When one terminal sends a typed message to another over data networks, the content is converted to digital signals, transmitted, and reconstructed at the destination. What is this system commonly called?

Introduction / Context:
Exchanging messages between computer users is a fundamental network application. The process converts text into digital signals, transports them over various media (cable, telephone, satellite), and reconstructs the message at the destination inbox.

Given Data / Assumptions:

• Point-to-point user messaging over networks.
• Store-and-forward delivery with mail servers is typical.

Concept / Approach:
The well-known term for this is electronic mail (email). It comprises user agents (mail clients), message transfer agents (servers), and protocols for submission, relay, and retrieval.

Step-by-Step Solution:

Verification / Alternative check:
Inspect message headers to see SMTP hops; observe that the content was transported and restored exactly or with defined encodings (e.g., quoted-printable, base64 for attachments).

Why Other Options Are Wrong:

• Paperless office: A broad concept reducing paper, not specifically messaging.
• Global network: A generic term, not a messaging system.
• Electronic newspaper: One-to-many publishing, not interpersonal messaging.
• None of the above: Incorrect because "Electronic mail" precisely describes it.

Common Pitfalls:
Confusing chat/instant messaging with email; both send text, but email is store-and-forward and uses distinct protocols and addressing.

Final Answer:
Electronic mail