Convergence Technology

www.convergencetechnologycenter.org DUE 402356

Convergence Technology

MODULE 2 - LEARNING OUTCOME 5Describe signaling and its importance to telecommunications and differentiate various signaling techniques involved in telephony.

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What Makes the Telephone Work?• The hook switch• The Microphone• The Speaker• ECHO

Voice Telephony Fundamentals


Anatomy of the phone

Hook Switch

Microphone

Speaker

To Wall Jack


Microphone

Speaker

Duplex Coil

To Wall Jack

Touchtone Keypad

Ringer

Hook Switch

Telephone components with duplex coil and touch-tone keypad


Component Configuration

300 Ohm

9 Volt

Green wire

Red wire

Battery

Resistor


Telephone Carbon Microphone

Electric Contact

Electric Contact

Carbon Granules

Vibrating Diaphragm

Wires


Diaphragm

Voice coil

Magnet

SuspensionDust cap

-

+

How a speaker works


Wires and Cables • Residential Cabling• The Telephone Network cabling

Signaling and Transmission• Analog Signals• Digital Signals



Dual tone dialing pad


Entrance bridge

Ground wire

From the Central Office

To phones inside house

Entrance Bridge


Roadside wiring concentrator

Typical phone company boxe (wiring concentrator) that you have seen by the side of the road


Residential cabling

Residences


WaveformSine Wave Anatomy

FrequencyWavelength

AmplitudeSignal Phase



Electromagnetic wave form


Anatomy of a sine wave

2700180090000

One SecondOne cycle

3600

V = Voltaget = time A = Amplitude

One cycle per second = one Hertz

a

a

One Hertz

t


Cycles per second

2 cycles per second (2 Hz)

1 cycle per second (1 Hz)

4 cycles per second (4 Hz)

One Second


Phase Shift


Analog signal being digitized


Digital Signal types

Unipolar

Manchester

Bipolar Return to Zero

Bipolar Nonreturn to Zero

Differential Manchester


The Codec

Analog Phone

Analog Phone

Digital Transmission (Digital Data Lines

Codec

Analog Signal

Digital Signal


Analog to Digital to Analog

Central office

A/D conversion

Central Office

D/A conversion

Dallas Boston


Local and Long-Distance Calling• The Protocol for Making a Phone Call• DTMF (Dual-Tone MultiFrequency)



Dual tone dialing pad


Transmission Lines• Attaching Transport Devices• Circuits

• Two-Wire Circuits• Four-Wire Circuits• The Effects of Attenuation When

Using Two-Wire or Four-Wire



Analog to Digital to Analog

Central office

A/D conversion

Central Office

D/A conversion

Dallas Boston


Two-wire and four-wire pairs

Four wire – two pair

Outer Jacket

Braided shield

Foil shield

Twisted Pairs

Eight wire - four pair

Twisted Pair

Plastic insulation

Outer Jacket


Two-wire circuit as used in the Local Loop


Four-wire circuit

Customer Site Carrier

Transmit

Transmit

Receive

Receive


•Lines and Trunks•CPE Switches

•Network Switches•Channels

•Virtual Circuits•Flavors of Virtual Circuits•Network Connections



CPE lines, trunks, switches

Core NetworkClass 4 Switches

Interexchange Trunks

Class 5 Switches

Subscriber Lines

Local Exchange TrunksLocal Loop

PBX

Business Phones

CPE

International Gateway

PBX

Residential Phones


Bandwidth• Getting more out of a wire pair• Bandwidth and the Electromagnetic

Spectrum• Electromagnetic Spectrum



Electromagnetic Spectrum


The anatomy of an analog voice channel

Frequency multiplexed voice signalsBandwidth of a voice channel


Questions: Feel free to contact the creator of this material Peter Brierley, Professor, Collin County

Community College, [email protected]

This material is based upon work supported by the National Science Foundation underGrant No. 0402356. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation

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