Box - used to describe statements in ontologies; T-Box statements describe a system in terms of controlled vocabularies, for example, a set of classes and properties. T-box statements are sometimes associated with object-oriented classes.
- Browse Related Terms: ABox, anonymous class, asserted hierarchy, CamelBack notation, defined class, inferred hierarchy, OWL DL, OWL-Full, OWL-Lite, owl:Thing, Pellet, probe class, Reasoner, restriction, SHER, T, Web Ontology Language (OWL)
Abbreviation for tera (1012). See International System of Units.
- Browse Related Terms: ALU, ARU, bits per inch (b/in), MAU, PDU, SI, T, TCU, VDU, vu
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A standards-based protocol used with Exchange Data Conferencing. Clients such as Microsoft NetMeeting are T.120 compatible. [Exchange 2000]
- Browse Related Terms: DSAccess, IMAP4 (Internet Messaging Access Protocol version 4), IMPP (Instant Messaging Presence Protocol), LSA (Link State Algorithm), MTA (message transfer agent), NNTP (Network News Transfer Protocol), POP3 (Post Office Protocol version 3), routing service, RVP (Rendezvous Protocol), SMTP (Simple Mail Transfer Protocol), T.120, Virtual server
- The generic designator for any of several digitally multiplexed telecommunications carrier systems.
Note 1: The designators for T-carrier in the North American digital hierarchy correspond to the designators for the digital signal (DS) level hierarchy. See the associated table below.
Note 2: T-carrier systems were originally designed to transmit digitized voice signals. Current applications also include digital data transmission.
Note 3: If an "F" precedes the "T", a fiber optic cable system is indicated at the same rates.
Note 4: The table below lists the designators and rates for current T-Carrier systems.
Note 5: The North American and Japanese hierarchies are based on multiplexing 24 voice-frequency channels and multiples thereof, whereas the European hierarchy is based on multiplexing 30 voice-frequency channels and multiples thereof. See table below.
T-Carrier Systems North American Japanese European (CEPT) Level zero (Channel data rate) 64 kb/s (DS0) 64 kb/s 64 kb/s First level 1.544 Mb/s (DS1) (24 user channels) 1.544Mb/s (24 user channels) 2.048 Mb/s (30 user channels) (Intermediate level, North American Hierarchy only) 3.152 Mb/s (DS1C) (48 Ch.) - - Second level 6.312 Mb/s (DS2) (96 Ch.) 6.312 Mb/s (96 Ch.), or 7.786 Mb/s (120 Ch.) 8.448 Mb/s (120 Ch.) Third level 44.736 Mb/s (DS3) (672 Ch.) 32.064 Mb/s (480 Ch.) 34.368 Mb/s (480 Ch.) Fourth level 274.176 Mb/s (DS4) (4032 Ch.) 97.728 Mb/s (1440 Ch.) 139.268 Mb/s (1920 Ch.) Fifth level 400.352 Mb/s (5760 Ch.) 565.148 Mb/s (7680 Ch.) 565.148 Mb/s (7680 Ch.)
Note 1: The DS designations are used in connection with the North American hierarchy only.
Note 2: There are other data rates in use, e.g., military systems that operate at six and eight times the DS1 rate. At least one manufacturer has a commercial system that operates at 90 Mb/s, twice the DS3 rate. New systems, which take advantage of the high data rates offered by optical communications links, are also deployed or are under development.
- Browse Related Terms: access connection, adaptive channel allocation, automatic sounding, basic access, broadband exchange (BEX), Capacity, channel gate, Channelization, circuit transfer mode, common control, common equipment, common-channel interoffice signaling (CCIS), embedded operations channel (EOC), multidestination mode (MD), positioned channel, primary channel, primary rate interface (PRI), restricted channel, secondary channel, statistical multiplexing, T-carrier, terminal
A passive optical coupler having three ports (three fibers). Note 1: Two isolated inputs may be combined into one output; or one input, into two isolated outputs. Note 2: The amount of coupling loss, usually expressed in dB, between ports is determined by the design and construction of the coupler. [After FAA] Synonyms directional coupler, splitter, tee coupler.
- Browse Related Terms: Amplifier, attenuator, bandwidth (of an optical fiber), medium access unit (MAU), noise current, noise voltage, optical detector, optical junction, photon noise, quantum efficiency, quantum noise, shot noise, source efficiency, spectral responsivity, star coupler, T-coupler, transfer function
Test and Evaluation.
- Browse Related Terms: ACETEF, Air Force Operational Test and Evaluation Center (AFOTEC), Capstone Test and Evaluation Master Plan (Capstone TEMP), CDT&E, COMOPTEVFOR, CTE, CTEIP, DOT&E, DT&E, DTSE&E, Follow-On Operational Test and Evaluation (FOT&E), FOT&E, IOT&E, JT&E, LFT&E, Life Cycle of a Weapon System, MCOTEA, OPTEC, OPTEVFOR, OT&E, PAT&E, RDT&E, Research, Development, Test, and Evaluation (RDT&E), Sys T&E, T&E, Technical Evaluation, TECOM, TEIPT, TEMP, TEP, TER, TERC, TESP, TEV, TEWG, TT&E, USAOTEC, USATECOM
For basic rate access in an Integrated Services Digital Network (ISDN) environment, a user-to-network interface reference point that (a) is characterized by a four-wire, 144-kb/s (2B+D) user rate, (b) accommodates the link access and transport layer function in the ISDN architecture, (c) is located at the user premises, (d) is distance sensitive to the servicing network terminating equipment, and (e) functions in a manner analogous to that of the Channel Service Units (CSUs) and the Data Service Units (DSUs).
- Browse Related Terms: attachment unit interface (AUI), medium interface connector (MIC), medium interface point (MIP), message register leads, originating connection, R interface, S interface, S reference point, T-interface, terminal adapter, Trunk Gateway, U reference point, V reference point, wireline access mode
In Integrated Services Digital Networks (ISDN), the conceptual point dividing NT2 and NT1 functional groupings in a particular ISDN arrangement.
- Browse Related Terms: basic rate interface (BRI), broadband ISDN (B-ISDN), operator service access point (OSAP), operator services, synchronous transfer mode, T reference point, transfer mode, U interface, Wide area network (WAN)
A full-duplex digital transmission facility that is composed of transmission media (optical or metallic) and regenerators that carry one DS1 signal. [After T1.408-1990]
- Browse Related Terms: air-spaced coaxial cable, equivalent gauge, field wire, fortuitous conductor, metallic circuit, metallic voltage, open wire, rope lay conductor, slope equalizer, symmetrical pair, T1 line, unbalanced line, voltage rating, wireline