NEC UNIVERGE SV9100 Features And Specifications page 204

Default Settings
The attendant (extension 101) has Class of Service 15 in all Night Service modes. All other
extensions have Class of Service 1 in all Night Service modes.
If changing Class of Service via Service Code:
An extension can use Service Code 777 to change another extension Class of Service
(Program 20-13-28 = 1).
An extension can automatically block another extension attempt to change their Class of
Service via Service Code 777 (Program 20-13-28 = 0).
The default Service Code for this option is 677 (Program 11-11-24 = 777).
System Availability
Terminals
All Terminals
Required Component(s)
None
Related Features

Night Service
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