DS0 is a term used in telecommunications to refer to a digital signal level that can carry data at a rate of 64 kilobits per second (kbps). It is the basic building block for digital transmission systems and is commonly used in T1 lines, which are standard digital transmission links in North America. In a T1 line, 24 DS0 channels can be combined to create a higher capacity signal, allowing for the transmission of voice and data simultaneously. This makes DS0 essential for efficient communication in both residential and business environments.