CDR-Stats is a CDR viewer for Asterisk Call Data Records. (The Freeswitch version is under development). It allows you to interrogate your CDR to provide reports and statistics via a simple to use, yet powerful, web interface.
It is a replacement for Asterisk-Stat which has been in production for over seven years and is a component of the very popular open source PBX application, FreePBX, and as such has been installed many millions of times. This version adds greater security, versatility, and the potential for easy customisation.
CDR-Stats is a separate product from A2Billing and as such has its own website.