1. Chapter 6

2. Module 6A Telecommunications
Module 6B Networks
Chapter 6

3. Telecommunications Understanding the Telephone System
Modems: From Digital to Analog & Back
Digital Telephony: Living with Twisted Pair
Alternatives to Digital Telephony
Convergence: Is It a Phone or a Computer?
Module A

4. Understanding the Telephone System
Telecommunications
Understanding the Telephone System
Module A
Public switched telephone network (PSTN)
analog system based on standards that date back more than a century
Learn more about the PSTN and fast-breaking new telecommunications technologies? PhoneZone.com’s tutorials.

5. Understanding the Telephone System
Telecommunications
Understanding the Telephone System
Quality of Service (QoS)
Local Exchange Carriers (LECs)
local access & transport area (LATA)
twisted pair
local loop
Module A
Fiber Optics Online is a trade journal specializing in fiber optics industry; this is a great site to learn about new technologies.

6. Long-Distance Transmission Media
Telecommunications
Long-Distance Transmission Media
If you place a call outside the local transport area, an interchange carrier (IXC)—a long-distance telephone company—comes into play
Module A
Transmission facilities
copper wire
fiber-optic cables
microwaves
satellites
Fiber optic cables consist of thin strands of glass that transmit data by means of pulses of light.

7. Standards and Regulations
Telecommunications
Standards and Regulations
Standards
International Telecommunications Union (ITU)
Universal service
Common carrier immunity
Deregulation
Regional Bell Operating Companies (RBOCs)
Module A
The home page of Pacific Bell, a RBOC, is packed with information and tutorials about cutting-edge telecommunications services.

8. More Ways to Access the System
Telecommunications
More Ways to Access the System
Private Branch Exchange (PBX)
Cellular telephones
Leased lines
Module A
Cellular telephones enable subscribers to place calls via a wireless communications system.

9. The PSTN in Perspective
Telecommunications
The PSTN in Perspective
Module A
Sender of call
receiver of call
As a caller moves from one area to another, a new cell site steps in to keep the signal strong. The sites are connected to a Mobile Telephone Switching Office (MTSO), which is connected to the standard PSTN telephone system.

10. Modems: From Digital to Analog & Back
Telecommunications
Modems: From Digital to Analog & Back
Telephone lines use analog transmission
receiver
sender
Module A
Modem 2
Modem 1
How modems work
modulation
demodulation
internal modem
external modem
A modem transforms the computer's digital signals into analog tones that can be conveyed through the telephone system.

11. Modems: From Digital to Analog & Back
Telecommunications
Modems: From Digital to Analog & Back
Asynchronous Communication
asynchronous: used by modems
synchronous
Modulation Protocols
data transfer rate
bits per second (bps)
V.90 maximum rate of 56 Kbps
V.34 maximum rate of bps
fall back
Module A

12. Telecommunications
Fax
Module A
Facsimile transmission enables you to send an image of a document over the telephone lines to anyone who has a fax machine. If your computer has a fax modem, you can send and receive faxes from your computer.

13. Digital Telephony: Living with Twisted Pair
Telecommunications
Digital Telephony: Living with Twisted Pair
Bandwidth
measured in Kbps, Mbps, or Gbps
Last mile technologies
Integrated Services Digital Network (ISDN)
Digital Subscriber Line (DSL)
Synchronous Optical Network (SONET)
Module A
BellSouth is one of the first RBOCs to offer ADSL service. Follow the links to FastAccess to learn more.

14. Alternatives to Digital Telephony
Telecommunications
Alternatives to Digital Telephony
Direct Broadcast Satellite (DBS)
Cable Modems
coaxial cable
Electrical Power Systems
Module A
In contrast to twisted pair, it’s easy to achieve very high bandwidth data communication with coaxial cable.

15. Convergence: Is It a Phone or a Computer
Telecommunications
Convergence: Is It a Phone or a Computer
Digitization enables convergence, a process of technological “morphing” in which previously distinct devices lose their sharply-defined boundaries, and blend together.
Module A

16. Convergence: Is It a Phone or a Computer?
Telecommunications
Convergence: Is It a Phone or a Computer?
The everything PC
TV Internet set-tops
Personal Communication Service (PCS)
Internet telephony
Internet faxing
Module A
WebTV allows you to access the Internet using your television set as a display. Visit their web site for more information.

17. Networks Introducing Computer Networks Network Fundamentals
Local Area Networks (LANs)
Wide Area Networks (WANs)
Module B

18. Introducing Computer Networks: Synergy at Work
What is a computer network?
Types of computer networks: LANs & WANs
local area network
metropolitan area network
wide area network
Networking synergies in a nutshell
reducing hardware costs
enabling shared applications
building massive information resources
connecting people
Module B

19. Introducing Computer Networks: Synergy at Work
Module B
Computer networks enable users to share software and to create common pools of data.

20. Network Fundamentals Physical media Switching & routing techniques
Networks
Network Fundamentals
Physical media
Switching & routing techniques
circuit switching
packet switching
which is best
Module B

21. Network Fundamentals Protocols Network layers proprietary protocols
Networks
Network Fundamentals
Protocols
proprietary protocols
open protocols
protocol suite
Network layers
the protocol stack
Module B
stack
protocol
layers
A message starts at the "top" of a stack of layers and moves down through the various layers (protocol stack) until it reaches the "bottom" or physical media.

22. Local Area Networks (LANs): Limited Reach, Fast Connections
Keyboard & monitor for server
Module B
Computer 3
Personnel
Computer 4
Server - Daily sales
Computer 2
Accounting
Computer 1
Sales & marketing
Laser
printer
LANs transform an organization's hardware into what seems to users like one gigantic computer system.

23. Local Area Networks (LANs): Limited Reach, Fast Connections
Networking hardware: Network Interface Cards (NICs)
workstation
node
Networking software
peer-to-peer networks
client/server networks
Clients
Module B

24. Local Area Networks (LANs): Limited Reach, Fast Connections
Media
twisted pair
coaxial cable
fiber-optic cable
infrared
radio
LAN topologies
bus (daisy chain)
star
ring
Module B

25. Local Area Networks (LANs): Limited Reach, Fast Connections
Module B
Most networks use a bus, star, or ring topology.

26. By far the most popular LAN standard is Ethernet
Networks
LAN Technologies
Module B
By far the most popular LAN standard is Ethernet
Like to know the latest news about LANs? Check out LAN Times, the premiere LAN trade journal
Like to learn more about the Ethernet? Check out Charles Spurgeon’s Ethernet Web Site which covers all the Ethernet technologies used today and includes a practical guide for do-it-yourselfers.

27. LAN Protocals AppleTalk IPX/SPX NetBEUI TCP/IP B
Networks
LAN Protocals
AppleTalk
IPX/SPX
NetBEUI
TCP/IP
Module B
Like AppleTalk, TCP/IP can be used with a variety of lower- level protocols, such as Ethernet. A LAN that uses TCP/IP is called an intranet, a term that suggests that it’s an Internet designed for internal use within an organization.

28. Wide Area Networks (WANs): Long-Haul Carriers
WANs are like long-distance telephone systems
Module
How WANs work
Point of Presence (POP)
backbones B
The Internet is a WAN of massive proportions. Backbone provider UUNET offers local access from more than 1,000 locations worldwide.

29. Wide Area Networks (WANs): Long-Haul Carriers
How WANs are organized
public data network (PDN)
virtual private network (VPN)
WAN protocals
oldest is X.25
WAN Applications
LAN-LAN connections
transaction acquisition
electronic data interchange (EDI)
Module B
To explore cutting-edge WAN technologies such as SDMS and ATM, a good place to start is Pacific Bell’s FasTrak Data and Video Services page