transverse resolutionIn a facsimile receiver, the dimension that (a) is perpendicular to a scanning line and (b) is the smallest recognizable detail of the image produced by…
trapdoor1. A hidden software or hardware mechanism, usually created for testing and troubleshooting, that may be used to circumvent computer security. [2382-pt.
trapped electromagnetic waveAn electromagnetic wave that enters a layer of material that is surrounded on both sides by a layer of material of a lesser refractive index such that, if…
traveling waveA wave that (a) propagates in a transmission medium, (b) has a velocity determined by the launching conditions and the physical properties of the medium…
tree searchIn a tree structure, a search in which it is possible to decide, at each step, which part of the tree may be rejected without a further search.
tree structureA hierarchical organization in which a given node is considered to be an ancestor of all the lower level nodes to which the given node is connected.
TRI-TACTri-Service Tactical Digital Communications System.
TRI-TAC equipmentEquipment that (a) accommodates the transition from current manual and analog systems to fully automated digital systems and (b) provides for message…
triaxial cableA specialized form of coaxial cable, circular in cross-section and consisting of (a) a center conductor, often a solid wire but sometimes braided…
tributary circuitA circuit between a tributary office and a toll switchboard or intertoll dialing equipment in a toll center city. [47 CFR Pt.36-A]
tributary officeA local office which is located outside the exchange in which a toll center is located, which has a different rate center from its toll center and which…
tributary stationIn a data network, a station other than the control station. 2. On a multipoint connection or a point-to-point connection using basic mode link control…
trim effectIn a crystal oscillator, the degradation of frequency-vs.-temperature stability, and marked frequency offset, resulting from frequency adjustment which…
triple data encryption algorithm (TDEA)An encryption algorithm whose key consists of three DES (Data Encryption Standard) keys, which is also referred to as a key bundle.
triple precisionCharacterized by the use of three computer words to represent a number in accordance with required precision.
tripletA sequential group of three nucleotides in DNA or RNA. See: codon.
tristimulus valuesIn a given trichromatic system, the amounts of the three reference color stimuli required to match the light considered in a given chromatic system.
Trojan horseA computer program with an apparently or actually useful function that contains additional (hidden) functions that surreptitiously exploit the legitimate…
Tropospheric ScatterThe propagation of electromagnetic waves by scattering as a result of irregularities in the physical properties of the troposphere.
tropospheric waveA radio wave that is propagated by reflection from a place of abrupt change in the dielectric constant, or its gradient, in the troposphere.
True PowerThe actual power rating that is developed by a motor before losses occur.
truncated binary exponential backoffIn carrier sense multiple access with collision avoidance (CSMA/CA) networks and in carrier sense multiple access with collision detection (CSMA/CD)…
truncationThe deletion or omission of a leading or a trailing portion of a string in accordance with specified criteria.
truncation errorIn the representation of a number, the error introduced when one or more digits are dropped.
trunkIn a communications network, a single transmission channel between two points that are switching centers or nodes, or both. 2.
trunk encryption device (TED)A bulk encryption device used to provide secure communications over a wideband digital transmission link.
Trunk GatewayThe Trunk Gateway provides an access interface between traditional Public Switched Telephone Network (PSTN) circuit-based networks and packet networks.
trunk groupTwo or more trunks of the same type between two given points.
trunk group multiplexer (TGM)A time-division multiplexer that combines individual digital trunk groups into a higher rate bit stream for transmission over wideband digital…
TrustA fiduciary relationship in which a person, called a trustee, holds title to property for the benefit of another person, called a beneficiary.
trusted computer system (TCS)1. [An] information system (IS) employing sufficient hardware and software assurance measures to allow simultaneous processing of a range of classified or…
trusted computing base (TCB)1. [ The] totality of protection mechanisms within a computer system , including hardware , firmware , and software , the combination of which is…
trusted distribution[A] method for distributing trusted computing base (TCB) hardware, software, and firmware components that protects the TCB from modification during…
trusted functionA function whose correct operation is relied upon for the security policy to be upheld [CESG].
trusted functionalityThat which is perceived to be correct with respect to some criteria, e.g., as established by a security policy [7498-2].
trusted identification forwarding[The] identification method used in information system (IS) networks whereby the sending host can verify an authorized user on its system is attempting a…
trusted networkThe subnetwork formed by an association of interconnected Trusted Network Interface Units and one or more Access control Systems [CESG].
trusted network interface unit (TNIU)TNET (see Trusted Network above) will be realized by the development of a number of components including the TNIU and ACS.
Trusted PathA mechanism by which a person at a terminal can communicate directly with the Trusted Computing Base.
trusted process[A] process that has privileges to circumvent the system security policy and has been tested and verified to operate only as intended. [INFOSEC-99]
trusted recovery1. [The] ability to ensure recovery without compromise after a system failure. [INFOSEC-99] 2.
trusted regionPart of a system that contains trusted functions [CESG].
trusted software1. [The] software portion of a trusted computing base (TCB). [INFOSEC-99] 2. The software portion of a Trusted Computing Base [TCSEC].
trusted third-party1. A security authority trusted by communicating entities with respect to specific security-related activities ( e.g., for the purpose of authentication).
truth tableAn operation table for a logic operation. 2. A table that describes a logic function by listing all possible combinations of input values and indicating…
TSEC nomenclature[In security, the] system for identifying the type and purpose of certain items of COMSEC material. [INFOSEC-99]
TTYA TTY (teletypewriter) is a communication device used by people who are deaf, hard-of-hearing, or have severe speech impairment.
TTY/TDDA unique telecommunication device for the deaf, using TTY principles.
tuningSelecting the number and type of AMIs to run a Hadoop job flow most efficiently.
tunnelingIn computer networking, a technique for connecting two networks via a third, while totally isolating the connected traffic from other traffic in the third…
Turing machineA mathematical model of a device that changes its internal state and reads from, writes on, and moves a potentially infinite tape, all in accordance with…
turnaround timethe total time a Service Request is in the laboratory, from its receipt at Evidence Intake until a formal report is issued
turnkeyPertaining to a procurement process that (a) includes contractual actions at least through the system, subsystem, or equipment installation phase and (b)…
twin cableA cable composed of two parallel conductors separated from each other by a ribbon-like insulator or encased by a foam insulator. Synonym twin-lead.
twinplexA frequency-shift-keyed (FSK) carrier telegraphy system in which four unique tones, i.e.
twistIn telephony, a change, as a function of temperature, in the shape of the frequency-vs.-attenuation response curve, i.e.
twisted pairA pair of individually insulated conductors (wires) twisted together and treated as an entity in the transmission of electrical signals or power (e.g.
two-out-of-five codeA binary-coded decimal notation in which (a) each decimal digit is represented by a binary numeral consisting of five binary digits of which two are of…
two-part codeCode consisting of an encoding section, in which the vocabulary items (with their associated code groups) are arranged in alphabetical or other systematic…
two-person controlContinuous surveillance and control of positive control material at all times by a minimum of two authorized individuals, each capable of detecting…
two-person integrity (TPI)[A] system of storage and handling designed to prohibit individual access to certain COMSEC keying material by requiring the presence of at least two…
two-pilot regulationIn frequency-division multiplexed (FDM) systems, the use of two pilot frequencies within a band so that the differential change in attenuation with…
two-tone keyingIn telegraphy systems, keying in which the modulating wave causes the carrier to be modulated with a single tone for the "mark" and modulated with a…
Type 1 Interconnection Service ProviderA wireless SP that utilizes Type 1 (trunk side with line treatment) interconnection with another SP's end office switch.
type 1 productClassified or controlled cryptographic item for securing classified and sensitive U.S. Government information, when appropriately keyed.
type 2 productUnclassified cryptographic equipment, assembly, or component, endorsed by the National Security Agency, for use in national security systems as defined in…
type 3 algorithm[A] cryptographic algorithm that has been registered by the National Institute of Standards and Technology (NIST) and published as a Federal Information…
type 4 algorithm[An] unclassified cryptographic algorithm that has been registered by the National Institute of Standards and Technology (NIST), but not published as a…