11.8.1. Feature Description 
The feature is based on the existing night service. In order to improve
the facilities of network wide night service configuration, the following
enhancements has been implemented:
(Remark: The night service feature does not depend on the type of
the used attendant groups. The following descriptions are valid for Multiple
Queue-MQ groups and Double Queue-DQ groups as well.).
The attendant console activates night mode by clicking the night button
in the Buttons window or by pressing the Night key on the keyboard. The
DAY/NIGHT Service indication in the call control window shows NIGHT.
This can also be achieved by unplugging the handset.