Digital Optical Miniport for IMac(early 2009)

Is they a way to configure the settings for the digital out on the IMac? Because I got the toslink adapter for the IMac and plugged it in and it did not work. I called customer support from where I bought the Toslink adapter and they sent me a new one, I tried it again and it still didn't work. I am troubled on this situation :/. If anyone can help me with this problem it woud be a great pleasure.

You have to tell us more than "it didn't work".

What did it do?
What piece of hardware is the other end plugged into?
Did you open up Sound preferences and change the output?
What version of OS X are you using?

Optical output of iMac

I have a question, somewhat related to this link. I would like to use my Altec Lansing 5.1 speaker system with iMac, It seems that a Toslink or a SPDIF cable is required to do this, but my speaker system does not have optical input. So my question is what type of device is required to convert optical input to three-channel (R-C-L) output. Can you help me here?
Thanks in advance.