Hi,
 

The accounting process collects accounting data for each call leg created on the Cisco voice gateway. 
You can use this information for post-processing activities such as generating billing records and 
network analysis. Voice gateways capture accounting data in the form of call detail records (CDRs) 
containing attributes defined by Cisco. The gateway can send CDRs to a RADIUS server, syslog server, 
or to a file in .csv format for storing to flash or an FTP server. For information about generating CDRs, 
see CDR Accounting for Cisco IOS Voice Gateways at this link: http://www.cisco.com/en/US/docs/ios/voice/cdr/developer/guide/cdrover.html

 
BR