Computer 9

Latency

the time it takes a signal to travel from one location to another on a network.

Personal Communications Services

(FCS) is term used to identify all wireless digital communications.

global positioning systems

(GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the receivers geographic location. Used to: find location, create a map, ascertaining the best route between two points, locating a lost person or stolen object, monitoring the movement of a person or object, determining altitude, and calculating speed.

public switched telephone network

(PSTN) is the worldwide telephone system that handles voice-oriented telephone calls.

Communication Process

1 - sending device initiates an instruction to transmit data, instructions or information. 2 - Communications device connects the sending device to a communications channel (ex: modem). 3 - Communications channel, transmission media, is what the data, instructions, or information travel on (cable television lines and telephone lines). 4 - communication device connects the communications channel to a receiving device. 5 - receiving device accepts the transmission of data, instructions, or information

Wireless messaging services

Mobile devices use three techniques: test messaging, picture/video messaging, and wireless instant messaging. The type of messaging depends on the wireless internet provider (WISP) which you choose.

Microwaves

are radio waves that provide a high-speed signal transmission. fixed wireless. microwave station: an earth based reflective dish that contains the antenna, transceivers, and other equipment necessary for microwave communications.

peer to peer internet

P2P, describes an internet network on which users access each other's hard disks and exchange filed directly over the internet, know as file sharing.

clients

are other computers and mobile devices on the network that rely on the server for its resources.

ring network

a cable forma closed loop with all computers and devices arranged along the ring.

Wireless access point

a central communications device that allows computers and devices to transfer data wirelessly among themselves or to transfer data wirelessly to a wired network.

Network

a collection of computer's and devices connected together via communications devices and transmission media. advantages: facilitating communications, sharing hardware, sharing data and information (EDI: electron data interchange), sharing software (network license: legal agreement that allows multiple users to access the software on server simultaneously. site license: a legal agreement that permits users to install the software on multiple computer), transferring funds (EFT electronic funds transfer). VAN (value-added network): a third-party business that provides networking services such as secure data and information transfer, storage, e-mail, and management reports.

Router

a communications device that connects multiple computers or other routers together and transmits data to its correct destination on a network. hardware firewall: prevents unauthorized users from accessing files and computers, many routers are protected by a built in firewall.

Hub/switch

a device that provides a central point for cables in a network.

Text Messaging

a mobile device with test messaging, also called SMS (short message service) capability allows users to send and receive short text messages, typically fewer then 300 characters, on a phone or other mobile device or computer. Mobile to mobile, mobile to e-mail, web to mobile, Mobile to provider (Common short code [csc] which is a four or five digit number assigned to a specific content or wireless service provider).

Ethernet

a network standard that specifies no central computer or device on the network (nodes) should control when data can be transmitted: that is each noted attempts to transmit data when it determines the network is available to receive communication. Based on bus. Physical configuration. Fast Ethernet --> gigabit Ethernet --> 10-gigabit Ethernet --> 40-gigabit Ethernet --> 100-gigabit Ethernet

Computer Communications

a process in which two or more computers or devices transfer data, instructions, and information.

Wireless Instant Messaging

a real-time internet communications service that allows wireless mobile devices to exchange messages with one or more mobile devices or online users. mobile to mobile mobile to personal computer web to mobile

dial-up lone

a temporary connection that uses one or more analog telephone lines for communications.

star network

all of the computers and devices (nodes) on the network connect to a central device, thus forming a star. Central connection know as hub or switch.

extranet

allows customers or suppliers to access part of its intranet.

Server

also call host computer, controls access to the hardware, software, and other resources on the network and provides a centralized storage are for programs, data, and information.

cybercafe

also known as internet café, is a coffeehouse, restaurant, or other location that provides personal computers with internet access to its customers.

ATM

asynchronous transfer mode, is a service that carries voice, data, video, and multimedia at very high speeds. will replace T3

bus network

consists of a single central cable to which all computer and other devices connect. It is a physical cable that connects the computers.

Coaxial cable

consists of a single copper wire surrounded by at leas three layers: (1) an insulating material, (2) a woven or braided metal, and (3) a plastic out coating.

Fiber-optic cable

consists of dozens or hundreds of thin strands of glass or plastic that use light to transmit signals. Each strand is called an optic fiber, and is as thin as a human hair.

Transmission media

consists of materials or substances capable of carrying one or more signals.

Twisted-pair cable

consists of one or more twisted-pair wires bundled together. they are twisted together to reduce noise. Noise: an electrical disturbance that can degrade communications.

Communications software

consists of programs that 1) help users establish a connection to another computer or network, 2) manage the transmission of data, instructions, and information, #) provide an interface for users to communicate with one another.

Types of servers

dedicated servers: perform a specific task and can be placed with other dedicated servers to perform multiple tasks. file servers: stores and manages files print server: manages printers and documents being printed. database server: stores and provides access to a database network server: manages network traffic. web server: is a computer that delivers requested web pages to your computer.

network standard

defines guidelines that specify the way computers access the medium to which they attached, the type of medium used, the speeds used on different types of networks, and they type of physical cable and/or the wireless technology.

web services

describes standardized software that enable programmers to create applications that communicate with other remote computers over the internet or on an internal business network. ex: third-party vendors can use web services to communicate with their online retailer's web site to manage their inventory levels. mashup: a web application that combines services from two or more sources, creating new application.

network architecture

design of computers, devices, and media in network. Either client/server or peer-to-peer.

peer-to peer network

each computer, peer, has equal responsibilities and capabilities sharing hardware, data, or information with other computers on the peer-to -peer network. less then 10 computers.

FTTP

fiber to the premises, uses fiber-optic cable to provide extremely high-speed internet access to a user's physical permanent location. FTTH (fiber to the house), FTTB (fiber to the building)

ISDN line

for small business and home user, provides faster transfer rates than dial-up line. Integrated services Digital Network. ADSL (asymmetric digital subscriber line): is a type of DSL that supports faster transfer rates when receiving data (downstream) than when sending data (upstream).

voice mail

function much like an answering machine, allows someone to leave a voice message for one or more people. voice mailbox: a storage location on a hard disk in the voice mail system. visual voice mail: users can view message details such as the length of calls and, in some cases, read message contents instead od listening to them.

Home network

homes that connect multiple computers and devices. intelligent home network: extends the basic home network to include features such as lighting control, thermostat adjustment, and a security system.

Wireless transmission media

infrared, broadcast radio, cellular radio, microwaves, and communications satellites.

digital modem

is a communications device that sends and receives data and information to and from a digital line. ISDN modem: sends digital data and information from a computer to an ISDN line and receives digital data and information fro ISDN. DSL modem: sends digital data and information from a computer to a DSL line and receives digital data and information from a DSL line. Cable modem: aka broadband modem, is a digital modem that sends and receives digital data over the cable television. Runs in on a single line then splitter split to TV and cable modem.

Cellular radio

is a form of broadcast radio that is used widely for mobile communications. 1g analog 2g, 3g, 4g, digital and faster, generations

Bluetooth

is a network standard, specifically a protocol, that defines how tow Bluetooth devices use short-range radio waves to transmit data.

Communications satellite

is a space station that receives microwave signals from an earth based station, amplifies the signals, and broadcasts the signals back over a wide area to any number of earth-based stations. Uplink: earth to satellite. downlink: satellite to earth.

dedicated line

is a type of always-on connection that is established between two communications devices.

intranet

is an internal network that uses internet technologies. small version of the internet that exist within an organization.

T-carrier line

is any of several types of long-distance digital telephone lines that carry multiple signals over a single communications line. T1 line, fractional T1, T3

communications device

is any type of hardware capable of transmitting data, instructions, and information between a sending device and a receiving device.

Classification of networks

local area network (LAN): is a network that connects computers and devices in a limited geographical area. Each computer or device on network is none as a node. Connected via cables. wireless LAN (WLAN): is a LAN that uses no physical cables. WLAN communicated with LAN to access its resources. metropolitan area network (MAN): is a high-speed network that connects local area networks in a metropolitan are such as a city or town and handles the bulk of communications activity across the region. wide area network (WAN): is a network that covers a large geographic are using communications channels that combines many types of media such as telephone lines, cables, and radio waves.

wireless internet access point

locations where people can connect wirelessly to the internet hot spot: a wirless network that provides internet connections to mobile computers and devices. ex: wi-fi, wimax, and Bluetooth. mobile wireless networks: provide users with high-speed wireless internet connections, as long as they are in the network's range.

client/server network

on or more computers act as a server and the other computers on the network request services from the server. Usually 10 + computers

Picture/video messaging

picture messaging: users can send pictures and sound files, as well as text messages video messaging: users can send short videos. Both called MMS (multimedia message service) mobile to mobile mobile to e-mail

Collaborate

programs working online with other users connected to a server. 3 types: collaborative software: includes tools that enable users to share documents via online meetings and communicate with other connected users. ex: online meetings: share documents in real time, web meetings. email: document management system: provides storage and management of a company's documents, such as word processing documents, presentations, and spreadsheets. ex: google docs

RFID

radio frequency identification, is a standard specifically a protocol, that defines how a network uses radio signals to communicate with a tag placed in or attached to an object, an animal, or a person. Can be passive or active.

network topology

refers to the layout of the computers and devices in a communication network. star, bus, and ring.

dial-up modem

s communications device that can convert digital signals to analog signals and analog signals to digital signals so that data can travel along an analog telephone line. usually in the form of an adapter car.

TCP/IP

short for transmission control protocol/ internet protocol, is a network standard, specifically a protocol that defines how messages are routed from one end of a network to the other, ensuring the data arrives correctly. Describes rules for dividing messages into small pieces, called packets. packet switching: breaking a message into individual packets, sending the packets along the best route available, and the reassembling the data.

Groupware

software that helps groups of people work together on projects and share information over a network. workgroup computer: includes network hardware and software that enable group members to communicate, manage projects, schedule meetings, and make group decisions.

Network card

sometimes call network interface card, is a communications device that enables a computer or device that does not have built-in networking capability to access a network. wireless network card: network cards that provide wireless data transmission also are available.

token ring

standard specifies that computers and devices on the network share or pass a special signal called a token in a unidirectional manner in a preset order. token: a special series of bits that function like a ticket. Rink topology. Physical configuration

protocol

standard that outline characteristics of how two network devices communicate

IrDA

standard to transmit wirelessly to each other via infrared light waves. line of sight transmission: the sending device and the receiving device must be in line with each other so that nothing obstructs the path of the infrared light wave.

Bandwith

the amount of data, instructions, and information that can travel over a communications channel.

Broadband

transmits multiple signals simultaneously offer on DSL and the cable television internet service. Two types: physical transmission media: use wire, cable, and other tangible materials to send communications signal. wireless transmission media: send communications signals through the air or space using radio, microwave, and infrared signals.

physical transmission media

twisted pair cable, coaxial cable, and fiber optic cable.

UWB

ultra-wide band, is a network standard that specifies how two UWB devices use short-range radio waves to communicate at high speeds with each other. UWB is best suited for transmission of large files such as video, graphics, and audio.

Wireless modem

uses the cell phone network to connect to the internet wirelessly from a notebook computer, a smart phone, or other mobile devices.

Wi-Fi

via this computers and devices have the appropriate wireless capability can communicate via radio waves with other computer or devices. 802.11: developed by IEEE, is a series of network standards that specifies how two wireless devices communicate over the air with each other. When Wi-Fi access internet works in conjunction with the TCP/IP network standard. Wi-Fi mesh network: for college campuses, each mesh node routes its data to the network available node until the data reaches its destination, usually the internet.

Types of home networks

wired home network, ethernet network, powerline cable network (network uses the same lines that bring electricity into the house), phoneline network (network that uses telephone lines in the home), wireless home networks.

WAP

wireless application protocol, is a standard, specifically a protocol, that specifies how some mobile devices such as smart phones can display the content of internet services such as the web, e-mail, and chat rooms. TCP/IP network standard, WAP uses a client/server network.

Communications discussed in the Chapter

wireless messaging services, wireless internet access points, cybercafés, global positioning systems, collaboration, groupware, voicemail, and web services

Broadcast radio

wireless transmission medium that distributes radio signals through the air over long distances such as between cities, regions, anc countries or short distances. ex: bluetooth, UWB, WiFi, an d WiMAX

WiMax

worldwide interoperability for microwave access, also known as 802.16, is a network standard developed by IEEE that specifies how wireless devices communicate over the air in a wide area. Fixed wireless and mobile wireless. Connects mobile users to the internet via hot spots.