In order to get 5.1 from a DVD you need to connect your DVD player to the 2105 with a digital connection, NOT the composite (you may connect both if you wish, but it's not necessary).
The 2105 has 4 digital inputs, 1 coaxial, and 3 optical. Most DVD players have outputs for both, but some set top cable or satellite boxes only have one or the other. Check to see if you have a component that has ONLY a coaxial output. If you do then, you'll have to use an optical connection for your DVD player.
You'll need either a
digital coaxial cable,
or a
toslink digital optical cable.
Don't hook BOTH up, just one or the other, and either will suffice.
If you click on the links above, you'll see that a decent digital cable will cost you less than $10 plus shipping. You can pay more if you wish. Radio Shack will have both if you're in a hurry.
Two things which can be confusing to a person unfamiliar with optical cables are, 1) the little square black thing sticking out of an optical jack is a protector and is meant to be removed before attempting a connection. Just pull the little sucker out (I recommend tucking it away somewhere and hanging on to it. I have all mine in a little medicine bottle) Some components don't have that little black thing. The input is covered by a little trap door which will swing out of the way when the cable is inserted into the input. And 2) There will be a small, clear, soft plastic nipple on each end of an optical digital cable. These are also to be removed, and saved, before connecting.
OOPS! I forgot number 3. The cable is shaped so that it can only go into the jack one way. Check the shape of the the jack and the cable end to be sure you match them up. When you have it correct, the cable end goes in the jack quite easily with a satisfying little "snick."
If you go with the coaxial connection, disregard the above.
Don't forget that you'll have to go into the 2105's input setup menu and "assign" the input you've chosen to the DVD player (see page 29 of the 2105's manual).
