3. TELECOMMUNICATIONS = Communication by electronic means/ digital data transmission like video and audio.
Technologies in Telecommunications...
Components…
- Computers.
- Terminals/data input and output
device.
- Communications processors.
- Communications software.
Functions…
- Transmit data.
- Establish interface between sender and receiver.
- Route messages.
- Process elementary info.
- Editorial tasks on data.
- Convert message speed and format.
- Control flow of info.
4. Types of Signals
Analogue:
- Continuous waveform.
- Through medium.
- Video, audio.
Digital:
- Discrete.
- 1-bits/0-bits.
- Data Communications.
Appropriate Telecommunications Media...
Channels
- Wired (twisted wire; telephone, Coaxial
cable; TV, fiber optics and optical.
- Wireless (microwages, satellites etc.
-
Modems
Translates digital into analogue and vice versa.
Processors
- Front end processor: for host computer.
- Concentrator: collects and stores messages.
- Controller: supervises traffic.
- Multiplexer: enables single channel.
5. Designing a network...
Network Topologies
Star Network: connection to
central host computer.
Bus Network: number of
computers linked by single
circuit.
Ring network: linked by closed
loop.
LANs and WANs
Local Area Networks:
- Require own channels.
- Limited distance
- Gateway, router , NOS.
WANs:
- Large distance.
- Cble, satellite and microwave
tech.
- Switched and dedicated lines..
6. Alternative Network Services
Wireless LANs (WLANs)...
- WiFi standard.
- Bluetooth standard.
Value-Added Networks…
- Private, multipath, data only, third party managed network.
Other…
- Packet switching, Frame Relay, Asynchronous Transfer Mode (ATM).
- Integrated Services Digital subscriber line (ISDN), Digital subscriber line (DSL), Cable
modems, T1 line-broadband.
7. Ecommerce and Business...
E-mail
Eliminates telephone tag and
expensive long-distance
charges.
Groupware
Allows groups at different
locations to participate in
forums, shared docs and
projects.
Voicemail
Digitises spoken message
and transmits it over
networks,
Fax
Digitises and transmits
documents over telephone
lines.
Conferencing
Teleconferencing: confer
with a group of people.
Data conferencing: Modify
data files simultaneously.
Videoconferencing: Video
call.
Learning
Distance learning: education
or training over distance.
E-learning: Instruction
delivered over internet or
private networks.
8. New Information Technology...
Enterprise Networking: arrangement of hardware, software, network and data resources, creates a
company-wide network.
Internetworking: links separate networks into an interconnected network.
Connectivity: measures how well computers and computer-based devices communicate.
Open system: software systems, operate on different hardware platforms.
Open Systems Interconnect (OSI)
Determines multiple-layer layout
to interconnect different
equipments.
TCP/IP Model
Based on OSI layers but focused
more on transmission. It is a short
practical model.
9. The Internet...
Internet Service
Provider (ISP)
Commercial organisation
with a permanent connection
to the internet.
Sells temporary connections
to subscribers.
Information
Appliance
Device customised to
perform few specialised
computing tasks with
minimal user effort.
Domain Name
System (DNS)
Hierarchical distributed
naming system for
computers, services.
Associates various
information with domain
names making them
meaningful to humans.
E-Mail
Connects people worldwide.
Creates productivity gain.
Usenet
Newsgroup
Online discussion groups
using electronic bulletin
boards.
Additional
Communication
Tools
LISTSERV, Chatting, Instant
messaging, Internet
telephony (VolP)., Telnet,
File Transfer Protocol (FTP).
10. WWW/ Web Tech and Wireless Web...
Main Features…
- Based on HTML.
- Combines text, hypermedia, graphics and sound.
- All types of digital communications.
- Uses graphical user interfaces for easy viewing.
Search engine - locates specific sites or information on www and FTP.
Shopping Bot - software with level of intelligence, helps e-commerce shoppers locate products and services.
Push tech - information broadcast directly to user based on pre-specified interests.
Multicasting - transmission of data to a selected group of recipients.
Firewall - hardware or software places between an internal and external network.
Extranets - private intranets extended to authorised users outside company.
11. Tech for E-commerce and Business...
Hit…
- Entry into Web server´s log file.
- Generated by each request to the server for a file.
Electronic commerce server software…
- Provides functions essential for running e-commerce web sites.
Customer tracking and personalisation…
- Collecting and storing data.
- Combining data with stored data.
- Analysing data.
- Identifying customer preferences.
12. Management Problems due to IT
- Loss of management control.
- Connectivity and application challenges.
- Organisational change requirements.
- Hidden costs of enterprise computing.
- Scalability, reliability and security downtime.