1. Electronic Communication
Chapter 7

2. Electronic Communication System:
Communication systems have three parts- transmitter, receiver, channel.
Channel- Carries the message from the transmitter to the receiver, if the channel uses electric energy to carry the message it is an electronic communication system.

3. Telegraph: The 1st electronic communication system.
Started with a pen that wrote out the marks but was soon changed to the clacking form we are familiar with.
Uses Morse Code

4. Telephone: Invented by Alexander Graham Bell (teacher of the deaf)
Telephone switching- how one telephone is connected to another one, now done by computer.
Fiber Optic cables now allow more than 10,000 conversations on one line.

5. Radios: Radio signals with low frequencies have long wavelengths.
Those with high frequencies have short wavelengths.

6. Electronic Communication:
In an electronic communication system, the channel carries an electronic or electromagnetic signal.
The telephone is the most commonly used form of electronic communication.
In radio, communication, the message is sent through the air from a transmitting antenna to a receiving antenna some distance away.
A number of computers or computer devices joined together is a network.

7. Transmitting and Receiving Systems:
Telegraph
Telephone
Radio
Television
Satellite Communication
Fiber Optic Communication

8. Data Communication Systems:
Centralized Computing- All processing is done in one computer with terminals and printers attached.
Distributed Computing- Small computers from other locations can send larger, more difficult jobs to a larger computer.

9. Modems:
Modem- a device used to send data signals over analog communication channels such as telephone circuits.
Modulation- turning data signals into audio signals.
Demodulation- turning audio signals into data signals.

10. Recording Systems: Magnetic recording tape Magnetic recording disk
Phonograph records
Optical disk

11. Modern Types of Communication Services:
Teleconferencing
Telecommuting
Electronic Banking