What is a Call Detail Record (CDR) in telecommunications?

What is a Call Detail Record (CDR) in telecommunications?

⚡Quick answer -

A Call Detail Record (CDR) is a data record that a telecom system automatically creates for every phone call or communication session. Each record logs key metadata such as start time, end time, duration, calling/called numbers, call status, call type, cost, and the source and destination of the call.



1. Definition of a CDR

A Call Detail Record (CDR) is a data record generated by a telecommunications system or network for each individual phone call or communication session.



2. Key data fields in a CDR

Field

Description

Call Start Time

The date and time when the call or session was initiated.

Call End Time

The date and time when the call or session was terminated.

Call Duration

The length of the call or session, usually measured in seconds or minutes.

Calling Number (Caller ID)

The phone number or identifier of the party making the call.

Called Number

The phone number or identifier of the party receiving the call.

Call Status

Indicates whether the call was successful, unanswered, busy, etc.

Call Type

Whether the call is incoming, outgoing, internal, international, etc.

Call Cost

The cost associated with the call, especially for billing purposes.

Call Source

The location or device from which the call was initiated.

Call Destination

The location or device where the call was terminated.



3. Why CDRs matter

CDRs are crucial for multiple telecom operations:

• Billing: Operators and service providers track and charge customers accurately.

• Fraud detection: Sudden spikes or patterns in CDRs can reveal fraudulent activity.

• Network analysis: Engineers study CDR patterns to optimize network performance.

• Quality of Service (QoS) monitoring: CDR metrics help troubleshoot call-quality and connectivity issues.



4. When a CDR may be missing

If a call or session never reaches the telecom system—or if the system fails to log an event—no CDR is generated. In such cases, usage cannot be tracked or billed accurately, and fraud detection or QoS analysis is impeded.



5. How to confirm a CDR is complete

  1. Locate the CDR entry in your billing or analytics platform.
  2. Verify that all ten data fields listed in Section 2 are present.
  3. Ensure “Call Start Time” and “Call End Time” values are valid timestamps.
  4. Confirm that “Call Duration” equals (End Time – Start Time).
  5. Check “Call Status” for expected values (e.g., “completed”).
  6. If any field is blank or malformed, escalate to your telecom support team.