Multiple Short Distance Charging Area

Hi,

Can any one provide the information regarding
1) how multiple area codes are configured in switches like ericcson, lucent, siemens.
2) How the subscriber is represented in these switches. Whether subscribers are represented as Area Code + Exchange Code + Subscriber number or in a different way.
3) Various types of subscriber charging methods in these switches.
5) Is it possible to charge differently from one exchange code to another exchange code of the same area code.
6) How the incoming international calls and incoming national calls are routed to the subscribers of various area codes.
7) How the routing to the PSTN is done from the various area code subscribers of teh same switch.

regards,
Aatrala