Using MPEG encoding, digital cable is an enhanced service from the cable companies that provides an option to the regular analogy TV. Advantages are on-screen program guides, a sharper picture and more channels of paid and on-demand programs. Unlike "digital satellite TV," which requires a dish on the roof, digital cable, also known as "digital terrestrial TV (DTTV)," is delivered over the same coaxial cable wired into the home or office.