AstBill
http://astbill.com/whatis
This billing system I have implemented and tested to work for both prepaid
and post paid billing
Simple to setup with asterisk and easy to manage.
Uses:
AstBill
Drupal
Mysql
Apache
Calls pass to Asterisk from ser for termination to PSTN. They are rated and
billed.
I have edited SERWEB to display account records and current prepaid balances
from Astbill database
Check it out it works