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What Are Call Detail Records (CDRs)?

by Kevin Bartley

A call detail record relays key metadata about how and when your business phone system is being used. Here's an FAQ about CDRs for reporting and billing.

A call detail record (CDR) provides information about calls made over a phone service. A CDR report can offer businesses exact answers about where, when, and how calls are made for reporting and billing purposes.

What is a Call Detail Record (CDR)?

A CDR provides metadata - data about data - on how a specific phone number and/or user is utilizing the phone system. This metadata typically includes:

  • When the call took place (date and time)
  • How long the call lasted (in minutes)
  • Who called whom (source and destination phone numbers)
  • What kind of call was made (inbound, outbound, toll-free)
  • How much the call cost (based on a per minute rate)

CDRs can also include SMS messaging metadata and any other official communications transmission. However, the contents of the messages/calls are not revealed through the CDR. The call detail record simply shows that the calls or messages took place, and measures basic call properties.

Consider the following CDR report as an example, generated from a user on a cloud phone system.

Sample Call Detail Record CDR report

Why are CDRs important?

A CDR log lists every billable communications transmission on your phone system. This allows phone companies to generate your phone bills, and lets you keep definite records of how and when your phone system was used. They are primarily used by businesses to assist in call reporting and billing.

Billing departments use CDRs to resolve disputes, keep records of how funding is spent, and log usage of the telephone system. IT departments can also use CDRs to determine if there were any disruptions in phone service.

CDRs can be used to identify calling trends and gain insights into employees’ use of phones. This allows a business to make better management and personnel decisions by analyzing patterns and trends..

What does a CDR report include?

A CDR report typically shows data broken down either by user or by phone number. A CDR report generated for a single user can show specific metrics, such as call volume and minutes, for that person. A CDR for a phone number gives you more of a bird's eye view of how your phone system is used on a business-wide level.

Generating CDR reports for individual employees is useful to find out who's on the phone the longest, what the call durations are, and how much money each employee spends per call. This can lead to better management of your employees, and save resources for your business.

A CDR report for a particular phone number, on the other hand, can indicate how much money specific offices or groups are spending on calling minutes. This is useful if your business has several phone numbers for different locations or departments. This kind of report allows you to take an aggregate look at your company's calling activities.

Are any items left off CDR reports?

Communications transmissions that do not cost money are generally kept off the CDR. Many Voice over Internet Protocol (VoIP) services offer free SIP-to-SIP calling. This is when a VoIP phone calls another VoIP phone without ever going through the public switch telephone network (PSTN).

These calls are not listed on the CDR, because they're not billed. However, calls made to landlines, mobile phones, and international numbers are always logged, because they're charged on a per minute basis.

However, cloud phone systems usually offer ways to view the call logs of Internet calls that are not billed. This data is often found in the "call history" or "recent calls" of your web phone service.

Recent calls list in the OnSIP app
Recent calls list in the OnSIP app

How do I generate a CDR report?

CDR reports are typically included as part of the reporting features of a business VoIP service. Admin users can sign in to a web portal to view and download reports for given time periods. CDRs may also be found listed inside formal phone bills mailed to you by your provider.

Who can access CDRs?

Anyone with admin privileges on your business phone system can generate CDRs for individual employees or phone numbers.

CDRs are not protected by the 4th Amendment, and law enforcement can obtain them without a warrant. Although they do not contain call recordings or defining location information, call detail records can establish calling patterns between a network of people. A piece in the New Yorker examined the efficacy of call detail records in criminal trials, and found that CDRs ultimately offer the "kind of information that helps cell companies manage their networks, not track phones."

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Better Calling Data

Call detail records provide you with detailed logs about your phone activity. You can use the data to verify billing disputes, monitor employee phone activity, and keep track of when, where, and how your phone system is used.

If you're looking for deeper insights into your calling activity, you may want to consider call center reporting features. For example, OnSIP's Enhanced Queues feature comes with a real-time dashboard of your different calling queues and custom reporting.

OnSIP Smart Queues Dashboard and Reports
OnSIP Enhanced Queues Dashboard

CDRs can study calls that have already taken place, but Enhanced Queues give you the ability to interact with both employees and customers as the call is unfolding. The dashboard allows you to observe average caller wait times, run historical reports, and implement call center features to streamline your business phone system. This information can help you measure various call tracking metrics to optimize your team's phone performance.

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