SO I got a used LG ACC97WK and tis missing the receiver adapter for the speakers it plug is a USB like interface, so I suppose the "adapter" is a USB like plug that adapters to bear speaker wire or plugs, if I can not find a proper adapter I will just make one myself out of USB cable I guess. Looking at a manual I found its the signal cable thats missing.
Check here, and send them an email, asking them where to get the part you need. They should be able to tell you........... http://us.lge.com/support/support.jsp Good luck!