Can LED TV digital audio out (optical) be connected to a non-DTS Home theater system to get 5.1 channels sound?

A lot depends on how the TV is wired and what the HT is capable of many bargain HDTV's will not convert a signal from other components to surround only to a stereo signal... the surround is limited to the TV signal only also unless your HDTV has ARC it will not output through HDMI only optical. Also the HT unit must also have an optical in and be able to handle the signal given in surround which is not always the case... The more components the signal has to travel through the less likely you are to end up with a surround signal; ,unless the signal starts out in Dolby Digital I don't see how it could be converted to that format...now Dolby Prologic is a different story Prologic is analog so even an analog stereo signal can often times be processed for surround output also it is much easier to pass through a signal intact than to convert it to something it wasn't in the first place....especially if your trying to go from analog to digital....most components use pass through they just pass along the signal as received conversion is an expensive process and often times requires equipment that is very expensive....There is a difference between processing a signal and converting a signal ...