What is the purpose of line coding?

Line coding is a method used in digital communication systems to convert digital data into a format suitable for transmission over physical media, which often involves electrical signals. The purpose of line coding is specifically to prepare the digital signals for transmission by modulating the electrical properties of the medium through which they will travel.

In this process, different code techniques can be applied to represent binary data. This may involve changing the voltage levels to represent different binary states, facilitating the effective and efficient transmission of the digital information over various mediums. By modulating the electrical charge, the system ensures that the signals can be accurately interpreted at the receiving end, even across potentially noisy channels.

The other options, while related to communication and data handling, do not capture the essence of line coding's primary role. Amplifying a signal refers to increasing its power without altering its content; establishing a firewall pertains to network security by controlling incoming and outgoing traffic; encrypting data transmission is focused on securing the data content itself rather than preparing it for transmission. Thus, the primary role of line coding is accurately reflected in its function of modulating electrical charges to ensure effective data transmission.