Chapter 8: Communications
Terms in this set (84)
buying and selling goods electronically.
provides a very-low-cost alternative to long-distance telephone calls using electronic voice and video delivery.
provides very efficient direct text communication between individuals using short electronic messages.
provides a fast, efficient alternative to traditional mail by sending and receiving electronic documents.
the process of sharing data, programs, and information between two or more computers.
a concept related to using computer networks to link people and resources.
are electronic systems that transmit data from one location to another
These devices act as an interface between the sending and receiving devices and the communication channel.
Data transmission specifications
a measurement of the width or capacity of the communication channel.
used for standard telephone communication ; While effective for transmitting text documents, it is too slow for many types of transmission, including high-quality audio and video.
used in special leased lines to connect midrange computers and mainframes as well as to transmit data over long distances. This bandwidth is capable of very-high-speed data transfer.
widely used for DSL, cable, and satellite connections to the Internet. Several users can simultaneously use a single broadband connection for high speed data transfer.
widely used to connect individual computers that are located close to one another. Like broadband, it is able to support high-speed transmission. Unlike broadband, however, this can only carry a single signal at a time.
rules for exchanging data between computers
hypertext transfer protocol secure
widely used to protect the transfer of sensitive information.
transmission control protocol/Internet protocol
involve (1) identifying sending and receiving devices and (2) breaking information into small parts, or packets, for transmission across the Internet.
addresses to deliver e-mail and to locate websites
domain name server (DNS)
that converts text-based addresses to IP addresses
Information sent or transmitted across the Internet usually travels through numerous interconnected networks
reformatted or broken down into small parts
continuous electronic waves
represent the presence or absence of an electronic pulse—the on/off binary signals
process of converting from digital to analog
converting from analog to digital
The speed with which modems transmit data varies
WWAN (wireless wide area network) modem. Almost all computers today have built-in wireless modems
creates high-speed connections using the system unit's USB or Ethernet port.
DSL (digital subscriber line)
standard phone lines to create a high-speed connection directly to your phone company's offices. These devices are usually external and connect to the system unit using either a USB or an Ethernet port.
Digital subscriber line (DSL) service
provided by telephone companies using existing telephone lines to provide high-speed connections.
ADSL (asymmetric digital subscriber line)
one of the most widely used types of DSL. DSL is much faster than dial-up.
provided by cable television companies using their existing television cables. These connections are usually faster than DSL.
showing up in some areas, but it is a new technology and not widely available
Satellite connection services
use satellites to provide wireless connections. While slower than DSL and cable modem, these connections are available almost anywhere using a satellite-receiving disk.
cellular service providers
including Verizon, AT&T, Sprint, and T-Mobile, support voice and data transmission to wireless devices using cellular networks. These networks have gone through different generations.
started in the 1980s using analog radio signals to provide analog voice transmission service
Second-generation mobile telecommunications (2G)
started in the 1990s using digital radio signals
Third-generation mobile telecommunications (3G)
started in the 2000s and provided services capable of effective connectivity to the Internet, marking the beginning of smartphones.
Fourth-generation mobile telecommunications (4G)
has begun to replace 3G networks in some areas with providers using LTE (Long Term Evolution) connections to provide faster transmission speeds.
are an essential element of every communication system
consists of pairs of copper wire that are twisted together.
a high-frequency transmission cable, replaces the multiple wires of telephone lines with a single solid-copper core.
transmits data as pulses of light through tiny tubes of glass.
short-range radio communication standard that transmits data over short distances of up to approximately 33 feet ; widely used for wireless headsets, printer connections, and handheld devices.
uses high-frequency radio signals to transmit data
communication uses high-frequency radio waves. It is sometimes referred to as line-of-sight communication because microwaves can only travel in a straight line. Because the waves cannot bend with the curvature of the earth, they can be transmitted only over relatively short distances.
WiMax (Worldwide Interoperability for Microwave Access)
a new standard that extends the range of Wi-Fi networks using microwave connections.
communication uses multiple antennae (cell towers) to send and receive data within relatively small geographic regions (cells).
communication uses satellites orbiting about 22,000 miles above the earth as microwave relay stations
a term relating to sending data to a satellite
refers to receiving data from a satellite.
Global positioning system (GPS)
devices use that information to uniquely determine the geographic location of the device.
uses infrared light waves to communicate over short distances
communication system that connects two or more computers so that they can exchange information and share resources. Networks can be set up in different arrangements to suit users' needs
any device that is connected to a network. It could be a computer, printer, or data storage device.
node that requests and uses resources available from other nodes. Typically, a client is a user's personal computer.
node that shares resources with other nodes. Dedicated servers specialize in performing specific tasks. Depending on the specific task, they may be called an application server, communication server, database server, file server, printer server, or web server.
a specialized server that manages resources, such as user accounts, for an entire network.
any computer system connected to a network that provides access to its resources.
a node that forwards or routes data packets from one network to their destination in another network.
central node that coordinates the flow of data by sending messages directly between sender and receiver nodes. A hub previously filled this purpose by sending a received message to all connected nodes, rather than just the intended node.
network interface cards
these are expansion cards located within the system unit that connect the computer to a network. Sometimes referred to as a LAN adapter
network operating system
control and coordinate the activities of all computers and other devices on a network. These activities include electronic communication and the sharing of information and resources
a computer specialist responsible for efficient network operations and implementation of new networks.
local area networks
Networks with nodes that are in close physical proximity—within the same building
a device that allows one LAN to be linked to other LANs or to larger networks
personal area network (PAN)
a type of wireless network that works within a very small area—your immediate surroundings
Metropolitan area networks
span distances up to 100 miles. These networks are frequently used as links between office buildings that are located throughout a city.
wide area networks
countrywide and worldwide networks. These networks provide access to regional service (MAN) providers and typically span distances greater than 100 miles. They use microwave relays and satellites to reach users over long distances—
nodes have equal authority and can act as both clients and servers
use central servers to coordinate and supply services to other nodes on the network
way of coordinating the sharing of information and resources.
this topology is the newest type and does not use a specific physical layout (such as a star or a tree) ; requires that each node have more than one connection to the other nodes
each device is connected to a central node, either directly or through one or more other devices.
each device is connected directly to a central network switch.
each device is connected to two other devices, forming a ring.
each device is connected to a common cable called a bus or backbone, and all communications travel along this bus.
A network can be arranged or configured in several different ways.
describes how a network is arranged and how resources are coordinated and shared. It encompasses a variety of different network specifics, including network topologies and strategies.
private network within an organization that resembles the Internet ; use browsers, websites, and web pages
private network that connects more than one organization.
consists of hardware and software that control access to a company's intranet and other internal networks.
intrusion detection system
work with firewalls to protect an organization's network. These systems use sophisticated statistical techniques to analyze all incoming and outgoing network traffic.
virtual private network
create a secure private connection between a remote user and an organization's internal network.