Short lectures in Media History Chapter Seven Telephone and Telegraph .
Telecommunications and Networking. What is Telecommunications The transportation of information via...
-
Upload
lenard-davidson -
Category
Documents
-
view
219 -
download
0
Transcript of Telecommunications and Networking. What is Telecommunications The transportation of information via...
![Page 1: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/1.jpg)
Telecommunications and Networking
![Page 2: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/2.jpg)
What is Telecommunications
• The transportation of information via electronic means– Could include telephone & telegraph
• Data Communications is the part of telecommunications that relates to computer systems or the electronic transmission of data
![Page 3: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/3.jpg)
Importance of Telecommunications
• Provides the foundation for the Internet
• Dramatic cost reductions in the areas of applications development deployment
![Page 4: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/4.jpg)
Importance of Telecommunications
• Transportation of different types of data– Voice, Video, Data, Fax, etc.
• Collaboration
![Page 5: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/5.jpg)
Components of Telecommunications Systems
• Hardware and Telecommunications Software
• Communications Channels– Links required for data and voice to be
transmitted and received
• Communications Processors– Support functions for transmission and reception
• Protocols
![Page 6: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/6.jpg)
Types of Signals• Analog
– Used in everyday telephone conversations
• Digital– Electrical impulses representing a high signal (1) or a low
signal (0)
• Digital has several advantages– Lower error rates– Higher transmission speeds– Inherently less noise
• Noise is filtered out
– No conversion required
![Page 7: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/7.jpg)
Purpose of the Modem
• Modulator/Demodulator
• Converts analog to digital
• Converts digital to analog
• Handshaking or “Interfacing”– Ensures correct protocols are used
• Filters the signal to reduce errors
• Clocking– Timing the rates to sparse data correctly
![Page 8: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/8.jpg)
Communications Channels
• Twisted Pair
• Coaxial Cable
• Fiber Optic
• Microwave
• Satellite
![Page 9: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/9.jpg)
Characteristics of Communications Channels
• Buad Rate– The number of discrete signals over a period of time
• Bandwidth– Determines how much data can be pushed through
– Difference between lowest frequency and highest frequency as measured in Hertz
– Telephone lines transmit between 300hz and 3300hz• Bandwidth is 3000 hz
![Page 10: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/10.jpg)
Sources of Error• White Noise
– Gaussian Noise
– Hissing noise due to movement of electrons
• Impulse Noise– External spikes, ex. Lightning
• Crosstalk– Signals from one channel interferring with another
• Echo– The reflection or reverse of the signal transmitted
• Attenuation– Decrease in signal strength dues to distance
![Page 11: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/11.jpg)
Error Detection• Parity Checking
• Cyclical Redundancy Check
• Error Prevention– Telephone line conditioning
• Service performed by Telephone Company
– Lower transmission speeds for digital
– Shielding
![Page 12: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/12.jpg)
Media Selection Criteria
• Cost• Speed• Availability• Expandability• Error Rates• Security• Distance• Environment• Application• Maintenance
![Page 13: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/13.jpg)
Network Topologies• Star
– All are connected to a central computer– If the central node goes down, all are down
• Bus– Entire network on a single circuit– Popular in LANS– Message is sent over the network and each station is checked to see if the
addresses match• Token Ring
– Each node is sequentially checked to determine if they have a message to send– You must wait for the token before you can send your message
• You can combine networks
![Page 14: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/14.jpg)
LAN and WAN Components
• File Server– Stores programs and/or data for users to access
via a network
• Bridges– Connects similar networks together to facilitate
communications
• Gateways– Connects dissimilar networks together to
facilitate communications
![Page 15: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/15.jpg)
Protocols
• TCP/IP– Extremely popular– Used to establish connections on the Internet
• IPX– Protocol used with Novell Communications
software
• SNA– Used by many mainframes and other IBM
systems
![Page 16: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/16.jpg)
TCP/IP• Transmission Control Protocol / Internet
Protocol
• Developed for the sole purpose of communicating over large geographic areas
• Well suited to allow connectivity between dissimilar operating systems
• Standard used on the Internet since 1983
• To understand TCP/IP is to understand the Internet……. So let’s try
![Page 17: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/17.jpg)
TCP/IP
• TCP/IP Protocol Stacks– Provides standards for network
communications
• Consists of 4 layers– Network Interface Layer– Internet Layer– Transport Layer– Application Layer
![Page 18: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/18.jpg)
Network Interface Layer
• Consists of the Network Interface Card and the Network Interface Card Driver
• Responsible for putting packets on and off the wire
• Packet Switched Technologies supported:– X.25– Frame Relay– ATM
![Page 19: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/19.jpg)
Internet Layer
• Encapsulates packets into internet datagrams and runs the routing algorithms
• Controls the messages as they are sent and received
• Resolves addresses
![Page 20: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/20.jpg)
Transport Layer
• Provides communications sessions between computers
• Establishes sessions by polling destination computer’s port address
• TCP tells host computer how much data the destination computer can receive
• Establishes a connection
![Page 21: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/21.jpg)
Applications Layer
• Area where applications gain access to the network– How applications talk to the network
• Microsoft provides two API’s (Application Programming Interfaces) for use with TCP/IP– Windows Sockets– NetBios over TCP/IP
![Page 22: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/22.jpg)
IP Addresses• Looks like 223.107.2.200
• Acts as your mail address on the Internet
• Provided by a local ISP– Internet Service Provider
• 223.107.2 portion– Defines the network id
• 200– Defines the node on the network
• Subnet Addresses are used when a network has a sub-network
![Page 23: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/23.jpg)
Controlling TCP/IP
• Dynamic Host Configuration Protocol (DHCP) is a program that centrally manages the allocation of TCP/IP information
• DHCP is a server program which runs on a Windows NT Server
• DHCP must have a static IP address
![Page 24: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/24.jpg)
Network Communications• Telnet
– Remote terminal emulation protocol
– You must be known to the host and have an account on the host
• FTP– File Transfer Protocol
– Must have an account or the server allows anonymous accounts
– Program that transfers text and binary files between TCP/IP computers
![Page 25: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/25.jpg)
Network Communications
• Web Browsers– Netscape, Internet Explorer
• Access documents and multimedia files using HTTP– Hypertext Transfer Protocol
• After the data is sent the connection is closed
![Page 26: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/26.jpg)
Competitive Advantages using Telecommunications
• Groupware– Users share common databases– Able to collaborate on a variety of issues– Disparate forms of information can be
contained in a central database• Word Documents, Excel spreadsheets, Email• RDBMS’ required standardized data
– Easily facilitates mobile computing– Virtual meetings
![Page 27: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/27.jpg)
Knowledge Sharing Editorial
• Leading-edge firms create and maintain a culture which promote knowledge creation by encouraging information sharing, openness and trust, cooperation and collaboration, continual search for knowledge and truth, risk taking, experimentation, and a respect other’s knowledge and expertise
![Page 28: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/28.jpg)
Telecommunications and Teamwork
• Team– A well-defined group of individuals sharing a common
goal who must interact among themselves to perform their work
• Today’s teams must often transcend time and space
• Communication speed and convenience often make or break a team’s efforts
• Teams need the right information at the right time– Pulled rather than pushed
![Page 29: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/29.jpg)
Telecommunications and Teamwork
• Teams need to rely on repositories of information from previous experiences rather than “re-invent the wheel”
• Telecommunications provide the tools to allow teams to quickly communicate, store and share results and cross time and space boundaries to maximize efforts
![Page 30: Telecommunications and Networking. What is Telecommunications The transportation of information via electronic means –Could include telephone & telegraph.](https://reader036.fdocuments.net/reader036/viewer/2022062421/56649e4e5503460f94b44e78/html5/thumbnails/30.jpg)
Competitive Advantages using Telecommunications
• The Internet• Cost reductions through teleconferencing and
videoconferencing• Voice Mail and electronic mail
– Cost reductions– Information can be pulled when needed
• EDI– Lower cost– Lock in customers and/or suppliers