Allworx 92x phones have a DND BLF (hard button) that will Blink if the Presence setting on phone is set. DND cannot be turned off by pressing DND- Presence must be set to In Office and then DND can be disabled.
Presense setting on the handset itself is a Soft Button that can be pressed - and then using the navigation keys, to right of the LCD can be set to In Office., or this can be changed in the Allworx Portal.