The cdr_manager.conf file simply contains a [general] heading and a single option, enabled, which you can use to specify whether or not the Asterisk Manager API generates CDR events. If you want CDR events to be generated, you will need the following lines in your cdr_manager.conf file:

[general]
enabled=yes

The Manager API will then output CDR events containing the following fields:

Event: Cdr
AccountCode:
Source:
Destination:
DestinationContext:
CallerID:
Channel:
DestinationChannel:
LastApplication:
LastData:
StartTime:
AnswerTime:
EndTime:
Duration:
BillableSeconds:
Disposition:
AMAFlags:
UniqueID:
UserField: