In ScopTEL Telephony revisions prior to 2.7.7 the DND Activate Features Code would allow a device or user to dial the code and activate DND in the telephony database.
Dialing the code when the extension was already in DND enabled status would allow the same code to deactivate DND enabled status.
The same scenario was also true for the DND Deactivate code. The deactivation code could both enable and disable DND status.
While this was convenient for some users this was not ideal for Yealink T2X series phones with firmware revisions prior to x.71.0.137. These phones would execute the DND codes on a reboot to refresh the DND status after the device re-registered. In these cases an extension already in DND disabled status would toggle into DND enabled status after the device finished its reboot.
Since Telephony version 2.7.7 ScopServ has split the DND functions so that the DND Activate code can only ever activate DND enabled status and the DND Deactivate code can only ever deactivate DND enabled status.
If you have devices with hard coded DND buttons mapped to DND Activate *78 and for example you have a Features Code defined for DND Deactivate *79 you will notice that you cannot press the DND button again to disable DND enabled status. To restore the previous behavior you must change the DND Deactivate code to match your DND Activate code. As in this example you must edit your Features Code configuration and set DND Activate *78, DND Deactivate *78 then save and Commit your configuration changes. WARNING: If you decide to implement this behavior ensure any Yealink phones you have on your network are upgraded to a minimum revision of x.71.0.137