POTS & Dial up - Dial-Up and Modems

Need for Connectivity: As computer usage increased in the 20th century, the necessity for computers to connect and share data became evident.
Primitive Networking: Before the advent of technologies like Ethernet, TCP, or IP, early computer networks relied on simpler technologies designed for connecting devices in close proximity.

Innovation at Duke University: In the late 1970s, two graduate students at Duke University sought better methods to connect computers over longer distances to share information, specifically bulletin board material.
Utilizing the Telephone Network: They recognized the existing public switched telephone network (PSTN), also known as plain old telephone service (POTS), as a viable infrastructure for data transmission.
Development of Usenet: They created a network system named Usenet, which facilitated communication between different locations (e.g., colleges/universities) using dial-up connections.
Dial-Up Description: Dial-up connections involve using POTS, where users dial a phone number to establish a connection. The sound of connection might evoke nostalgia for those familiar with it.

Role of Modems: A modem (modulator-demodulator) converts computer data into audible signals for transmission over telephone lines, a process essential for data communication before broadband.
Line Coding Analogy: Similar to how line coding transforms binary data into electrical charges on Ethernet cables.
Baud Rate Explanation: The baud rate measures the speed at which bits can be transmitted over a line.
- Early Baud Rates:
- Late 1950s: about 110 bits per second.
- Late 1970s (Usenet era): around 300 bits per second.
- 1990s (widespread dial-up): up to 14.4 kilobits per second.

Improvements Over Time: Although those rates have improved significantly, broadband technology shifted connectivity paradigms, rendering dial-up less common.
Current Relevance of Dial-Up: While rare, dial-up connections are still present, especially in rural areas where they may be the only internet option available.
Reflection on Technology: Understanding dial-up's importance helps contextualize the technological advancements in internet connectivity, despite it being largely obsolete today.