Block 2 Unit 4

Front 1

permit terminal-to-computer and computer-to-computer communications over an analog telephone line. Converts digital data into analog data at the tranmitting end and converts analog data back into digital data at the reciving end

Back 1

modems

Front 2

used in a wode area of applications with in the communication wold

Back 2

converters

Front 3

changes analog signals to a digital (binary) representation. Modems use this to change the carious voltage levels into a binary representation of voltages

Back 3

A/D converters

Front 4

change a set of digital binary numbers into a specific voltage proportional to the bin ary value. There purpoes is to convert digital signals into analog signals

Back 4

D/A conveters

Front 5

connect various types of cables that exist with in a network

Back 5

network media converters

Front 6

acts as a translator between workstations or networks that use different operating systems, communication protocols, data format structures or network hardware architectures by enabling the nodes to communicate with different types of networks or devices

Back 6

gateways

Front 7

connects workstations in the main frame network that would otherwise not recognize the workstation. Workstations appear as IBM 3270 (dumb) terminals to the mainframe host

Back 7

IBM host gateways

Front 8

translates messages from one vendors messaging appliation to another vendors application

Back 8

e-mail gateway

Front 9

devices that filter packets between LAN segments and are used in physical star and tree toplogies. Using these in a network will greatly reduce or eliminate collisions on a network

Back 9

switches

Front 10

the entire packets is recieved and placed into the buffer memeory, where an error check is performed and the packet is sent to the proper part for delivery

Back 10

store-and-forward

Front 11

does not perform a CRC check or store the entire packet. As soon as the address is recieved into the buffer, the frame is directed to the proper part for delivery with out being checked for errors

Back 11

cut-through

Front 12

sometimes referred to as modified cut-through. the switch checks the first 64bytes of a frame for fragmentation before forwarding the frame to the proper part for delivery

Back 12

fragmentfree

Front 13

a device that connects two ore more LAN segments to effectively make those segments one logical network. Provide filtering and forwarding services

Back 13

bridges

Front 14

operate at the OSI network layer and are used to connect two or more netowork segments or networks

Back 14

routers

Front 15

a date from many different types of equipment. encryption is done by hardware devices. the data is encrypted in order to be carried securley over leased lines, satellite, microwaves or radio signals.

Back 15

WIde band encryption

Front 16

informations from telephones. encryption is done by hardware devices. the data is encrypted in order to be carried securly over leased lines, satellite, microwaves or radio signals

Back 16

narrowband encryption

Front 17

is obtained by combining multiple signals, such as data and/or voice lines, onto one line. Encryption is done by hardware decives. the data is encrypted in order to be carried securley over leased lines, satellite, microwaves or radio signals.

Back 17

bulk encryption

Front 18

all types of incription plus the use of software encryption

Back 18

network encryption

Front 19

the means or way information travels from one location to another.

Back 19

communication mediums

Front 20

the physical environment through which data travels as it moves from one component or device to another.

Back 20

guided/bound media

Front 21

wireless. they have no physical constraints confining the signal to a set path. atmospheric conditions can impair your wireless transmissions, degrading both analog and digital signal quality

Back 21

unguided/unbound media

Front 22

has a solid center conductor, surronded by an insulating spacer that is surrounding a grounded shield of braided wire, foil or both. the shield minimizes electrical and radio frequency interference. the entire assembly is covered with an insulating and proective outer layer.

Back 22

Coaxial cabling

Front 23

COAX cable used in ethernet 10base5 networks. typically a bright color and is marked with black band every 2.5 meters to inicate proper placement of the transceiver called a media access unit (MAU)

Back 23

thicknet

Front 24

COAX cable used in ethernet 10base2 networks. this cable is cheaper, lighter, more flexible, and easier to install.

Back 24

thinnet

Front 25

most common media for netowork connectivity. limits signal degradation from electromagnetic interference (EMI) and radio frequency interference (RFI).

Back 25

Twisted-pair cable

Front 26

this cable combines the techniques of shielding and twisting of wires to protect against signal degradation. contains four pairs of wire. specified for use in ethernet network installations, reduces electrical noise both withing the cable and from outside the cable

Back 26

shielded twisted-pair (STP)

Front 27

has become the most economical choice amont networking cables. contains 8 insulated wires.

Back 27

unshielded twisted pair (UTP)

Front 28

voice-grade telephone wire. not suitable for data transmission

Back 28

category 1

Front 29

certified for data ransmission up to 4 Mbps

Back 29

category 2

Front 30

certified for data transmission up to 10 Mbps (ethernet standard)

Back 30

category 3

Front 31

rated for data transmission up to 16 Mbps (IBM token ring standard)

Back 31

category 4

Front 32

rated for data transmission up to 100 Mbos (fast thernet standard)

Back 32

category 5

Front 33

rated for data transmission up to 1000 Mbps (gigabit ethernet standard)

Back 33

category 6

Front 34

typically has a core diameter of 50 to 100 microns. this relatively large core allows many modes, or paths, of light to propagate down the optic path producing good coupling from inexpensive couples, connectors, and LED light soources. supports longer segment lengths than a twisted-pair wire.

Back 34

multi-mode fiber (MMF)

Front 35

uses a glass fiber that is approximately 10 microns in diameter and permits a single mode of light to be propagated using expensive lasers as the light source

Back 35

single-mode fiber (SMF)

Front 36

uses lasers to transmit and receive network signals. provides a relativily secure transmission medium when guided medium cannot be used

Back 36

light transmission

Front 37

the information you wish to transmit is superimposed onto an RF carrier, which increases power and range.

Back 37

fixed frequency signals

Front 38

the transmit signal frequency varies as the RF carrier frequency varies. this reduces noice interfernece

Back 38

spread spectrum signals

Front 39

a communication device that combines several data or voice signals for transmission over one signle medium. primary purpose is to save communications cost. provide error correction and data security.

Back 39

multiplexer

Front 40

combines several different data signals onto a single fiber optic cable.

Back 40

wave division multiplexing

Front 41

invloves the distirbution of multiple signals in the time domain, a digital process.

Back 41

time division multiplexing (TDM)