T

T-CONNECTOR

A T-shaped device with two female and one male connectors.

T/P SWITCH

A switch (on the AT&T Merlin Legend system) that you use to test and program your phone.

T1

A long-haul transmission medium capable of transmitting information at 1.544 Mbps. Generally, information on a T1 medium is multiplexed into 56- or 64-Kbps. The T1 circuit is a point-to-point full-duplex digital circuit that originally was meant for carrying digitized voice. You can connect several point-to-point circuits to form a T1 network. The T1 circuit can use a variety of media besides copper, such as coaxial cables, fiber optics, infra red, 18- and 23-Gigahertz microwave radio or satellite links. T1 networks provide a physical level connection with a data rate of 1.544 Mbps. This rate is in the range that can run workstation applications efficiently across T1 networks.

T3

28 T1 lines, 44736 million bits per second.

TACACS-DS

TACACS-Database Service

TACNEWS

TAC News

TAG

Technical Advisory Group

TAGGED IMAGE FILE FORMAT

(TIFF) A bit map file format for describing and storing color and gray-scale images.

TAIWAN 4 VIRUS

Gradually slows workstation.

TANSTAAFL

There Ain't No Such Thing As A Free Lunch

TAPI

See Windows Telephony Application Programming Interface.

TAS

Telephone Answering Service

TB

Terabyte

TCB

Transmission Control Block Or Trusted Computing Base

TCP

See Transmission Control Protocol.

TCP/IP

See Transmission Control Protocol/Internet Protocol.

TCP/IP TRANSPORT SOFTWARE

Software residing in the operating system, including a set of device drivers. These drivers have an interface with the MLID/ODI drivers at the bottom layer, and support the Berkeley socket APIs at the top layer.

TCPCON

TCP/IP Console

TCXO

Temperature Compensated Oscillator

TDA

The transmitted data signal for RS-232-A output from the device.

TDB

The differential return signal for TDA for transmitting RS-422-A data. See TDA.

TDM

Time Division Multiplexing

TDMA

Time Division Multiple Access

TDT

The Dream Team

TE

See ISDN Terminal Equipment.

TE1

See ISDN Terminal Equipment type 1.

TE2

See ISDN Terminal Equipment type 2.

TECHINCAL SUPPORT

What a software company promises you'll get if you buy from them: So-called free advice on how to use their program. "So called" because, when you call for help, either the line is busy or the company has gone bankrupt.

TED

(Text EDitor) Univ. of Washington ASCII screen editor used for UNIX, VMS, and DOS. FTP from ftp.u.washington.edu, filename ted.tar.gz

TELECOM VIRUS

Writes a variant of the Anti-Tel virus into the partition table of the workstation's hard disk.

TELECONFERENCE

A general term for a meeting not held in person. Usually refers to a multi-party telephone call, set up by the phone company or private source, which enables more than two callers to participate in a conversation. The growing use of video allows participants at remote locations to see, hear, and participate in proceedings, or share visual data.

TELEMETRY

Transmission and collection of data obtained by sensing real-time conditions.

TELEPHONY SERVER

The Telephony Server supports CSTA in a Novell NetWare environment. The Telephony Server may also refer to a Novell file server that has been loaded with and runs the Telephony Server software.

TELEPHONY SERVICES DRIVER INTERFACE

A connection between a Driver NLM and the Tserver NLM using a function call interface to pass messages between modules.

TELNET

The Internet-standard terminal access application-level protocol. Telnet supports character terminals, block terminals (for example, DEC VT220), and graphics terminals. It is used for remote login on an internet network.

TELNET PROTOCOL

See Telenet.

TEMPEST

See Transient Electromagnetic Pulse Surveillance Technology.

TERMINAL

An input/output device that is a slave of a CPU, such as with a minicomputer or mainframe terminal. Terminals are not used in the distributed computing environment of a PC network. The term 'terminal' sometimes is used incorrectly to describe a 'workstation.' See Workstation.

TERMINAL SERVER

A concentrator that facilitates communication between hosts and terminals.

TERMINATE-AND-STAY-RESIDENT PROGRAM

(TSR) A program running under DOS that remains loaded in memory even when it is not running so that it can be quickly be invoked for a specific task performed while any other application program is operating.

TERMINATING RESISTORS

Resistance values that match the impedance of the selected cable

TFT COLOR DISPLAY

See Thin Film Transistor Color Display.

TFT COLOR LCD DISPLAY

A low power display design combining TFT and LCD display technology to provide crisp, bright color without generating much heat. See Thin Film Transistor Color Display.

TFTP

Trivial File Transfer Protocol

TH

Transmission Header Or Trouble History

THE

(The Hessling Editor) Runs on UNIX, DOS, and OS/2, and looks lile an editor found on a CMS system

THG

The Humble Guys

THICK - ETHERNET

See 10BASE5.

THICK COAXIAL CABLE

(no RG equivalent), 50 ohm

THICKNET

See 10BASE5.

THICKWIRE

Half-inch diameter coax cable. See 10BASE5.

THIN - ETHERNET

See 10BASE2.

THIN CLIENT/THICK SERVER

Desktop computers are dumbed down, with onyl enough intelligence to negotiate networks. The thin clients will seek out applications and data, but will only borrow them. The actual data and applications will live on the main computers, called thick network servers. Also called weak client/strong server.

THIN COAX

See 10BASE2.

THIN FILM TRANSISTOR COLOR DISPLAY

Use a precise array of active light-emitting semiconductors to display a crisp, bright color picture, even in daylight and darkness. Can typically display 512 colors.

THINNET

See 10BASE2.

THINWIRE

See 10BASE2.

THP

The Hill People

THREADS

A way of organizing and displaying the sequence of articles that make up a conversation by linking articles on the same subject. The News protocol and many news readers have built-in support for this mode of operation.

THREE FINGER SALUTE

To restart (reset) a running computer, in DOS by pressing [Ctrl]+[Alt]+[Del].

THROUGHPUT

The total useful information processed or communicated in a specified amount of time. Data compression increases the throughput of your modem by allowing you to send more information in the same number of bits.

TIA

Thanks In Advance (also AtDhVaAnNkCsE)

TIC

Tongue in cheek

TIC

See Token Ring Interface Coupler.

TICKS

RIP packet information field that contains an estimate of time delay for available LANs and WANs. See Routing Interior Protocol.

TIFF

TSee agged Image File Format.

TIGA

Texas Instruments Graphics Architecture - based display adapter

TIME

Time Server Protocol

TIME BOMB

See Bomb.

TIME CODE

A frame-by-frame address code time reference recorded on the spare track of a videotape or inserted in the vertical blanking interval. It is an eight-digit number encoding time in hours, minutes, seconds, and video frames (e.g.:02:04:48:26).

TIME DELAY

Described in nanoseconds per foot (ns/ft), time delay represents the amount of time required for a signal to travel through the cable. It is directly proportional to the square root of the dielectric constant of your cable. Hence, the lower the dielectric constant, the faster the signal can be transmitted through the cable. See Velocity of Propagation..

TIME SHARING OPTION

(TSO) An IBM host-based teleprocessing environment. This is used to access/edit host-based files, etc.

TIME SLICE

A brief period of time in which a process is given access to the processor. Each second is divided into 18.3 time slices; multiple tasks can be scheduled for processing in these slices, yet outwardly appear to be occurring simultaneously. (See multitasking.)

TIME SLICE INTERVAL

(IBM PC LAN) A predefined, but variable interval of time used to measure the amount of time that a server devotes to foreground and background tasks. Each time slice interval is eqivalent to x timer ticks, a timer tick being 1/18.2 seconds long. (See multitasking.)

TIME TO LIVE

(TTL) The amount of time an IP router holds a datagram before discarding it.

TIMESLICING

A method of multitasking that allocates CPU attention to tasks in fractions of a second, making it appear to users that the multitasking operations are happening simultaneously. Tasks are either assigned priority levels or processed in sequence to maintain order.

TINT

Another name for hue.

TIP

"+" side of the voice phone line pair, also called "a".

TL

IC part number prefix indicating Texas Instruments, Inc.

TLA

Three Letter Acronym

TLAP

TokenTalk Link Access Protocol

TLI

Transport Layer Interface

TMS380SRA

Source Routing Accelerator. An integrated circuit that provides source routing frame filtering at the maximum rate allowed on 802.5 token rings.

TNO

The New Order

TOKEN BUS

See IEEE 802.4 Token-Passing Bus

TOKEN FRAME

A structure that contains data on a token ring network. When a node has data to transmit, it replaces a free token with a token frame.

TOKEN RING

See IBM Token Ring LAN.IBM Token Ring LAN

TOKEN RING INTERFACE COUPLER

(TIC) Device on IBM 3725 or 3745, allowing the use of Token Ring topology for communication with local terminal emulation devices. The IBM 3174 cluster controller provides the same capability by way of its optional token-ring adapter. In many cases, the IBM 3174 will communicate with both the host and the terminal emulation devices via the Token Ring.

TOKEN RING, TYPE 1

Use Type 1 Token Ring cable (Shielded twisted pair) with IBM style universal data connectors, which give you greater distances with passive devices. Also supports greater speeds (16Mbps), with fewer problems on the network. See IBM Token Ring LAN.

TOKEN RING, TYPE 3

Use Category 3, 4, or 5 unshielded twisted-pair cable with easy-to-use modular connections. Type 3 cabling is much more flexible. Because the cable is not shielded, however, less distance is attainable and more network problems can occur. See IBM Token Ring LAN.

TOKEN-PASSING BUS

See IEEE 802.4 Token-Passing Bus.

TOKEN-PASSING NETWORKS

The token in a token-passing network is a specialized packet that controls the right of any node to access the LAN. The node in possession of the token has control of the LAN medium. The token is passed from node to node in a manner that creates a ring, which may be logical (ARCnet) or physical (IBM Token-Ring). The ring is fault tolerant, in that it provides maintenance for ring initialization at each node, lost token recovery, and new station addition and deletion from the logical or physical ring (called reconfiguration). Token-passing networks have been in wide use since 1977 when DataPoint Corporation introduced Attached Resource Computer Network (ARCnet). ARCnet is a token-passing network. The IEEE 802 committee has its own version of the token-passing ring network, described under IEEE 802.5. The IEEE committee has also defined a token-passing bus network in the IEEE 802.4 standard. Since token-passing networks use a token to control all network traffic, the message packet collisions inherent with CSMA networks are eliminated. As opposed to the statistical nature of a CSMA scheme, token-passing is a deterministic access scheme. There are specific rules by which each node is governed when using the token.

TOKEN-PASSING RING

A network topology in which the next logical node receiving the token is also the next physical location on the ring. The access protocol used in Token Ring networks. Token-passing ring uses a ring or star-wired ring topology to pass bits of data around a physically wired ring. Three frame types exist, the first of which is a token which grants exclusive use of the ring when received. The station that has the token transfers messages onto the ring. The messages are passed between stations on the ring sequentially bit by bit in order, with each station receiving and retransmitting each message. The destination node copies the information as it passes, and the message is removed by the originator. See IEEE 802.5

TOKEN-RING

See Token-Passing Ring

TONE DIALING

One of two methods of dialing the telephone. (The other is pulse dialing.) With tone dialing, the modem sends tones of different frequencies to represent the telephone numbers. Tone dialing is normally associated with push-button (touch-tone) phones and is also called Dual Tone Multi-Frequency (DTMF) dialing.

TOPIC

The specific part of the server application that the client application is talking to. Most of the time, the client application specifies a topic when it starts the conversation. But if the topic is not specified, all possible topics respond and it is the client's responsibility to chose between them.

TOPOLOGY

The layout or design of cabling on a network. Three basic topologies are used in LANs today: linear-bus, star-bus, and star-wired ring. Variations such as hierarchical star-bus and distributed star-bus topologies are also used. Though other topologies are used in networks, including mesh and tree topologies, they are not commonly employed in LANs. The term 'topology' often is used by Novell and in the industry to identify a single physical LAN (or network address). This usage is vague, confusing, and inconsistent with industry standards. Moreover, it confounds clear and concise explanations of network addressing.

TP

See Transaction Program

TP

Transport Protocol

TP-TCP

ISO Transport Service on top of the TCP

TRAFFIC FILTERING

A configurable LAN Distance feature that reduces the amount of LAN traffic that flows across a connection to only the data frames that are needed by the participating workstations. See Filtering.

TRAINING

See CCITT V.32bis.

TRANSACTION PROGRAM

(TP) In general, a program that processes units of work. In particular, an APPC program that uses the APPC API to communicate with a partner on a remote system.

TRANSCEIVER

An electrical LAN device that transmits and receives bits of data from a network. In an Ethernet LAN, the transceiver acts as a gate, closing the circuit to enable data to be transmitted when the cable is free and opening the circuit to disable transmissions when other activity is sensed on the cable. It also detects collisions (transmissions from other nodes during a transmission) and stops the transmission. Transceivers also introduce 'jabber control' to prevent one node from dominating the network, and Signal Quality Error (which is turned off in modern Ethernet LANs).

TRANSIENT ELECTROMAGNETIC PULSE SURVEILLANCE TECHNOLOGY

(TEMPEST) Computers and other electronic equipment release interference to their surrounding environment. You may observe this by placing two video monitors close together. The pictures will behave erratically until you space them apart. Although most of the time these emissions are simply annoyances, they can sometimes be very helpful. Tempest is the US Government program for evaluation and endorsement of electronic equipment that is safe from eavesdropping.

TRANSLATING BRIDGE

A type of LLC bridge that translates between different frame types and access protocols using 802.2 protocol. (See LLC, Bridge, and Frame.)

TRANSMISSION CONTROL LAYER

The fourth layer of the SNA network. This layer creates, manages and ends sessions.

TRANSMISSION CONTROL PROTOCOL

A virtual circuit connection-oriented protocol.

TRANSMISSION CONTROL PROTOCOL / INTERNET PROTOCOL

A set of networking protocols developed in the 1970s and funded by the U.S. Government's Defense Advanced Research Projects Agency (DARPA). TCP/IP was the second generation of the previously established DARPANET, which had been developed for weapons research, development, and procurement by the Department of Defense. TCP/IP includes Transport Control Protocol, which is a connection-oriented transport protocol that includes transport, session, and presentation layer protocol functions equivalent to layers 4, 5, and 6 of the OSI Model and Internet Protocol, and a widely used routable network protocol that corresponds to layer 3 of the OSI Model. User Datagram Protocol (UDP) can be substituted in cases where connectionless datagram service is desired. TCP/IP is more than these two protocols; it is an entire protocol stack that includes protocols for file transfers (FTP), terminal emulation services (telnet), electronic mail (SMTP), address resolution (ARP and RARP), and error control and notification (ICMP and SNMP). TCP/IP is used extensively in many computer systems because it is nonproprietary-free from royalties. Its use was mandated by Congress in 1988, in computer systems for many government agencies and contract situations. TCP/IP is used in the Internet, a huge government and research internetwork spanning North America and much of the world, which was opened to commercial use in the summer of 1991. These factors have caused TCP/IP use to grow, making it the most commonly used set of network protocols. A set of network protocols that has become an industry standard in engineer ing, government, and educational local area net work environments. The TCP/IP protocol family includes transport, file transfer, terminal emulator, messaging, and network management definitions. TCP/IP is used in both LANs and WANs. Unlike other WAN protocols, TCP/IP is not point-to-point oriented and is used to tie many hosts into internetworks. These two protocols are equivalent to OSI network and transport protocols; however, higher layer protocols also are defined in these specifications. IP is routable and provides the routing capability for this multiple host internetworking. TCP/IP is extensively used to tie together thousands of computers over various types of links to form the Internet across T-1 links. TCP/IP is widely used in many networked systems so that interoperability is accomplished. TCP/IP is used as the transport/network protocol in many routers. TCP/IP network and transport protocols are equivalent to layers 3 and 4 of the OSI model. User Datagram Protocol (UDP) can be substituted in cases where connectionless datagram service is desired. TCP/IP is more than these two protocols; it is an entire protocol stack that includes FTP, TELNET,SMTP, ARP, RARP, ICMP, and SNMP.

TRANSMIT PASSWORD

A character string added to all outgoing OSI packets.

TRANSPARENT APPLICATION INTEGRATION

The ability to manipulate information with a variety of applications within a single document, without moving from one application to another to produce the desired results. This is implemented as Object Linking and Embedding in Windows 3.1.

TRANSPARENT BRIDGE

A MAC-layer bridge. (See Bridge and MAC-Layer Bridge.)

TRANSPORT CONTROL PROTOCOL / INTERNET PROTOCOL

See Transmission Control Protocol/Internet Protocol.

TRANSPORT LAYER

The fourth layer of the ISO OSI model. This layer handles layer the sequencing and guaranteed delivery of packets.

TRAP DOOR

A mechanism that allows the software developer to sneak back into the system, circumventing normal system protection. Sometimes programmers design these trap doors for testing and debugging the system. Although ordinarily removed before the system is released, back doors are sometimes left byaccident or design. In the 1983 movie War Games, for example, the protagonist enters into the NORAD computer system through a trap door left by its creator.

TREAT

Trouble Report Evaluation and Analysis Tool

TRICHROMATIC

The technical name for RGB representation of color to create all the colors in the spectrum.

TROJAN HORSE

A program code fragment that hides itself inside another independent program and performs a disguised function. Trojan horses are used by viruses and worms to escape detection. Just as the Greeks came out from hiding after their wooden horse was brought inside Troy, once inside the system, the virus or worm does its damage. When an authorized user performs the apparent function, the trojan horse performs the unauthorized function as well (often usurping the privileges of the user).

TRSI

Tristar Red Sector Inc.

TRU

Top Cell Radio Unit

TRUNK

A communication channel between switching devices or central offices.

TRUNK-1

Trunk-1 Protocol

TRUNK-2

Trunk-2 Protocol

TSAPI

See Novell's Telephony Services API.

TSDI

See Telephony Services Driver Interface:

TSERVER

The specific module that manages the routing of CSTA requests and responses between a client application and the appropriate PBX driver. The Tserver NLM is part of the Telephony Server. Manages 'Telephony' and 'OA&M' requests from clients (over the LAN). The Tserver will confirm that each client is administered for the requested service, CSTA or OA&M messages and authenticate some CSTA (but not OA&M) requests, and route the requests to the appropriate PBX Driver.

TSO

See Time Sharing Option.

TSR

See Terminate-and-Stay-Resident program.

TTL

See Time to Live.

TWIST

The ratio of the level of the high-frequency DTMF signal component to the level of the low-frequency signal component. Most modern receivers can handle level differences of +4 to -8 dB.

TWISTED-PAIR

(22/24 gauge), 150 ohm Cabling that consists of lightly insulated copper wire, twisted into pairs and bundled into sets of pairs. The twists enhance the wire's capability to resist crosstalk (bleeding of signal from one wire to the next).This cabling is used extensively in phone systems and many network topologies, including Novell's /68 systems, OmniNet, ARCnet, IBM Token-Ring, and Ethernet. This cable is available in two distinct forms: unshielded twisted pair (UTP) and shielded twisted pair (STP, or TP for short). It is important to realize that twisted pair is susceptible to any kind of electrical interference. Three properties of the cable itself also affect the performance of twisted-pair: attenuation, capacitance, and crosstalk. (See Attenuation, Capacitance, and Crosstalk) The combined effects of attenuation, capacitance, and crosstalk serve to inhibit network communications over twisted-pair cable. For example, cabling that has both a high attenuation and a high capacitance can be practically useless for digital transmissions. However, unshielded twisted pair (UTP) is best suited for high-speed computer network communications. This is because the alternative, shielded twisted pair, absorbs or attenuates the signal so that signal loss is greater over shorter distances. Although this makes it easier to comply with FCC regulations, shielded twisted pair can have severe distance limitations when it is used in computer networks. See 10BASE-T

TWO-WAY ALTERNATE (HALF-DUPLEX)

(HDX) 1) A mode of operation for a point-to-point or multi-point baseband link with two physical circuits, in which messages or transmission blocks can be sent in one direction or the other, but not both at the same time. 2) Contrasted with Two-Way Simultaneous.

TWO-WAY SIMULTANEOUS (FULL-DUPLEX)

(FDX) 1) A mode of operation for a point-to-point link with two physical circuits, in which messages or transmission blocks can be sent in both directions at the same time. 2) Contrasted with Two-Way Alternate.

TXD

Transmitted Data signal in RS-232-C. Carries serialized data output from the device..

TYPE

Refers to the physical size of the PC Card. There are three types of cards that have the same length and width (54 mm x 85.6 mm). The cards differ in thickness in the center, but have identical thickness at the connector end and along the rails. This lets you use all three types in the same PCMCIA slot, if the slot is thick enough in the center. See Type I, Type II, and Type III.

TYPE I

A 3.3 mm thick PC that is used for memory enhancements, such as Flash memory cards. See also PC Card and Type.

TYPE II

A 5 mm thick PC Card that is used for I/O features such as modem, LAN, and host communications. See also PC Card and Type.

TYPE III

A 10.5 mm thick PC Card that is used for memory enhancements or I/O capabilities that require more space, such as rotating media and wireless communication devices. See also PC Card and Type.

TYPEFACE

A complete grouping of related fonts.