Yealink SIP-T48G User Manual page 163

There are two DND modes:
Phone (default): DND is effective for the phone system.

Custom: DND can be configured for each or all accounts.

To configure the DND mode via web user interface:
Click on Features->Forward&DND.
1.
In the DND block, mark the desired radio box in the Mode field.
2.
Click Confirm to accept the change.
3.
Note
DND mode is configurable via web user interface only.
To activate DND in phone mode:
Tap .
1.
Basic Call Features
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