asterisk users - Apr 2005 - Indicating when other party has answered

Here in Sweden when I make a call through the regular POTS, I get an polarity
reversal when the callee has lift his phone and answered.
Now I've got an Adit 600 with 40 FXS channels and want to
"emulate" an regular POTS. But the Adit doesn't seem to support
polarity reversal.
Is there other standards how to indicate to the caller that the callee has
answered the call? How does it work in other countries?

Thanks!
--
Daniel Nystr?m