Digital data is represented as strings of 0s and 1s, while analog data modifies signal properties like amplitude or frequency. Source coding prepares data for transmission by reducing redundancy or converting to digital. Channel coding adds redundant data to allow error detection and correction during transmission. Modulation varies signal properties to transmit information. Multiplexing combines multiple channels into one signal to share a medium, like frequency division multiplexing assigning each a frequency. Code division multiplexing assigns unique codes to differentiate signals in the same spectrum, like code division multiple access used in wireless. Time division multiplexing allows channels to take turns on a channel, like the time slots used in GSM networks.