A
2B4Q
AAL
Adaptation
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| Term | Description |
A |
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2B4Q
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2 Binary 4 Quarternary, a line encoding technique which uses two bits to represent four variations in amplitude and polarity. It is the enabling technology behind HDSL. |
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AAL
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ATM Adaptation Layer, the element in an ATM network that converts between the source information format (voice, data, video) and ATM cells. Also, a protocol layer within ATM that controls the conversion process between the source and destination. |
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Adaptation
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Conversion of the data structure in order to segment applications into ATM cell payloads. |
| ADM – add drop multiplexer | A circuit that synchronously multiplexes and/or demultiplexes signals between levels of a digital hierarchy, such as DS1 and DS3, and gives easy access to components of a digital signal. Such a device enables termination of part of the capacity of a high-speed line at an intermediate site while the capacity thus freed is used for transmission to a third site. |
| AIN - Advance Intelligent Network | A network in which complex call processing and routing, and network management are provided by means of centralized databases at a few points, rather than from a comparable database at every switching station. A high speed signaling network carries information on call setup to individual switching stations. |
| Analog | A category of devices and circuits in which a signal varies continuously in amplitude or frequency. |
| ARPA | Advanced Research Projects Agency |
| ASCII - American Standard Code for Information Interchange | A widely used 7-bit character code for data communications and data processing. An eighth bit is added for parity checking. As a standard, ASCII enables digital communications between computers and similar systems, regardless of manufacturer. |
| ATDNet | Advanced Technology Demonstration Network |
| ATM - Asynchronous Transfer Mode | A communications technology for switching and transmission that efficiently and flexibly organizes information into fundamental building blocks known as cells. ATM’s powerful flexibility lies in its ability to provide high-capacity switching for all types of information, including data, video, image and voice. ATM does this by taking these various digital inputs and translating (i.e. adapting) them, into fixed-size, 53-byte cells. |
| B | UP |
| B-ISDN | Broadband Integrated Services Digital Network, a carrier service designed to support all forms of information exchange, based on a sophisticated system of signaling for call control, cell-based transmission using ATM, and broadband data rates. |
| Backbone | A transmission facility, or arrangement of such facilities, designed to interconnect lower-speed distribution channels or clusters of dispersed users or devices. |
| Bandwidth | The range of signals that can be transmitted by a switching device, transmission facility or a transmission medium. Bandwidth is expressed in Hertz (Hz) for analog and bits per second (bps) for digital. |
| Broadband | The quality of a communications link having essentially uniform response over a given range of frequencies. A communication link is said to be broadband if it offers no perceptible degradation to the signal being transported. |
| Broadband Multiplexer | An information concentrator with output trunk(s) that can operate at T1, multi-T1, T3, Sonet, or ATM rates, by substituting one module for another. |
| C | UP |
| CAPS | Competitive access providers. |
| Carrier | Broad term used to describe privately-owned and state-owned entities around the world that provide transmission facilities used to carry voice and data communications from one point to another. |
| CCITT | Consultative Committee for International Telephony and Telegraphy |
| Cell Relay | Generic definition of the transfer and switching of information (voice, data, LAN or multimedia) in fixed length packets, known as cells. Also known as cell switching, FastPacket or ATM. |
| Cellular System | A fully automatic, wide-area, high-capacity radio telephone network made up of a group of RF coverage areas called cells. As a subscriber passes from cell to cell, a series of hand-offs maintains smooth call continuity. |
| CO-Central Office | The switching centers or central switching facilities of telephone companies providing local service. Users are physically connected to the central office over copper wires or, in some cases, over fiber optic cable. |
| CIR - committed information rate | The minimum guaranteed throughput required by a customer set on each PVC and SVC. |
| Constant Bit Rate | Digital information that has a constant transmission rate over time, and typically supports synchronized timing between source and destination. |
| CPE - customer premises equipment | All telecommunications terminal equipment located on the customer premises, including telephone sets, private branch exchanges (PBXs), data terminals, and customer-owned coin-operated telephones. |
| D | UP |
| DBAS - Data Base Administration System | An operations support system that maintains a database of billed-number screening data, including calling card, collect, and bill-to-third-number information. The system also handles auditing and fraud reporting. A workstation-based version is available. |
| DEMON | Delivery of Electronic MultimediaOver Networks |
| Dial-up | Describing the process of, or the equipment or facilities involved in, establishing a temporary connection via the switched telephone network. |
| Digital | A method of storing, processing and transmitting information through the use of distinct electronic or optical pulses. Digital transmission and switching technologies employ a sequence of these pulses to represent information, and differs from analog transmission, which uses a continuously variable signal. |
| Digital Hierarchy | A system of standardized transmission rates for digital signals using time-division multiplexing techniques. The rates are: DSO, 64 kbit/s (one voice channel); DS1, 1.544 Mbit/s (24 voice channels); DS1C, 3.152 Mbit/s (48 voice channels); DS2, 6.312 Mbit/s (96 voice channels); DS3, 44.736 Mbit/s (672 voice channels), and DS4NA, 139.264 Mbit/s (2016 voice channels). An additional level, DS4 (274.176 Mbit/s, or 4032 voice channels), is no longer used. |
| DSO | The basic element of the carrier digital hierarchy called the T-carrier system, a 64 kbps information channel that can be used to transport digital data or PCM-coded voice. |
| DXI | Data exchange Interface, an interface between a data device and a cell-based service DSU/CSU used to offload the process of cell creation and processing from a router or data system. |
| E | UP |
| E1 | A standard trunk speed of 2.048 Mbps. Used primarily in Europe. |
| F | UP |
| FastPacket | Also known as cell switching, cell relay, or ATM. |
| FCC | Federal Communications Commission |
| Fiber | A fine glass strand, the thickness of a human hair, used to convey light-based information. |
| Frame Relay | A multiplexing data service based on fast transport of formatted information frames, without flow control or error correction. |
| G | UP |
| Gigabit | A billion bits. Gbps, or Gigabits per second, is a measure of transmission speed or throughput associated with ATM technology. The amount of data or traffic that passes through an ATM switch is usually measured in gigabits. At a rate of 1 Gigabit, 139 500-page novels could be transmitted in a second, and a high resolution x-ray could be sent in less than a tenth of a second. |
| Glass | A general term applied to a wide variety of chemical formulations. Glasses are amorphous solids. |
| GUI | graphic user interface |
| H | UP |
| HSSI - High-Speed Serial Interface | A standard serial interface designed for operation at broadband data rates. |
| I | UP |
| Interactive | Describing an application in which the user becomes involved in an inquiry-response process, and which typically is multimedia in nature. |
| Internetworking | Connecting LANs across a WAN. |
| ISDN - Integrated Services Digital Network | A network architecture that enables end-to-end digital connections. The network supports diverse services through integrated access arrangements and defines a limited set of standard, multipurpose interfaces for equipment vendors, network providers, and customers. Interworking with a public switched telephone network is retained. |
| ISO | The International Standards Organization, located in Paris, is devoted to developing standards for international and national data communications, as well as standards to ensure quality in manufacturing. The US. representative to the ISO is the American National Standards Institute (ANSI). |
| ITU | International Telecommunications Union |
| L | UP |
| LIDB - Line Information Data Base | An application program that resides on a service control point (SCP) and provides validation information for use in alternate billing services, such as telephone calling cards. LIDB contains up-to-date records of all working lines, calling card numbers, and other data required for validation services. The acronym LIDB is often pronounced "lid-bee". |
| Local Area Network (LAN) | A user-owned and operated data transmission facility connecting devices - such as personal computers, workstations, printers and mass storage devices - within a limited geographical area, such as a building or group of collocated Buildings (campus). |
| M | UP |
| Megabit | A million bits. Mpbs, or Megabits per second, is a measure of transmission speed commonly associated with traditional public and private multiplexer-based networks. At a rate of 1 megabit per second, a 500-page novel could be transmitted in about seven seconds, and a high resolution x-ray in about 80 seconds. |
| Migration | The movement, or path, from one generation of networking technology to the next. |
| MTBF - Mean Time Between Failures | The average length of time between failures on a system. |
| Multiband | The ability to provide both narrowband and broadband access interfaces switching infrastructures with transparent interworking between interfaces. |
| Multimedia | A term widely used to describe applications in which data, images, video and voice are integrated within the application itself. ATM technology is expected to be the key enabler for these applications. |
| Multiplexer | A device or circuit that combines several signals onto a single line. |
| Multiplexing | Techniques to combine several communications channels into one facility to be shared among many users, thus reducing the cost per user dramatically. |
| N | UP |
| Narrowband | A communications channel of restricted bandwidth, often resulting in degradation of the transmitted signal. |
| NII | National Information Infrastructure |
| NNI - Network to Network Interface | A standard interface between two different network providers or carriers which may have dissimilar equipment. |
| P | UP |
| PCM | Pulse Code Modulation, the original strategy employed by carriers to convert analog voice information to digital form. PCM generates a 64 kbps signal (DSO). |
| PCS - Personal Communications Service | A short-range wireless communications service that enables users to make and receive calls offered over a personal communications network (PCN). Radio signals are carried between portable handsets and radio base stations that connect the signals to a public switched network. |
| PTT - Post, Telephone and Telegraph | A generic term for a government agency that in many countries supplies and maintains the infrastructure of a basic telecommunications network. |
| Port | The entry point into the frame relay network. |
| POTS - Plain Old Telephone Service | Basic telephone service without any enhanced features. It is the common term for residential telephone service. |
| Public Carrier | A company that provides the public (corporate customers) use of its network for a fee. |
| PVC - Permanent Virtual Circuit | A permanent logical pathway between two points created by a frame or cell protocol, and used by a communications device as though it were a "real" wire or leased carrier circuit. |
| R | UP |
| RBOC - Regional Bell Operating Company | One of the seven companies formed by the break-up of AT&T - Example: NYNEX. |
| Router | A frame or packet-oriented interconnection device capable of handling multiple protocols to link different LANs together. |
| Routing | The physical path, circuit group, and switching systems through which telecommunications traffic flows. |
| S | UP |
| Scalability | The extent to which a product, family of products, system or architecture can accommodate differences in network requirements that arise out of differences in size. For example, remote offices may require only a limited number of ports, to accommodate a few phone lines, a LAN connection, fax, traditional data and possibly dial-up video for teleconferencing. Total bandwidth requirements probably won’t exceed the T-1 rate of 1.5 Mbps. At large central sites, which may be connected to remote sites all over the world, bandwidth requirements can easily reach hundreds of Megabits, even Gigabits. A scalable networking solution should be able to address this range of needs. |
| SDH - Synchronous Digital Hierarchy | The international structure for optical transmission standards, corresponding to the U.S. Sonet standards. However, SDH starts at the 155Mbps level and increases in 155 Mbps multiples. |
| SMDS - Switched Multimegabit Data Service | Represents one of the first broadband services and operates over MANs. Offers switched LAN-like performance over the public network using cell relay techniques. |
| SONET - Synchronous Optical Network | A standard for the multiplexing and transmission of broadband information in optical form, so that low-speed components of the optical channel can be easily extracted. |
| SS7 - Signaling System 7 | An internationally standardized protocol for high-speed digital data communication between intelligent nodes. |
| STM - Synchronous Transport Module | The basic unit of the SDH structure, corresponding to the STS element of SONET, and providing a 155 Mbps service level. |
| STS - Synchronous Transport Signal | The basic unit of structure in the SONET standard, defining a service frame consisting of 9 rows and 90 columns, each containing 8 bits of information repeated 8,000 times per second. |
| SVC - Switched Virtual Circuit | A circuit set up on a call-by-call basis. A channel established on demand by network signaling used for information transport between two locations, lasting only for the duration of the transfer. The data communication’s equivalent of a dialed telephone call. |
| Switch | A device that opens or closes circuits or selects the path or circuits to be used for transmission of information. |
| T | UP |
| T1 | A time division multiplexing technique in which a number of channels are concentrated onto a transmission facility operating at the rate of 1.544 Megabits per second. Used primarily in North America and some Asia Pacific countries. |
| T1/E1 | The ability to send ATM standard compliant traffic over T1 or E1 lines. |
| T3 | A 45 (44.736) Mbps member of the carrier digital hierarchy, consisting of 28 T1s. |
| TAXI - Transparent Asynchronous Transmitter/ Receiver Interface | An ATM premises interface based on the physical-level optical standard used for FDDI, operating at 100 Mbps. |
| Time-Division Multiplexing (TDM) | A transmission technique which allow multiple signals to be combined on one transmission line using fixed bandwidth allocation. |
| Transmission | The transfer of electric power, signals, or intelligence from one location to another by wire, fiber optic, or radio means. |
| TRP | Technology Reinvestment Project |
| TSS | Telecommunications Standardization Sector |
| Twisted Pair | A pair of insulated copper wires used in transmission circuits to provide bi-directional communications. The wires are twisted about one another to minimize electrical coupling with other circuits. Paired cable is made up of a few, to several thousand, twisted pairs. |
| U | UP |
| UNI - User/ Network Interface | A standard or interface used to connect a communication user to a carrier service or private network. |
| V | UP |
| VAN - Value Added Network | A public carrier that provides value added services (e.g. E-mail, X.25) in addition to use of its network for a fee. |
| VOD | Video-on-demand |
| VT - Virtual Tributary | A sub-element of a SONET payload structured to carry the information normally contained in a T1 digital trunk. There is a VT for each of the elements in the T1 hierarchy. |
| W | UP |
| WAN - Wide Area Network | A user-owned and operated transmission facility connecting a number of communication devices - such as telephones, LANs, fax machines, etc. - over an extended geographical area, such as between different cities or countries. |
| Wideband | Information consisting of multiple DSOs greater than one, up to 24. |
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