Unit 2

Lesson 1 - Communication and Signals

   Different Signals, Different Media

Data networks transmit signals using three types of energy, and each one of these signals travels over a particular type of physical medium:

Electrical current over copper wire

Light pulses over plastic or glass fiber

Radio waves through free space

Later in this unit, we will explain how signals travel over each of these physical media.

   Activities

See the Activities and Extended Activities section in Unit 2 Lesson 1 in your textbook Introduction to Networking to test what you have learned so far.

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