[Serusers] "Callback on busy" with SER

[Andreas Granig]

Hi,

Just saw an article on 
http://www.zdnet.de/news/tkomm/0,39023151,39132110,00.htm?h (in German) 
where they say that AVM and Iptelorg developed some ISDN features in SIP 
like "callback on busy", "call waiting", "cold hold", "deflection" and 
"3way conference".

I was just wondering:
- how the first one (callback on busy) is implemented and if it is 
possible to do this with the standard ser and without a b2bua
- why the other features are big news since they are possible with some 
help of the involved UACs anyway...

Andy