Telecommunications: transmittal of data and information
Allows communications over large distances
Network technologies bring about several improvements to business process
Advantages of telecommunications
Better business communication
Geographical distance irrelevant
Greater efficiency
Information becomes immediately available
Better distribution of data
Advantages of telecommunications
Instant transactions
Flexible and mobile workforce
Alternative channels
Network security is risk
Name derived from areas of service called cells
Use computerized transceiver
Transmits and receives signals
Transmit and receive calls almost anywhere
Other uses
E-mail and faxing
GPS
Digital cameras
Major advantage is mobility
Videoconferencing: transmitted images and speech
Brings conference rooms thousands of miles apart together
Save on multiple costs
Travel
Lodging
Time
Fax: Transmission and reception of images over telephone line
Fax machine digitizes image and transmits representative bits to other fax machine
Can be sent through Internet
Uses special software
Radio frequency identification (RFID) technology enables quick transactions and payments
Used in gas stations and wireless toll plazas
Facilitates payments
Used in warehouses
Check availability
Locate items to be picked up and stored
Peer-to-Peer file sharing: locate and download files from online computer through Internet
LimeWire
KaZaa
Morpheus
Exchange music and video files
Raises many issues with copyright violation
BitTorrent: Download segments of files from multiple sources
Increasingly fast communication allows businesses options
Research
Market
Educate
Train
Shop
Entire industries created by Web
Online exchanges and auctions
Bandwidth: speed at which data are communicated
Bits per second: unit of measure for bandwidth
Baseband: carry only one transmission at a time
Broadband: carry multiple transmissions simultaneously
Several types of communications media
Tangible or intangible
Tangible
Twisted pair cable
Coaxial cable
Optical fiber
Intangible media
Microwave radio technologies
Twisted pair cable: pairs of insulated copper wires twisted together
Twisting reduces electromagnetic interference
Low cost
Used in networking devices
Coaxial cable: for cable television transmission
Used for Internet
Optical fiber: uses light to represent bits
Not susceptible to interference
Microwaves: high-frequency radio waves that can carry signals over long distances
Used in radio-frequency technologies
Signals transmitted by satellite links
Geostationary satellites are farther away from the Earth
Electrical power lines: electrical power grid used for telecommunication
Network: combination of devices (nodes) connected through communication channels
Any compatible device can transmit and receive on a network
Three basic types of networks
Local area network (LAN): established by single organization and shared among employees
Server: single computer often used as central repository of programs and files for all computers
Peer-to-peer LAN: no central device controls communications
Wireless LANs (WLANs): easier installation and more scalable
Scalability: ease of expanding system
Wireless networks less secure
Metropolitan area network (MAN): links multiple LANs within large city
Wide area network (WAN): far-reaching system of networks composed of LANs or MANs
Value-added networks (VANs): networks with enhanced services
Reliability
Management
Maintenance
Internet service providers (ISPs): preferred method of conducting commerce
Personal area network (PAN): wireless network designed for handheld and portable devices
Used by one or two people
Transmission speed slower
Maximum distance 10 meters
Networks use variety of devices to connect computers and peripheral devices
Network interface card: connects through cable or wireless antenna to middle device
Middle device connects to LAN or WAN
Hub: central location to connect computers
Switch: controls direction of communications
Bridge: connects two networks
Router: routes data packets to next node
Repeater: amplifies or regenerates signals
Modem: translates communication signals form analog to digital and vice versa
Dial-up connection: slower type of connection through modem
Virtual private network (VPN): alternative to creating LAN
Does not require leasing of lines
Utilizes Internet, a public network to simulate a private network
Enables intranets and extranets
Circuit switching: dedicated channel established for duration of transmission
Packet switching: message broken into packets
Packet: group of bits transmitted together
Frame relay: high-speed packet-switching protocol used in WANs
Variable-sized packets routed quickly
Protocol: set of rules governing communication between computers
Protocol is like human language and basic understanding
Some protocols designed for WANs, LANs, and wireless communications
Most important set of protocols called TCP/IP
TCP/IP: Transmission Control Protocol/Internet Protocol
Ensures packets arrive accurately
Ensures delivery of packets from node to node, respectively
Internet backbone: highest speed channels
Host: computer connect directly to backbone
IP number: unique identification for device
DNS: Domain Name Service maintains character-based names of IP numbers
Static IP number: permanent number assigned to device
Dynamic IP number: temporary IP number assigned for duration of connection
Ethernet: LAN protocol using coaxial cable
Gigabit Ethernet: faster Ethernet connections
Devices on network contend with other devices for transmission time
CSMA/CD protocol ensures no collisions in transmission
IEEE 802.11: known as Wi-Fi
Supports wireless communication within 100 meters of router
Max speed 11 Mbps
Access point (hotspot): allows Internet access within range of equipment
Encryption: ability to scramble and code messages
Use keys shared between sender and receiver
Bluetooth: allows devices to communicate within 10 meters
Worldwide Interoperability for Microwave Access (WIMAX): increases range and speed of wireless communication
Works with metropolitan area networks
Mobile Broadband Wireless Access (MBWA): similar to cell phone communications
Compatible with IP services
Compatible with Wi-Fi and Bluetooth
Networking professionals refer to generations of mobile communication technologies
First generation analog
Second generation used digital voice encoding
Third generation stepped up speeds
Fourth Generation digital
Packet switching
Higher security
Variety of options to choose from when subscribing to network services
Downstream: speed of receiving from network
Upstream: speed of
Internet links provided by television cable firms
Cable connected to Internet server
At residence, cable split into TV set and computer
Cable shared by all subscribers
Digital subscriber line (DSL): data remains digital through entire transmission
Uses telephone lines connected to DSL bridge
Several types of DSL
Asymmetric allows different upstream and downstream rates
Transmission rates closely related to distance from telephone company
T1 and T3 lines: point-to-point dedicated digital circuits
T3 lines made of 24 channels of 64 Kbps
T1 line made of 672 channels of 64 Kbps
Expensive
Used in universities
Satellite services use microwaves
Service provider installs dish antenna, used as communications satellite
Speeds up to 45 Mbps
GPS free satellite service
Fixed wireless: point-to-point transmission between two stationary devices
Wireless Internet service provider (WISP)
Provides fixed wireless service
Highly modular and scalable
Optical carrier
Expensive
High connection speeds
Uses basic unit of 51.84 Mbps
Used by
ISPs
Search engines
Content-rich Web sites
Broadband over Power Lines (BPL): uses electric power lines to carry digital signals
Used by utility companies
Monitor power consumption
Detect power failure
Track power outages
Voice over Internet Protocol: uses Internet connection to conduct telephone conversations
Free of charge
Different quality of sound from traditional telephone services
Does not allow calls to emergency numbers such as 911
RFID tags tiny and need little power
Objects are embedded with tags that contain radio transceiver
Tags encoded with electronic product code
Readers decode data stored in tag’s memory and data passed to host computer
Convergence occurs in networking technology
Cell phones can act as Web phones
Television sets connect to Internet
Wireless technologies combined in same device enhance functionality
Telecommunications is communication over distance
Different media have different bandwidths
Networks are classified according to reach and complexity
Network can be turned into a virtual private network (VPN)
Two ways to switch a communication line: packet switching and circuit switching
Network protocols are sets of rules to which all devices on network must adhere
The Internet adheres to the TCP/IP protocol
Wireless technologies make it easy and affordable to create wireless LANs
Organizations and individuals have variety of choices when subscribing to networking services
As Internet links become faster, Internet telephoning is gaining in popularity
Wireless technologies support the increasingly popular RFID technologies
Much like hardware, telecommunications technologies are merging
Increasing numbers of employees now telecommute
