Digital signals are discrete, consisting of sequences of 0s and 1s. They are transmitted directly in binary form over communication channels using a modem. Digital signals are preferred over analog because they are not affected by noise or disturbances due to their discrete nature. Bandwidth is the frequency range and data transmission capacity of a channel, with higher bandwidth allowing faster transmission speeds. Networks provide convenient access to shared resources and data from any location, as well as communication and decentralized data processing between organizations.