Unless you have a office phone like the Cisco SPA series phone there isn’t one button to turn on for DND (do not disturb). The short code to turn on and off DND is below:
To turn on:
1. Dial 9979 and press send/dial
To turn off:
1. Dial 9978 and press send/dial
If you are using a provisioned remote or mobile phone dial your main business phone number to get access the the phone system.
When you hear the dial tone dial 9979# to turn on DND
Repeat the same step but dial 9978# to turn off DND