The clutch consists of three parts: the outer tube and the two into it plugged into this tube doses. Unfortunately, the doses in the Toslink connector be plugged, clamped loosely into the tube. Once you try one of hineinzustecken plug, comes a counter against the lying box. They can be put into it again, but she sits not too tight. With a little skill you can, however, insert both plugs simultaneously, and with a little luck holds, the construction then. As long as no train is also sustainable.
The loose structure also makes an external light or a loss of information not improbable.
If you want to make sure that the connection is not accidentally disconnected, and the information is not distorted, should also use tape to fix the coupling and the plug. Or even buy a longer cable.