Go to Phone->Time/Lang, to select local Time Zone for NTP
server.
Go to Phone->Call Feature, to configure Phone-Call Feature.
DND: DND (Do Not Disturb) allows IP phones to ignore any
incoming calls.
Return Code when DND: Determine what response code
should be sent back to server when there is an incoming call if
DND on.
DND On Code: The Code is used to turn on DND on server’s
side, if configured, IP phone will send a SIP message to server
to turn on DND on server side if you press DND when DND is
off.