NEC Univerge SV8100 Features And Specifications Manual page 461

UNIVERGE SV8100
3. Dial the DND option code.
0 = Cancel DND
1 = Incoming Trunk Calls Blocked
2 = Paging, Incoming Intercom, Call Forwards and Transferred Trunk Calls Blocked
3 = All Calls Blocked
4 = Call Forwards Blocked
SV8100 Features and Specifications Manual
Issue 1.0
2 - 437