DeskStand DT-12 on the Nokia 8801

Hi all,

I got my 8801 (regular model) and with it the Desk Stand DT-12, holding
1 battery and the phone.
The Desk Stand has a little button on the back. I tried Manual
(yes!!!!), Nokia website, etc..... to figure out, what it is for.
Does anyone know ? What happens if I press it. Is it a discharge
function or something like it ?

Thanks for your help,

Felix