# Enable Call Timeline for CDR

With the call timeline enabled, each Call Detail Record (CDR) lays out a call's events in the order they happened, from the moment the call starts to the moment it ends. This chronological view gives you a clear picture of what took place during a call and makes it much faster to trace and resolve issues. Follow the steps below to switch it on.

## Before you begin

Your Cloud Voice system must be running firmware version `84.21.0.117` or later.

## Enable the timeline

1. Sign in to the PBX web portal (PBX stands for Private Branch Exchange, the phone system that runs your calls) and go to **Reports and Recordings > CDR**.
2. Open the **CDR (Advanced)** tab and turn on the **Timeline** switch.

   ![The Timeline switch on the CDR Advanced tab](/images/pbx/enable-timeline.png)

3. Confirm the change in the dialog that appears.

   ![Confirmation dialog for enabling the call timeline](/images/pbx/enable-timeline-confirm.png)

   1. If the system asks you to adjust the CDR storage limit, either accept the recommended value or pick a different one from the **Modify Max Number of CDR** drop-down list.

      :::tip
      When in doubt, keep the recommended value. Only change it if you have a specific reason to store more or fewer records.
      :::

   2. Click **OK**.

## What happens next

- Timeline data is now captured for CDR. Any record generated from this point forward will include the full event timeline.

  :::note
  Existing (legacy) CDRs are not backfilled and will not contain timeline data.
  :::

  You can open [new CDRs](/pbx/administrator-guide/view-cdr/) from the PBX web portal and review their [key metrics](/pbx/administrator-guide/key-metrics-for-cdr-details/) whenever you need to.

- If you changed the CDR storage limit while enabling the timeline, that value is copied automatically to the CDR auto cleanup rule at **System > Storage > Auto Cleanup > CDR Auto Cleanup > Max Number of CDR**. The new limit applies after the next system reboot, or at 00:00, whichever comes first.

  :::caution
  When legacy CDRs are present, the system manages the transition as follows:

  1. Once the total number of CDRs hits the limit, legacy records are purged at a 5:1 ratio, five legacy CDRs are removed for each new CDR that is created.
  2. After the last legacy CDR is cleared, the system raises the event notification **Legacy CDRs Have Been Fully Cleaned Up** so you know the cleanup is done.

  Back up any legacy CDR data you want to keep before this cleanup begins, so nothing is lost in the process.
  :::