Need some clarifications

by wzis
(Australia)

Questions:
1. When caller is using VoIP but receiver is not, at what point the VoIP will be terminated?
2. In above situation, what codec can be used is controlled by what?
3. When both ends use VoIP, what codec will be chosen is controlled by what?
4. When VoIP service provider says they only support narrow band VoIP codecs, and when both ends's ATAs support G.722 wide band, could wide band call work between the 2 parties?