With the ever increasing pace of modern technology, amateur radio was certain to embrace the new methods of digital communication. Indeed, modern digital voice modes encode speech into a stream of data before transmission, while the receiver decodes this stream back into a normal audio signal.
In the past the only way amateur radio operators used to send data was using conventional analogue methods. This is often achieved by inserting the data stream as an audio signal in place of voice. It should be noted that this method of data transmission is far from dead, and is still thriving. Further information on data modes (digimodes) can be found on this page.