A-conditionIn a start-stop teletypewriter system, the significant condition of the signal element that immediately precedes a character signal or block signal and…
a-law algorithmA standard compression algorithm, used in digital communications systems of the European digital hierarchy, to optimize, i.e.
abandoned callA call in which the call originator disconnects or cancels the call after a connection has been made, but before the call is established.
abandonmentProcess by which the debtors estate would not benefit by the sale of certain property so the trustee will turn it back over to the debtor.
abbreviated addressAn address that has fewer characters than the full address, usually for special communications and other services or for certain users.
abbreviated address callingCalling that enables a user to employ an address having fewer characters than the full address when initiating a call.
abbreviated dialingA telephone service feature that (a) permits the user to dial fewer digits to access a network than are required under the nominal numbering plan, and (b)…
abortIn a computer or data transmission system, to terminate, usually in a controlled manner, a processing activity because it is impossible or undesirable for…
abrasiveAny of a number of hard materials, such as aluminum oxide, silicon carbide, and diamond, that are powdered and carefully graded according to particle…
absolute addressIn communications, computer, and data processing systems, an address that directly identifies a storage location without the use of an intermediate…
absolute delayThe time interval or phase difference between transmission and reception of a signal. 2.
absolute gainOf an antenna, for a given direction and polarization, the ratio of (a) the power that would be required at the input of an ideal isotropic radiator to…
absorptanceThe ratio of the luminous flux or absorbed radiant flux to the incident flux.
Absorption(ub-SORP-shun) The process of taking nutrients from the digestive system into the blood so they can be used in the body.
absorption bandA spectral region in which the absorption coefficient reaches a relative maximum, by virtue of the physical properties of the matter in which the…
Absorption CoefficientIn reference to a solar energy conversion devices, the degree to which a substance will absorb solar energy.
absorption indexA measure of the attenuation caused by absorption of energy per unit of distance that occurs in an electromagnetic wave of given wavelength propagating in…
absorption lossThat part of the transmission loss caused by the dissipation or conversion of electrical, electromagnetic, or acoustic energy into other forms of energy…
absorption modulationAmplitude modulation of the output of a radio transmitter by means of a variable-impedance circuit that is caused to absorb carrier power in accordance…
absorption peak1. The wavelength or frequency at which a particular substance absorbs the most power (or, where the attenuation of the propagated signal is the greatest)…
absorptivityIn a solar thermal system, the ratio of solar energy striking the absorber that is absorbed by the absorber to that of solar energy striking a black body…
abstract syntaxIn open systems architecture, the specification of application-layer data or application-protocol control information by using notation rules that are…
abstract syntax notation one (ASN.1)A standard, flexible method that (a) describes data structures for representing, encoding, transmitting, and decoding data, (b) provides a set of formal…
AbstractionAbstraction involves changing the interface of an object and exposing it in a more useful or appropriate form.
ac-dc ringingTelephone ringing that makes use of both ac and dc voltages and currents. Note: An alternating current may be used to operate a ringer and direct current…
acceptIn data transmission, the condition assumed by a primary or secondary station upon correct receipt of a frame for processing.
AcceptanceThe written approval of the buyer's offer by the seller.
acceptance angleIn fiber optics, half the vertex angle of that cone within which optical power may be coupled into bound modes of an optical fiber.
acceptance coneIn fiber optics, the cone within which optical power may be coupled into the bound modes of an optical fiber.
acceptance limit (AL)The bound on performance that is allowed at service turnup or interexchange carrier (IC) acceptance of a circuit or connection, or when corrective action…
acceptance patternOf an antenna, for a given plane, a distribution plot of the off-axis power relative to the on-axis power as a function of angle or position.
acceptance testA test of a system or functional unit to ensure that contractual requirements are met.
acceptance testingOperating and testing of a communication system, subsystem, or component, to ensure that the specified performance characteristics have been met.
acceptance trialA trial carried out by nominated representatives of the eventual military users of the weapon or equipment to determine if the specified performance and…
accepted interferenceInterference at a higher level than that defined as permissible interference and which has been agreed upon between two or more administrations without…
accessright, opportunity, or means of finding, using, or retrieving information
access arrangementAn arrangement to transport access traffic between an end office and an IC POT (interexchange carrier point of termination) and may be either direct…
access attemptThe process by which one or more users interact with a telecommunications system to enable initiation of user information transfer.
access barred signalIn a communications system, a signal sent in the backward direction to indicate that a call will not be completed because of a call-originator or a…
access categoryA class to which a user, such as a person, program, process, or equipment, of a system may be assigned, based on the resources each user is authorized to…
access channelA designated part of the information transfer capability having specified characteristics, provided at the user-network interface. [T1.667-1999]
access chargeA charge levied on a power supplied, or its customer, for access to a utility's transmission or distribution system.
access codeThe preliminary digits that a user must dial to be connected to a particular outgoing trunk group or line. 2.
access connectionIn ISDN technology, a connection (using either the B-Channel or a logical link on the D-Channel) established between the user equipment and a packet-mode…
access controlThe mechanisms for limiting access to certain information based on a user's identity and membership in various predefined groups.
access control listA list that identifies the users who can access the associated object and that specifies the user's access rights to that object.
access control mechanismIn security, a hardware, software, or firmware feature, operating procedure, or management procedure that (a) permits authorized access to a system, such…
access control messageA message that is a user request, a resource controller response, or a request/response between resource controllers.
access control policy1. A set of rules, part of a security policy, by which human users, or their representatives, are authenticated and by which access by these users to…
access denialAccess failure caused by the issuing of a system blocking signal by a communications system that does not have a call-originator camp-on feature. 2.
access digitIn automatic direct outward telephone dialing, a digit, often a 1, or a 9, that (a) enables access to an outside facility, e.g.
access failureIn a communications system, an unsuccessful access that results in termination of an access attempt in any manner other than initiation of user…
access functionA set of processes in a network that provides for interaction between the user and a network. [T1.667-1999]
Access GatewayThe Access Gateway provides an access interface between multiple types of line side services and devices and the packet network.
access groupA group of one or more stations having identical rights to use the available resources on a PBX, network or host computer.
access levelIn security, the level of authority required from an entity to access a protected resource.
access lineA transmission path between end user terminal equipment and a switching center. 2. A channel between an end user's network interface and local end office.
access listIn information systems (IS), a compilation of users, programs, or processes and the access levels and types to which each is authorized. [INFOSEC-99] 2.
access nodeIn switching systems, the point where user traffic enters and exits a communications network.
access originatorThe functional entity responsible for initiating a particular access attempt. Note: An access attempt can be initiated by a source user, a destination…
access pathThe steps required to obtain the use of a system or device. Note: Examples of access paths are (a) the operations required of a database management system…
access periodIn security, a segment of time, generally expressed in days or weeks, during which specified access rights prevail. [INFOSEC-99]
access permissionAll of a subject's access rights with respect to some object. [2382-pt.8]
access phaseIn an information-transfer transaction, the phase during which an access attempt is made.
access pointA point where connections may be made for testing or using particular communications circuits. 2.
access profileIn security, a profile that associates each user with a list of protected objects that the user may access. 2.
access providerAn organization that provides users with access to a computer network. [2385-35] 2.
access requestA control message issued by an access originator for the purpose of initiating an access attempt. 2.
access right1. Permission for a subject to access a particular object for a specific type of operation.
access service areaA geographic area established for the provisioning and administration of telecommunications service.
access systemIn communications, computer, and data processing systems, a program that (a) allows an operator to call up different parts of the program package and (b)…
access tandemA telephone company or centralized equal access provider switching system that provides a concentration and distribution function for originating or…
access timeIn a telecommunication system, the elapsed time between the start of an access attempt and successful access.
access typeIn computer security, a type of operation specified by an access right. Note: Examples of access type are "read," "write," "execute," "append," "modify,"…
access-denial timeThe time between the start of an access attempt and access failure caused by access denial, i.e., system blocking.
accessibilityAn aggregate measure of how reachable locations are from a given location. The ACCESSIBILITY command computes values for accessibility as a function of…
AccountabilityThe principle that individuals using a facility or a computer system must be identifiable.
AccountingRecording of the exercise of access rights to types of information specified in the System Security policy.
accounting managementIn network management, a set of functions that (a) enables network service use to be measured and the costs for such use to be determined and (b) includes…
AccreditationIf a Marketplace health plan is approved, this is the “seal of approval” given to the plan by an independent organization to show that the plan meets…
Accrediting AuthorityOfficial with the authority to formally assume responsibility for operating an information system at an acceptable level of risk to agency operations…
AccumulatorA component of a heat pump that stores liquid and keeps it from flooding the compressor.
AccuracyDepartment of Defense parlance for the notion that information has been maintained and transferred in such a way as to be inviolate (the information has…