Aastra 7106A User Manual page 10

Do not disturb, DND
When you activate DND, calls to your extension is not shown.
Outgoing calls can be made as usual.
Activate DND:
Lift the handset and press numeric keys * 2 7 #, Replace the handset.
Deactivate DND:
Lift the handset and press numeric keys # 2 7 # Replace the handset.
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