Sound synch Arri 16 BL EQ

[Lukas Heinser]

Hi guys! I recently bought an Arri 16 BL EQ and am wondering about the mode switch you can see in the image, which is for making "quick changes between sound speed and non-sync speed" as the manual says. But it doesn't say which is which. The switch has three possible positions. It can be parallel to the body, one step to the right and even more to the right (in an almost 90 degrees angle to the body). Does anyone of you know which of these possibilities are for synch-speed?

My goal is to be able to record audio digitally independently with an external recording device and to then line it up with the image.

Thank you already!