Telecommunications and
Networks
Chapter 6
Principles and Learning Objectives
• Effective communication is essential to
organizational success.
– Define the terms communication and
telecommunications and describe the components of
a telecommunications system.
Principles and Learning Objectives
• An unmistakable trend of communications technology
is that more people are able to send and receive all
forms of information over greater distances at a faster
rate.
– Identify three basic types of communications media and
discuss the basic characteristics of each.
– Identify several types of telecommunications hardware
devices and discuss the role that each plays.
– Identify the benefits associated with a telecommunications
network.
– Name three distributed processing alternatives and discuss
their basic features.
– Define the term network topology and identify five
alternatives.
Principles and Learning Objectives
• The effective use of telecommunications and
networks can turn a company into an agile,
powerful, and creative organization, giving it a
long-term competitive advantage.
– Identify and briefly discuss several
telecommunications applications.
Overview of
Telecommunications Systems
Communications
Communications
Telecommunications
Telecommunications Media
Basic Communications Channel
Characteristics
• Simplex channel
• Half-duplex
• Full-duplex channel
Bandwidth
• The range of frequencies that an
electronic signal occupies on a given
transmission medium.
Broadband
• Telecommunications in which a wide band
of frequencies is available to transmit
information, allowing more information to
be transmitted in a given amount of time.
Shannon’s Fundamental Law of
Information Theory
• The information carrying capacity of a channel is
directly proportional to its bandwidth - the
broader the bandwidth, the more information
that can be carried.
Types of Media
•
•
•
•
Twisted-Pair
Coaxial Cable
Fiber-Optic Cable
Microwave Transmission/satellite
Twisted-Pair Wire Cable
Coaxial Cable
Fiber Optic Cable
Microwave Transmission
Satellite Transmission
Cellular Transmission
• Infrared transmission
– Requires line of sight
– Used in lan
– To connect to a printer
Telecommunications
Devices
Devices
• Modems:
– Analog
– Digital
• Special-purpose modems
• Multiplexers
• Front-end processors
Modems
Multiplexers
Front-End Processors
Carriers and Services
Carriers and Services
• Common carriers: long distance telco,
• Value-added carriers: these cos own pvt networks offer
services for a fee
• Switched and dedicated/leased lines:
• Private branch exchange (PBX)
• Wide-area telecommunications service (WATS): for
800/888 number, its cheaper than other billing method
• Phone and dialing services
• Digital subscriber line (DSL): 500 kbps plus speed, can
use telephone and computer at same time,need a
special modem
• ISDN: simultaneously transmit video, data, voice etc in
digital form
• T1 Carrier: 1.5 mbps speed
Integrated Services Digital
Network (ISDN)
Carriers and Services
Networks & Distributed
Processing
Basic Processing Strategies
• Centralized processing
• Decentralized processing
• Distributed processing
Network Concepts and
Considerations
• Network topology
–
–
–
–
–
Ring network
Bus network
Hierarchical
Star network
Hybrid network
• Network types
–
–
–
–
Local Area Networks
Wide Area Networks
International networks
Home and small business networks
Network Topology
Network Topology
Network Topology
Local Area Networks
Wide Area Networks
Home and Small Business Networks
Terminal-to-Host
Application and database reside on the host
File Server
Application and database reside on the file server. Dbms runs on the end
users workstation. The data is manipulated on the users station. File server
often sends the entire file not just the requested data. So it creates lot of
traffic on the network.
Client/Server
The server gets the request from the client. Sends a
message to the database server which extracts the
data, formats and sends it to the client. Here it doesn’t
send the entire file but just the data needed. So far
less traffic on the network.
Communications Software and
Protocols
Communications Software
• Network operating systems (NOS)
• Network management software
Communications Protocols
• Open Systems Interconnection (OSI) model
• Transmission Control Protocol/Internet Protocol
(TCP/IP)
• Systems Network Architecture (SNA)
• Ethernet
• Asynchronous Transfer Mode (TM)
• Bluetooth
Open Systems Interconnection (OSI)
Model
Open Systems Interconnection (OSI)
Model
Network Interconnectivity
Technology
Bridge, Routers, and Gateways
Telecommunications and
Applications
Telecommunications and
Applications
•
•
•
•
•
Voice mail
Electronic software distribution
Telecommuting
Videoconferencing
Electronic data interchange (EDI)
Videoconferencing
Electronic Data Interchange (EDI)
Public Network Services
Summary
• Communications - any process that permits
information to pass from a sender to one or more
receivers
• Telecommunications media - twisted-pair wire
cable, coaxial cable, and fiber-optic cable
• Modems - convert signals from digital to analog for
transmission, then back to digital
• Ethernet - the most widely installed local area
network (LAN) technology