Altigen AltiContact Manager Version 5.0 Administration Manual page 345

Note:
Options in the window are disabled unless One Number Access
has been enabled as a No Answer option in the Answering page
of Extension Configuration.
Figure 11. Enable One Number Access, Answering Page
Also, if the Enable Do Not Disturb option is selected in the
Answering window, the call is forwarded to voice mail regardless
of ONA settings.
To configure ONA, select the extension number from the Agent/
Supervisor/Extension side window list, then click the One Number
Access tab.
Figure 12. One Number Access window, Agent Extension Configuration
AltiContact Manager Administration Manual
Agent Configuration
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