The Quadrature Amplitude Modulation (QAM) scheme works by changing the amplitude of two out-of-sync carrier waves to successfully transmit data. A QAM tuner enables users to obtain reception of unencrypted digital and HD stations through a cable connection and without the use of a set-top box.
Most cable and digital televisions manufactured after 2006 are equipped with an internal QAM tuner. To find out if a television has the tuner, consumers can reference the "specifications" section of their owner's manual. Another way is to look at the remote control; the device of such televisions often bear a "dot" or "dash" button used in the tuning process.