I want to know the very same thing. I have two dvd players. One sometimes does not want to play a particular dvd while the other plays it just fine. My 5.1 DTS receiver has only 1 digital audio coaxial input, as Peter says. Without a "A B switch" I have to connect a different DVD player by pulling out my entertainment center and reconnect the other coax cable. Why can't a digital coax AB switch be created for this inconvenience?