CDR - Call Detail Record

CDR is the computer generated record whenever an event occurs in a telephone exchange.
A CDR is made of fields that describes the exchange.

such fileds may include :

additional digits on the called number used to route or charge the call
the result of the call
the route by which the call entered the exchange
the route by which the call left the exchange

computer networks are widely used for transporting cdr files.
These details are later also used for billing purposes.The billing system also receives records from long distance service providers, roaming partners etc. The billing system then updates these CDRs to their correct customer and rating information. Then these details are combined into a single invoice that is sent to the customer.

Call detail records can be used later for reporting solutions as well because they hold a huge collection of information.

Three types of call detail records are,

- Fixed-fee CDRs — Generated when a subscriber logs into the SMS network and receives a password in the form of a text message. A fixed-fee CDR provides network access for a specified time period.

- Session CDRs — A session CDR records the length of time of the WLAN session and the number of bytes of data sent and received.

- Partial CDRs — Generated periodically during a WLAN session. A provider can specify how frequently a system generates a partial CDR by specifying time and volume.