Final answer:
A modem is the device that detects signals and controls information flow between computers over telephone lines. It converts digital data into analog signals suitable for transmission over phone lines. CD technology and microfilm were also pivotal in the development of information processing.
Step-by-step explanation:
The device that detects signals and controls the flow of information between two computers communicating via telephone line is known as a modem. Modems are essential for converting digital data from a computer into analog signals that can be transmitted over phone lines, and then back into digital form at the receiving end.
Before the widespread availability of broadband internet, modems were the primary means of accessing the internet for many users. Although not directly related to your question, interestingly, in the history of computing, devices like compact discs (CDs) played a significant role in data storage and contributed to the efficient processing of large amounts of information.
These optical media are read by interpreting reflections of a laser beam. In the 1950s, computers relied on complex data management systems, and innovations such as microfilm were used to handle data transfer and processing.