A device that connects one computer to another across ordinary telephone lines is called

Options

A. Transducer
B. Fax
C. Modem
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for a device that connects one computer to another using ordinary telephone lines. This implies that the device must be capable of transmitting data over a telephone network.

2. **Analyzing the Options**:
- **Option A: Transducer**: A transducer is an electronic device that converts one form of energy into another (e.g., sound to electrical signals). It does not specifically connect computers over telephone lines.
- **Option B: Fax**: A fax machine is used to scan and send documents over telephone lines. While it does use telephone lines, it is not primarily designed to connect computers.
- **Option C: Modem**: A modem, which stands for modulator-demodulator, is designed to convert digital signals from a computer into analog signals that can be transmitted over telephone lines and vice versa. This makes it suitable for connecting computers over such lines.
- **Option D: None of the above**: This option suggests that none of the provided devices are correct, but we have identified a suitable option.

3. **Choosing the Correct Answer**: After analyzing each option, it is clear that the modem is the device that connects one computer to another across ordinary telephone lines. Therefore, the correct answer is **Option C: Modem**.

**Final Answer**: The device that connects one computer to another across ordinary telephone lines is called a **Modem**.

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