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Convergence Technology. MODULE 2 - LEARNING OUTCOME 5 Describe signaling and its importance to telecommunications and differentiate various signaling techniques involved in telephony. Voice Telephony Fundamentals. What Makes the Telephone Work? The hook switch The Microphone The Speaker - PowerPoint PPT Presentation
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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
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Anatomy of the phone
Hook Switch
Microphone
Speaker
To Wall Jack
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Microphone
Speaker
Duplex Coil
To Wall Jack
Touchtone Keypad
Ringer
Hook Switch
Telephone components with duplex coil and touch-tone keypad
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Component Configuration
300 Ohm
9 Volt
Green wire
Red wire
Battery
Resistor
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Telephone Carbon Microphone
Electric Contact
Electric Contact
Carbon Granules
Vibrating Diaphragm
Wires
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Diaphragm
Voice coil
Magnet
SuspensionDust cap
-
+
How a speaker works
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Wires and Cables • Residential Cabling• The Telephone Network cabling
Signaling and Transmission• Analog Signals• Digital Signals
Voice Telephony Fundamentals
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Dual tone dialing pad
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Entrance bridge
Ground wire
From the Central Office
To phones inside house
Entrance Bridge
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Roadside wiring concentrator
Typical phone company boxe (wiring concentrator) that you have seen by the side of the road
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Residential cabling
Residences
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WaveformSine Wave Anatomy
FrequencyWavelength
AmplitudeSignal Phase
Voice Telephony Fundamentals
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Electromagnetic wave form
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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
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Cycles per second
2 cycles per second (2 Hz)
1 cycle per second (1 Hz)
4 cycles per second (4 Hz)
One Second
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Phase Shift
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Analog signal being digitized
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Digital Signal types
Unipolar
Manchester
Bipolar Return to Zero
Bipolar Nonreturn to Zero
Differential Manchester
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The Codec
Analog Phone
Analog Phone
Digital Transmission (Digital Data Lines
Codec
Analog Signal
Digital Signal
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Analog to Digital to Analog
Central office
A/D conversion
Central Office
D/A conversion
Dallas Boston
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Local and Long-Distance Calling• The Protocol for Making a Phone Call• DTMF (Dual-Tone MultiFrequency)
Voice Telephony Fundamentals
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Dual tone dialing pad
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Transmission Lines• Attaching Transport Devices• Circuits
• Two-Wire Circuits• Four-Wire Circuits• The Effects of Attenuation When
Using Two-Wire or Four-Wire
Voice Telephony Fundamentals
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Analog to Digital to Analog
Central office
A/D conversion
Central Office
D/A conversion
Dallas Boston
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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
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Two-wire circuit as used in the Local Loop
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Four-wire circuit
Customer Site Carrier
Transmit
Transmit
Receive
Receive
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•Lines and Trunks•CPE Switches
•Network Switches•Channels
•Virtual Circuits•Flavors of Virtual Circuits•Network Connections
Voice Telephony Fundamentals
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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
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Bandwidth• Getting more out of a wire pair• Bandwidth and the Electromagnetic
Spectrum• Electromagnetic Spectrum
Voice Telephony Fundamentals
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Electromagnetic Spectrum
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The anatomy of an analog voice channel
Frequency multiplexed voice signalsBandwidth of a voice channel
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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