Explain the term modem.

Explanation

### Step-by-Step Text Solution:

1. **Definition of Modem**:
A modem is a device that performs two primary functions: modulation and demodulation. The term "modem" itself is a contraction of these two words.

2. **Understanding Modulation**:
- Modulation is the process of converting low-frequency signals, which are typically used in communication systems, into high-frequency signals.
- This is necessary because low-frequency signals cannot be transmitted effectively over long distances.
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