Basics of Telecom

8/6/2019 Basics of Telecom

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Objectives

At the end of this session you will be able to:

Explain the history of Telecom

Explain Analog and Digital Signals

Explain Switching

Explain PSTN Explain Network Units and Bandwidth

List the commonly used terms in Telecom

Explain the various transmission media

Explain some Reliance Communication Telecom concepts


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Evolution of Communication It started from cave drawings

& it keeps evolving

Cave

Drawings

Smoke

SignalsSignals by

beating

Drums Telling

Stories

Cuneiform

Writing Telegraphs

Telephones

- Wire line

To Wireless


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Advent of the Telephone

Alexander G Bell testing an old prototype of

the phoneAntonio Meucci


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A Telecom Network in Action

Source : www.howstuffworks.com


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ANALOG =

Analog Signals

Think waves


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DIGITAL =

Digital Signals

1 1 1 1 10 0 0 0

Time


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Analog Vs. Digital

Telephone Networks need to support both types of signals!

How is it done?

VoiceAnalog

Data

00100011101110100111010 Digital


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Exercise Analog Vs Digital Signal


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Computerand Communication

DIGITAL =

ANALOG =

Telephone Telephone

Computer

Modem

Computer

Modem


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Modem

A modem is apiece of hardware that allows your computer to talk to other

devices over regularphone line

A modem converts digital signals from your computer into audible tones that

can be transmitted over regularanalog phone lines

This conversion process is called MOdulation The modem on the other end then transfers those same audible tones back

(orDEModulates) into their original digital signals

Modulation and Demodulation is where the word Modem comes from


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Working of Modem


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Bits & Bytes

The unit of DigitalInformation is a Bit

A bit may be a 0 ora 1

A byte is8 bits put together

1 1 0 0 0 1 0 1

A Byte

Bit


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A Bigger Bit

Bit

Byte

Kilobit

(Kb)

egabit

( b)

Gigabit(Gb)

8 Bits 1 Byte

103 Bits 1 kbit

103 kbit 1 Mbit

103 Mbit 1 Gbit


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Bandwidth

Bandwidth is the rate at which data is transferred

Bits of data transferred per second

Its units are Kilobits/sec (Kbps) and Megabits/second (Mbps)


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Kbps

Mbps

Gbps 1,000,000,000x

Bandwidth (contd)

In telecommunications, bandwidth

refers to carrying capacity

For digital signals, bandwidth is

measured in Kilo bits per second

(kbps), Mega bps, Giga bps, etc.

Just as more water fits into a wider

pipe and hence moves faster,

medium having more bandwidth

moves data faster

1,000,000x

1,000x


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Voice, Dataand Video Bandwidth Needs

Voice

- Typicallocalphone line operates at 64 kbps (64,000 bits/second)

Data

- Most modems run at 28.8 kbps

- Typical data services range from 56 kbps to 45 Mb/s- New fiber optic electronics now allow multiple channels of 10 GB/s to be

transmitted overa single fiber

Video

- Full-motion broadcast-quality video requires approximately VCR-quality video

~ 1.5 Mb/s

- Video conferencing can be done at 384 kbps


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Bandwidth in Perspective

Estimated time to transmit a two-hour, fully-digitized movieover various bandwidths:

21 hrs

3.5 days

2 seconds

Modem at 14.4 kbps

Data line at 1.5 mbps

ISDN line at 64 kbps

Cable line at 10 mbps

Optical fiber at 2.5 gbps

53 min.

8 min.


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Switching

Problem: If we were to have direct lines to every place

users wanted to call, it would require wires from every

phone to every place they wanted to call!

Switch

Solution: Switching!


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Switching

Manual Switching Electronic Switching

A Switch allows a connection to be established,

as necessary and terminated when the

communication session is over.


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Public Switched Telephone Network (PSTN)

The public telephone

network in India (like most

countries) is comprised of

all of the existing telecom

infrastructure, mostly

developed by the

government or

monopolies. It is primarily

an analog system made

up of copper wire.


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Transmission Facilities

Transmission Facility

- Provide the communication paths that carry userand network control

information between nodes in a network.

- In general, transmission facilities consist ofa medium (wire or the

atmosphere) and various type of electronic equipment located at points along

the medium.

Transmission

Facilities

Transmission

Facilities

Network


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Transmission Medium

Fiber

Co-axial

Microwave orwireless

Satellite

Copper

(twisted wire)


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Optical NetworksThese are networks created using the optical fibre, which supports

transmission in the form of light pulses


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Advantages of Optical Network

Cables are smaller in size and lighter

Use light pulses in place of electric pulses, they are not subject to noise and

error

Prevent fire hazards as they transmit data in the form oflight pulses

Reduce the loss of information while transmission and so do not require asmany boosting devices

Offerlarger bandwidths

Lesser joints/seamless, therefore delivers better quality

Is not affected by water,air sunshine-therefore breakdown in monsoons is

unheard of

It is tapproof, therefore helps in controlling cost


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Telecommunications

Telecommunications is the science of communicating overlong distance

using telephone or radio technology

This involves using computerand PC technologies to transmit, receive and

switch voice, dataand video communications over different transmission

media, including copper, fibre etc.


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Telephony

Telephony is the traditional voice communication overa wired/wireless

network

It is communication facilitated by the telephones


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Some Commonly Used Terms

TDM

GSM

CDMA

Activation

Deactivation

Dial Tone

Voice Mail

Network

3G

Transmission WAP

GPRS

MMS

SMS

I/C

O/G

Tariff Roaming

Inter-Circle

Intra-Circle

SIM

Monthly Charges Prepaid

Postpaid

PSTN

BTS

BSC

HLR

VLR

MSC

ARPU

TRAI


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Circle Definition

Management Circles

- Circles that are integrated together for management purposes and better

administration

Telecom Defined Circle OR BSNL Circles

- Circles defined by DOT (Department of Tele Communications) as per telecom

licenses applicable to Telecom Service Providers


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Types of Circles

Inter Circle

Intra Circle

Paired Circle


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Inter Circle

A call made from Mumbai To Delhi

- Its an inter-circle callas Mumbai & Delhi are 2 different telecom circles

- Example: Radha calls her friend Suresh in Mumbai from Delhi,then it is an

out going call to Radhaand an inter circle call .This is because the origin of

the call is Delhi and the destination is Mumbai , which is in another circle. For

Suresh it is an Incoming call.

DelhiMumbai


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Intra Circle

A call made from Nagpur to Kolhapur

- Its an intra circle callas both the cities are part of same circle i.e.,

Maharashtra

- Example:Rakesh is in Nagpurand calls up his friend Mahesh who is in

Kohlapur.

- It is an outgoing call but within the same circle as both the cities are part of

the same circle Maharashtra. It is an incoming call for Mahesh

Kolhapur

Nagpur

Maharashtra

Circle


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Paired Circle

A call made from Chennai to Madurai

- Its apaired-circle callas Chennai lies within Tamil Nadu,and both are

separate circles

- E.g. Mumbai & Maharashtra, Kolkatta & West Bengal

Madurai

Chennai

Tamil Nadu


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Type of Connection

Prepaid

Postpaid

Pay before Use

Ability to control / monitor expenses

Less documentation

Instant activation

Ea

sya

va

ila

bility


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Type of Connection

Pay afterUse

Lower tariffs available

Monthly billing pattern ease of operation

No worry on talk time expiry / validity expiry

Prepaid

Postpaid


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Elements of Prepaid Tariff

Startuppack / Recharge Coupon

MRP Maximum retailprice

Activation charge (Start-Up) / Administration Fee (Recharge)

Pulse Unit to measure call duration 30sec/120sec/60sec = one call

Talk time Validity Period

Grace Period

- After the expiry of the validity period, the connection still remains foraperiod

known as Grace period

-It allows a customer to make all non billable transition (

Incoming calls, SMS)till the grace period is over or till the connection is recharged


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Elements of Post Paid Tariff

Security Deposit

Activation Fee

Monthly Commitment

Pulse

Monthly Rental


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Types of Call

On-net

- Calls made to Reliance Network are termed as On-net

Off-net

- Calls made to any other Network is termed as Off-net

- E.g. Calls from Reliance to Airtel Local

- Calls made within the city

E.g Calls within Mumbai, Nasik, Patna

International

- Calls made to other countriesE.g. Mumbai to London (England)


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Summary of Learning

By the end of the session you are able to:

State the advent of the telephone

State the difference between Analog and Digital Signals

Outline what is Switching

State what is PSTN

State and explain what are the various Network Units and Bandwidth

List the commonly used terms in Telecom

State and Explain the various transmission media

State Reliance Communication Telecom concepts


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Basics of Telecom

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