[Asterisk-Users] calling card application

[Wolfgang Pichler]

hi all,

i'd like to know if is possible with asterisk / standard pc(server) /
Wildcard TE410P (4 port T1/E1) to implement a calling card application.

This calling card application should work as follows:
- User's can buy credits at out company (this credit gets stored in a
database - with the telephone number associated with the credit) for his
telephone number (which is always a mobile phone)
- If the user wants to dial a long distance number - then he simple
calls our "calling card application number" (where our Wildcard sits on
a E1).
- Then asterisk checks if the user is authorized with his mobile number.
- If the user is authorized - then let him enter the destination number
- if the user is not authorized - then give back a text
- Then connect to the long distance number and establish the call (but
hang up the call if the user credit is to low)
- The outbound call also goes over our WildCard card.

Additionally there should be:
- The outgoing call should get "least coast" router between several
providers (we have a table for which provider is the best for which
destination)
- It would be nice if the call could ask for his credit (or he always
gets a message "Your credit is ..."
- Also it would be nice - if it were possible for users to store the
number the want to call in their phone book (eg. "calling card
application number...pause...long distance number) - so that they don't
have to remember the number.

I have already found something like this - its at:
http://www.voip-info.org/wiki-Asterisk+callingcard - it seems to be
nearly the same as for what i was searching (the authorization is based
on a PIN which the user have to enter - but beside of that it is the
same)

Is, what i have tryied to explain, so possible with asterisk ?
If not - does there exists anything else with which it would be possibe
(gnu bayonne?) ?
Where are the possible problems ?

Have someone already used app_prepaid in production ?

hope you have some hints for me

PS: sorry for my bad english

best regards
Wolfgang