Finger printing is a facility whereby a STB, when commanded from the headend, outputs its unique identity (such as its serial number) on to the screen of the TV to which it is connected. Finger printing is an effective anti piracy measure.
An unscrupulous last mile operator may install a bank of STB, each outputting unscrambling video and audio signals of various pay channels. These signals could then be re-modulated and fed out as a pirated, unscrambled bouquet. The Master Headend can, in such cases, activate finger printing and identify each of the errant STBs on the pirate network and shut them off.
Got these details from an article.
Sent from my GT-I9500