Good news! Your Sony KDL-40S4100 television has an ATSC tuner so you will be able to receive over-the-air digital programming without a digital tuner or a converter box.
Note: You may still need a cable box to receive digital cable programming, or to view premium or pay-per-view cable programming.
After June 12, 2009, full-power television stations will broadcast in digital only. The switch from analog to digital broadcast television is referred to as the digital TV (DTV) transition. In 1996, the U.S. Congress authorized the distribution of an additional broadcast channel to each broadcast TV station so that they could start a digital broadcast channel while simultaneously continuing their analog broadcast channel.
Congress mandated that February 17, 2009, would be the last day for full-power television stations to broadcast in analog. Then in February 2009 Congress passed the DTV Delay Act which extended the deadline for full-power broadcast TV stations to complete the DTV transition from February 17, 2009, to June 12, 2009. However, Congress did not require stations to continue broadcasting in analog. Some broadcast stations in the U.S. have already switched over and are broadcasting in digital only. The remaining stations will stop broadcasting in analog sometime between now and June 12, 2009.
Sony has been complying with the US Government's mandate by manufacturing our televisions to be compatible with receiving both analog and digital broadcasts.
For more information about this federal government mandate, we recommend you visit the official U.S. government digital TV FAQ website at: http://www.dtv.gov/consumercorner.html. The website explains in detail the upcoming changes and what they mean for consumers.