Final answer:
The correct answer is Option b) Analog; digital. Analog networks used in telephones involved continuous signals over wires, whereas digital computer networks employed binary data transmission which is less error-prone and more efficient.
Step-by-step explanation:
The phone system originally used analog networks, while computer networks have almost all used digital from the beginning. Therefore, the correct answer is Option b) Analog; digital.
Analog networks for telephones were based on continuous signals that varied over time, representing fluctuations in voice frequency. These were carried over copper wires and were susceptible to noise and signal degradation. On the other hand, digital networks used for computer communications involve the transformation of data into binary format, consisting of ones and zeros, which is more efficient for transmission and less susceptible to errors.
The shift from analog to digital technology allowed multiple firms to use the same transmission mechanisms such as microwave and satellite, increasing competition among service providers. This change corresponded with the growth of cellular phone systems, which provided a leap in the type of infrastructure required compared to traditional wired telephone networks.