MyPBX U300 Extension User Guide6/101.2.3 Do not Disturb (DND)Do Not Disturb service is used to turn off the phone bell. If it’s enabled, incoming callers will be routed to thevoicemail box (if enabled); otherwise they will be disconnected automatically.1.2.4 Ring OutRing Out is used to define the ringing time of the extension. If the ringing time exceeds theconfigured time, the extension would stop ringing.1.2.5 Mobility Extension NumberMobility Extension Number is used to enable the cell phone to work as a mobile extension. If acell phone number is set as the mobility extension number, once it calls MyPBX, the cell phonewould have all authority of extension. In this way, the user is able to check the voicemail, call theother extension, PSTN or mobile numbers via cell phone.