Lesson 1 Sound and Telephony
Chapter 1. Sound
Nature of Sound.
Figure 1. Generation of Sounds
Transmission of Sound.
Figure 2. Sound Wave Produced by Vibrating Blade
Representation of Sound Waves.
Figure 3. Waveform of Simple Sound
Velocity and Wavelength.
Wavelength-cont.
Complex Sounds.
Voice Sounds.
Characteristics of Sound.
Characteristics of Speech.
Frequency Range of Voice Sounds.
Sound Power.
Hearing.
Face-to-Face Conversation.
Conversation by Telephone.
Summary-cont. - SS03300024
Summary-cont. - SS03300025
Chapter 2. Transmitters and Receivers
Telephone Transmitter.
Telephone transmitters.
Carbon Transmitter.
Operating principle of carbon transmitter-cont.
Application of operating principle to carbon transmitter.
Structure of Carbon Transmitter.
Figure 11. Carbon Transmitter
Figure 12. Modern Transmitter
Noise-Canceling Transmitter.
Telephone Receivers.
Magnet-Diaphragm Receiver.
Figure 15. Operation of Magnetic Diaphragm Receiver
Operating principle of magnetic-diaphragm receiver-cont.
Figure 16. Waveforms in Simple Telephone System
Structure of Modern Receiver.
Figure 17. Action of Soft Iron-ore Electron Agent on Diaphragm
An acoustical network couples
Figure 18. Telephone Receivers
Circuit Diagrams.
Types of circuit diagrams
Figure 20a. Handset, Disassembled
Reading of Schematic Diagrams.
Figure 21. Types of Circuit Diagrams
Telephone Symbols.
Summary - SS03300051
Summary-cont. - SS03300052
Figure 1-1. The sine wave.
Lesson 1 Exercises-cont. - SS03300054
Lesson 1 Exercises-cont. - SS03300055
Lesson 1 Exercises-cont. - SS03300056
Lesson 1 Exercises-cont. - SS03300057
Lesson 1 Exercises-cont. - SS03300058
Lesson 2: Telephone Systems
Chapter 3. Introduction to Telephone Systems
Figure 23. Simple telephone circuit.
Telephone Switchboard.
Telephone Central Office.
Telephone System.
Figure 27. Telephone Exchanges Connected by Trunks
Summary-cont. - SS03300066
Chapter 4. Local-Battery Telephony
Figure 28. Circuits of Local Battery Telephone Sets
Figure 29. Local-Battery Telephone Set, Excluding Handset
Handset Switch.
Figure 30. Handset with Push-to-Talk Switch
Handset.
Structure of handset.
Induction Coil.
Figure 35. Local-Battery Telephone Set with Induction Coil
Principles of Induction Coil.
Summary. - SS03300077
Chapter 5. Common-Battery Telephony
General Features of Common-Battery System.
Basic Circuits of Common-Battery System.
Direct-current paths of simple common-battery circuit.
Talking path in simple common-battery circuit.
Common-Battery Switchboard.
Figure 38. Simple Common Battery Circuit
Description of front of switchboard.
Description of front of switchboard-cont.
Figure 39. Typical Non-multiple Common Battery Switchboard
Operation of Common-Battery Switchboard.
Figure 40. Simplified Common-Battery Cord Circuit
Figure 41. Simplified Common-Battery Cord and Line Circuit
Tracing a call through switchboard.
Basic Components of Common-Battery Cord and Line Circuits.
Figure 42. Tracing a Call from Station 1001 to Station 1002.
Figure 43. Common-Battery Switchboard Cord and Plug
Common battery signal lamps.
Common-battery Telephone Sets.
Figure 45. Basic Circuit of Common-Battery Telephone Set.
Operation of basic circuit.
Common-Battery Sidetone (Booster) Circuit.
Transmitting circuit.
Common-Battery Sidetone-Reduction-Circuit.
Figure 47. Common-Battery Sidetone Reduction Circuit.
Common-Battery Antisidetone Circuit.
Summary of Basic Principles and Components.
Section II. Major Common-Battery Switchboard Circuits.
Structure of typical relay.
Figure 49. Structure of Typical Telephone Relay
Operation of relays-cont.
Lesson 2 Exercises
Lesson 2 Exercises-cont. - SS03300110
Lesson 2 Exercises-cont. - SS03300111
Lesson 2 Exercises-cont. - SS03300112
Lesson 2 Exercises-cont. - SS03300113
Lesson 3: Wire Transmission Principles
Chapter 6. Transmission Lines
Cables.
Figure 51. Types of Cables.
Figure 52. Arrangement of Twin Pair
Characteristics of Transmission Line.
Figure 53a. Short and Long Line.
Figure 54. Long Line and Its Equivalent Circuit (Distributed Constants).
Characteristic Impedance.
Long Lines.
Figure 56. Characteristic Impedance of Long Line
Transfer of Power to Transmission Line.
Maximum power transfer-cont.
Figure 58. Variation of Power Transfer
Application of maximum power transfer theorem to transmission line.
Attenuation.
DB table.
Loading of Transmission Line.
Figure 61. Typical Loading Coil and Symbol
Interference on Transmission Lines.
Inductive coupling.
Figure 62. Causes of Crosstalk.
Capacitive coupling.
Reduction of Interference on Transmission Lines.
Use of repeating coils.
Summary. - SS03300139
Summary-cont. - SS03300140
Chapter 7. Special Circuits
Simplex Circuit.
Figure 65. Typical repeating coil and symbol
Figure 67. Simplex Telephone Circuit.
Current Paths in Simplex Circuit.
Path of simplex-circuit current.
Advantages and Limitations of Simplex Circuit.
Phantom Telephone Circuit.
Figure 70. Phantom Telephone Circuit
Path of side-circuit current.
Advantages and Limitations of Phantom Circuits.
Simplexed-Phantom Circuit.
Operation.
Figure 72. Composite Circuit
Composite Circuit.
Figure 73. Line Terminating and Composite Panel
Summary. - SS03300157
Summary-cont. - SS03300158
Lesson 3 Exercises
Lesson 3 Exercises-cont. - SS03300160
Lesson 3 Exercises-cont. - SS03300161
Lesson 3 Exercises-cont. - SS03300162
Lesson 3 Exercises-cont. - SS03300163
Lesson 4: Fundamental of Teletypewriter
Chapter 9. Introduction to Teletypewriter Communications
Single channel radio teletypewriter system
The Teletypewriter Code.
Rate of Transmission in a Teletypewriter System.
Bits per second.
Other Teletypewriter Terms
Introduction to DC Teletypewriter Circuits.
The One-Way-Only Teletypewriter Circuit.
The Half-Duplex Teletypewriter Circuit.
The Full-Duplex Teletypewriter Circuit.
Using Polar Line Signals.
How the Polar Send Relay Works.
Figure 84. The Send (Polar) Relay Wired for Neutral-to-Polar Operation
The Polar Half-Duplex Teletypewriter Circuit.
Figure 85. Half-Duplex Teletypewriter Circuit -- Polar Line Signals
The west loop circuit.
The Polar Full-Duplex Teletypewriter Circuit.
Figure 86. Full-Duplex Teletypewriter Circuit -- Polar Line Signals, Two-Way Transmission.
The Simplexed Teletypewriter Circuit.
The Simplexed Teletypewriter Phantom Telephone Circuit.
Important Points to Remember.
Lesson 4 Exercises
Table 3-1. Teletypewriter Code Characteristics
Lesson 4 Exercises-cont. - SS03300189
Lesson 4 Exercises-cont. - SS03300190
Lesson 4 Exercises-cont. - SS03300191
Lesson 4 Exercises-cont. - SS03300192
Lesson 4 Exercises-cont. - SS03300193
Lesson Solutions - SS03300194
Lesson Solutions-cont.
Introduction to Telephone and Telegraph Transmission
Chapter 1. Sound
Nature of Sound.
Figure 1. Generation of Sounds
Transmission of Sound.
Figure 2. Sound Wave Produced by Vibrating Blade
Representation of Sound Waves.
Figure 3. Waveform of Simple Sound
Velocity and Wavelength.
Wavelength-cont.
Complex Sounds.
Voice Sounds.
Characteristics of Sound.
Characteristics of Speech.
Frequency Range of Voice Sounds.
Sound Power.
Hearing.
Face-to-Face Conversation.
Conversation by Telephone.
Summary-cont. - SS03300024
Summary-cont. - SS03300025
Chapter 2. Transmitters and Receivers
Telephone Transmitter.
Telephone transmitters.
Carbon Transmitter.
Operating principle of carbon transmitter-cont.
Application of operating principle to carbon transmitter.
Structure of Carbon Transmitter.
Figure 11. Carbon Transmitter
Figure 12. Modern Transmitter
Noise-Canceling Transmitter.
Telephone Receivers.
Magnet-Diaphragm Receiver.
Figure 15. Operation of Magnetic Diaphragm Receiver
Operating principle of magnetic-diaphragm receiver-cont.
Figure 16. Waveforms in Simple Telephone System
Structure of Modern Receiver.
Figure 17. Action of Soft Iron-ore Electron Agent on Diaphragm
An acoustical network couples
Figure 18. Telephone Receivers
Circuit Diagrams.
Types of circuit diagrams
Figure 20a. Handset, Disassembled
Reading of Schematic Diagrams.
Figure 21. Types of Circuit Diagrams
Telephone Symbols.
Summary - SS03300051
Summary-cont. - SS03300052
Figure 1-1. The sine wave.
Lesson 1 Exercises-cont. - SS03300054
Lesson 1 Exercises-cont. - SS03300055
Lesson 1 Exercises-cont. - SS03300056
Lesson 1 Exercises-cont. - SS03300057
Lesson 1 Exercises-cont. - SS03300058
Lesson 2: Telephone Systems
Chapter 3. Introduction to Telephone Systems
Figure 23. Simple telephone circuit.
Telephone Switchboard.
Telephone Central Office.
Telephone System.
Figure 27. Telephone Exchanges Connected by Trunks
Summary-cont. - SS03300066
Chapter 4. Local-Battery Telephony
Figure 28. Circuits of Local Battery Telephone Sets
Figure 29. Local-Battery Telephone Set, Excluding Handset
Handset Switch.
Figure 30. Handset with Push-to-Talk Switch
Handset.
Structure of handset.
Induction Coil.
Figure 35. Local-Battery Telephone Set with Induction Coil
Principles of Induction Coil.
Summary. - SS03300077
Chapter 5. Common-Battery Telephony
General Features of Common-Battery System.
Basic Circuits of Common-Battery System.
Direct-current paths of simple common-battery circuit.
Talking path in simple common-battery circuit.
Common-Battery Switchboard.
Figure 38. Simple Common Battery Circuit
Description of front of switchboard.
Description of front of switchboard-cont.
Figure 39. Typical Non-multiple Common Battery Switchboard
Operation of Common-Battery Switchboard.
Figure 40. Simplified Common-Battery Cord Circuit
Figure 41. Simplified Common-Battery Cord and Line Circuit
Tracing a call through switchboard.
Basic Components of Common-Battery Cord and Line Circuits.
Figure 42. Tracing a Call from Station 1001 to Station 1002.
Figure 43. Common-Battery Switchboard Cord and Plug
Common battery signal lamps.
Common-battery Telephone Sets.
Figure 45. Basic Circuit of Common-Battery Telephone Set.
Operation of basic circuit.
Common-Battery Sidetone (Booster) Circuit.
Transmitting circuit.
Common-Battery Sidetone-Reduction-Circuit.
Figure 47. Common-Battery Sidetone Reduction Circuit.
Common-Battery Antisidetone Circuit.
Summary of Basic Principles and Components.
Section II. Major Common-Battery Switchboard Circuits.
Structure of typical relay.
Figure 49. Structure of Typical Telephone Relay
Operation of relays-cont.
Lesson 2 Exercises
Lesson 2 Exercises-cont. - SS03300110
Lesson 2 Exercises-cont. - SS03300111
Lesson 2 Exercises-cont. - SS03300112
Lesson 2 Exercises-cont. - SS03300113
Lesson 3: Wire Transmission Principles
Chapter 6. Transmission Lines
Cables.
Figure 51. Types of Cables.
Figure 52. Arrangement of Twin Pair
Characteristics of Transmission Line.
Figure 53a. Short and Long Line.
Figure 54. Long Line and Its Equivalent Circuit (Distributed Constants).
Characteristic Impedance.
Long Lines.
Figure 56. Characteristic Impedance of Long Line
Transfer of Power to Transmission Line.
Maximum power transfer-cont.
Figure 58. Variation of Power Transfer
Application of maximum power transfer theorem to transmission line.
Attenuation.
DB table.
Loading of Transmission Line.
Figure 61. Typical Loading Coil and Symbol
Interference on Transmission Lines.
Inductive coupling.
Figure 62. Causes of Crosstalk.
Capacitive coupling.
Reduction of Interference on Transmission Lines.
Use of repeating coils.
Summary. - SS03300139
Summary-cont. - SS03300140
Chapter 7. Special Circuits
Simplex Circuit.
Figure 65. Typical repeating coil and symbol
Figure 67. Simplex Telephone Circuit.
Current Paths in Simplex Circuit.
Path of simplex-circuit current.
Advantages and Limitations of Simplex Circuit.
Phantom Telephone Circuit.
Figure 70. Phantom Telephone Circuit
Path of side-circuit current.
Advantages and Limitations of Phantom Circuits.
Simplexed-Phantom Circuit.
Operation.
Figure 72. Composite Circuit
Composite Circuit.
Figure 73. Line Terminating and Composite Panel
Summary. - SS03300157
Summary-cont. - SS03300158
Lesson 3 Exercises
Lesson 3 Exercises-cont. - SS03300160
Lesson 3 Exercises-cont. - SS03300161
Lesson 3 Exercises-cont. - SS03300162
Lesson 3 Exercises-cont. - SS03300163
Lesson 4: Fundamental of Teletypewriter
Chapter 9. Introduction to Teletypewriter Communications
Single channel radio teletypewriter system
The Teletypewriter Code.
Rate of Transmission in a Teletypewriter System.
Bits per second.
Other Teletypewriter Terms
Introduction to DC Teletypewriter Circuits.
The One-Way-Only Teletypewriter Circuit.
The Half-Duplex Teletypewriter Circuit.
The Full-Duplex Teletypewriter Circuit.
Using Polar Line Signals.
How the Polar Send Relay Works.
Figure 84. The Send (Polar) Relay Wired for Neutral-to-Polar Operation
The Polar Half-Duplex Teletypewriter Circuit.
Figure 85. Half-Duplex Teletypewriter Circuit -- Polar Line Signals
The west loop circuit.
The Polar Full-Duplex Teletypewriter Circuit.
Figure 86. Full-Duplex Teletypewriter Circuit -- Polar Line Signals, Two-Way Transmission.
The Simplexed Teletypewriter Circuit.
The Simplexed Teletypewriter Phantom Telephone Circuit.
Important Points to Remember.
Lesson 4 Exercises
Table 3-1. Teletypewriter Code Characteristics
Lesson 4 Exercises-cont. - SS03300189
Lesson 4 Exercises-cont. - SS03300190
Lesson 4 Exercises-cont. - SS03300191
Lesson 4 Exercises-cont. - SS03300192
Lesson 4 Exercises-cont. - SS03300193
Lesson Solutions - SS03300194
Lesson Solutions-cont.
Introduction to Telephone and Telegraph Transmission
