Network Disconnected
The "Network Disconnected" prompt appears on the display and the telephone status light turns on when the phone is not properly connected to the network. The phone also displays the default time and date of 12:00am Jan 1st, 2005 or the equivalent. Check that the cables are tightly connected to the phone and to the wall jack. The phone should automatically detect when it is reconnected and will display the "Network Connected" prompt for a few seconds. However, if changes have been made to your phone’s network settings, you may need to restart your phone.
For more information about connecting your phone, see the Aastra 480i Installation Guide, the section, "Connecting to the Network and to Power".
Check with your system or network administrator for assistance.
Note: f the phone displays
"No Service" you can still use the phone but it is not registered with the Registrar. For more information about registering your phone, see your system administrator.
Restarting Your Phone
You may want to restart your phone to check for updates from the configuation server. You may also need to restart your phone if you have been asked to do so by your network or system administrator, or if you are having problems with your phone.
Note: Your phone will be temporarily out of service during the restart and downloading process.
Important! Do not unplug or remove power to the phone while it is checking or installing firmware.
You can restart your phone using the IP phone UI or the Aastra Web
UI.:
IP Phone UI
1.Press %on the phone to enter the Options List.
2.Select Phone Status.
3.Select Restart Phone.
4.Press Restart to restart the phone.
Note: To cancel without restarting the phone, press Cancel.:
Aastra Web UI
1.Click on Operation->Reset.
2.Click 
.
3.Click OK at the confirmation prompt.
Getting Started
4480i IP Phone User Guide