well a company's most important asset, this job of database administrator is very important.
DBA. A computer at MCI Worldcom that maintains the master file of Vnet translation information. The master file is created when a customer begins service and can be changed at anytime through CIM. The updated copies of the database are downloaded each night to the DAPs.
Database clustering is a technology that allows a bunch of computers connected together to work as one and serve a single relational database. The idea is that together they can create a fault-tolerant, high performance, scalable solution that's a low-cost alternative to large, expensive servers. Database clustering is also called real application clustering (RAC). When I wrote this it was new and relatively unproven. There are two common methods of clustering relational databases, known as " shared-disk " and "shared-nothing" clustering. IBM's DB2 Universal Database (DB2 UDB) uses a shared-nothing approach. In this architecture, each node in the cluster holds only one segment of the database, and the node also handles all of the computational work that corresponds to the data it stores. A master server assesses the task at hand and then parcels it out, distributing a portion of the job to each node that contains data to be processed . The task is then executed by all of the nodes in parallel, and the master server reports the result. Oracle uses shared disk clustering ” a design that's structured around a single large data store (for example, a disk array). Each node on the cluster has equal access to all of the information in the data store. Only the processing work is divided amongst them, and not the data itself. The result is particularly fault tolerant database. Even if one or more servers fails, all of the application data remains available to the other nodes. By comparison, if one node on a shared-nothing database crashes, all of the data stored on that node likewise goes offline, until a failover system can recover from the fault.
A specific type of system table that stores information about the structure of a particular database. Primarily used in relational databases to store the names and data types of the tables and columns in a database. Can also be known as a Lookup Table.
A software program which allows telephone users to find information on someone calling via the LCD window on their phone. This information comes to the user via CLID (Calling Line IDentification) or ANI (Automatic Number Identification). See also Class.
DBMS. Computer software used to create, store, retrieve, change, manipulate, sort, format and print the information in a database. Database management systems are probably the fastest growing part of the computer industry. Increasingly, databases are being organized so they can be accessible from places remote to the computer they're kept on. The "classic" database management system is probably an airline reservation system.
You have a database of your customers. You have information on your customers' buying habits. You slice and dice your database to find out which of your customers might be interested in purchasing new items and which items. For example, let's say you make clothes. 20% of your customers buy in "tall" mens sizes. Next time you make some tall mens ' clothes, you may want to tell those customers ” with an email or a direct mail catalog. That, in its simplest example, is called database mining or collaborative filtering.
One of the components of a database: a table, view, index, procedure, trigger, column, default, or rule.
A specialized computer that doles out database data to PCs on a LAN the way a file server doles out files. Where a traditional DBMS runs both a database application and the DBMS program on each PC on the LAN, a database server splits up the two processes. The application you wrote with your DBMS runs on your local PC, while the DBMS program runs on the database server computer. With a regular file server setup, all the database data has to be downloaded over the LAN to your PC, so that the DBMS can pick out what information your application wants. With a database server, the server itself does the picking, sending only the data you need over the network to your PC. So a database server means vastly less network traffic in a multi-user database system. It also provides for better data integrity since one computer handles all the record and file locking. See Server.
Datablades are components for particular types of data that plug into a central database, similar to the way razor blades snap into a razor . Informix is rewriting some of its databases so other companies can produce datablades.
A transmission method in which sections of a message are transmitted in scattered order and the correct order is re-established by the receiving workstation. Used on packet-switching networks. The Dow Jones Handbook of Telecommunications defines it as, "A single unacknowledged packet of information that is sent over a network as an individual packet without regard to previous or subsequent packets." Here's another definition I found. A finite-length packet with sufficient information to be independently routed from source to destination. In packet switching, a self-contained packet, independent of other packets, that carries information sufficient for routing from the originating data terminal equipment to the destination data terminal equipment, without relying on earlier exchanges between the equipment and the network. Unlike virtual call service, there are no call establishment or clearing procedures, and the network does not generally provide protection against loss, duplication, or misdelivery. Datagram transmission typically does not involve end-to-end session establishment and may or may not entail delivery confirmation acknowledgment. A datagram is the basic unit of information passed across the Internet. It contains a source and destination address along with data. Large messages are broken down into a sequence of IP datagrams. See Connectionless Mode Transmission.
The type of packet-switched network in which each packet is individually routed. This may result in a loss of sequence within a message because of alternate routing, or a loss of portions of a message because of packet elimination for congestion control. See Datagram.
The programmer and system house in Atlanta which provides several long distance carriers with value-added services ” what Sprint calls its SCADA system manufacturer.
A packet-switched network run in Denmark, Sweden, Finland and Norway and operated by their respective governments .
A name that once was a data service that provided digital, full-duplex data transmission at speeds of 300 bps through 19.2 Bps asynchronous and 1,200 through 64 Kbps synchronous. Datapath has built in autobaud and hand-shaking protocols.
A diagnostic tool for monitoring and capturing data transmissions which displays real-time transmissions of raw data in hexadecimal, binary, or character-oriented displays.
DataSPAN is generally characterized as a "fast packet" service and is based on frame relay standards recommended by the International Consultative Committee for Telephone & Telegraph (ITU) (now called the ITU-T) and the American National Standards Institute (ANSI). Northern Telecom has introduced DataSPAN as a new DMS SuperNode value-added, data communications service that is targeted toward connecting high-speed local area networks. Northern Telecom asserts that DataSPAN's rapid and efficient data transport assures reliable delivery and substantial performance improvement over current LAN interconnect solutions. DataSPAN switching and transmission delay is less than 3 ms per node; X.25 switching and transmission delay can be up to 50 ms per node. Using Frame Relay, wide-area packet switching can be accomplished with the same level of performance that is traditionally limited to complex, dedicated private-line networks. DataSPAN is accessed through standard DS-0 or DS-1 links.
Many voice mail systems will append the date and time of receipt of voice messages for their users/subscribers.
An Austrian packet-switched network in Austria and Germany and run by their respective governments.
The format employed to express the time of an event. The time of an event on the UTC time scale is given in the following sequence; hour, day, month, year; e.g., 0917 UTC, 30 August 1997. The hour is designated by the 24- hour system. UTC stands for Coordinated Universal Time, believe it or not.
See Direct-Access Test Unit.
Dumb Ass User.A term meaning user induced error in any technical application: computing, telecom or wherever mankind meets the mechanical. It's a stupid acronym. I don't make this stuff up.
First there is the motherboard. That's the main circuit board of a computer system. The motherboard contains edge connectors or sockets so other PC (printed circuit) boards can be plugged into it. Those PC boards are called Fatherboards. Some fatherboards have pins on them into which you can plug smaller boards. Those boards are called Daughterboards. In a voice processing system, you might have a Fatherboard to do faxing. And you might have a range of Daughterboards, which allow you to connect different types of phone connections. Different boards exist for standard analog tip and ring, digital switched 56, etc. See also Motherboard.
Same as Daughterboard.
See Distributed Authoring and Versioning.
Digital Audio Video Council. A voluntary SIG (Special Interest Group) organized to "favour the success of emerging digital audio-visual applications and services, by the timely availability of internationally agreed upon specifications of open interfaces and protocols that maximize interoperability across countries and applications/services." The current set of DAVIC 1.0 specifications are to further the deployment of broadcast and interactive systems that support initial applications such as TV distribution, near video on demand, video on demand, and basic forms of teleshopping. DAVIC is one of the organizations examining the developing specifications for VDSL (Very-high-bit-rate Digital Subscriber Line), which is intended for video applications. www.davic.org. See also Digital Video Broadcast.
A call center term. A historical pattern consisting of seven factors, one for each day of the week, that defines the typical distribution of call arrival throughout the week. Each factor measures how far call volume on that day deviates from the average daily call volume.
That component of the variance of a set of daily load measurements.
Decibel. One tenth of a Bel, with "Bel" referring to Alexander Graham Bell. A unit of measure of signal strength, usually the relationship between a transmitted signal and a standard signal source, known as a reference. The decibel was invented by the Bell System to express the gain or loss in telephone transmission systems. Loss in such systems was the result of signal attenuation in passive devices (e.g., conducted media such as copper cables, inductors and capacitors and radiated media such as the air between transmitting and receiving radio antenna). Gain in such systems is the result of active devices such as amplifiers and repeaters. The ultimate objective of measuring the loss in such a passive system is to compensate for it with measured gain accomplished by an active device in order to produce a signal at the receiver which is of the same intensity as the signal created by the transmitter.
Specifically, decibel is a logarithmic unit, which defines the level of gain or loss in signal strength in a circuit or link, or device, compared with a reference value. The logarithmic expression of gain or loss is much more effective for several reasons. First, the human ear interprets loudness (i.e., signal strength) on a scale much closer to a logarithmic scale than a linear scale. Second, the quantities measured often exhibit huge ranges of variation that can be expressed more conveniently in logarithmic , rather than linear, terms. A 10 dB gain (i.e., increase in signal strength) describes a ten-times increase. A gain of 3 dB means that the power of the signal was doubled ; loss of 3 dB (-3 dB gain) means that the power of the signal was halved. For a longer explanation, see Decibel.
Data Bus connector. Usually shown with a number that represents the number of wire conductors in the connector, e.g. DB-9 or DB-25, both of which are very common connectors to plug into serial ports on PCs. See DB-9, DB-15 and DB-25.
dB Loss Budget is the amount of light available to overcome the attenuation in the optical link and still maintain specifications.
This is the standard nine-pin RS-232 serial port on all laptop PC computers and most desktop computers today. The term DB-9 is used to describe both the male and female plug. So be careful when you order. See also the Appendix in this Dictionary for more information on the pinning of RS-232-C plugs. The above is contemporary usage, i.e. the way it's used today. In fact, it's wrong historically. The "D" originally described the shape of the housing. The second letter: A, B, C, D or E originally specified the size of the housing where the "E" is used somewhat like it's used as a drawing size (i.e., smaller than a "D"). There are connectors made with, e.g., size "B" housing with other than 9, 15 or 25 pins. Sometimes coax "pins" are included, which use up several little pin locations. See the Appendix in this dictionary for more information on the pinning of RS-232 plugs.
A standardized connector with 15 pins. It can be used in Ethernet transceivers. It can also be used for connecting VGA monitors . DB-15 is used to describe both the male and female plug. So be careful when you order. See also DB-9 for a longer explanation.
The standard 25-pin connector used for RS-232 serial data communications. In a DB-25 there are 25-pins, with 13 pins in one row and 12 in the other row. DB-25 is used to describe both the male and female plug. So be careful when you order. See also DB-9 and the Appendix in this dictionary for more information on the pinning of RS-232 plugs.
A connector with 60 pins in four rows (15 pins in each row).
IBM's relational database system that runs on System 370-compatible mainframes under the MVS operating system.