Aastra Telecom 53i IP Phone - Manual (Page 13)

Model 53i IP Phone User Guide 7
Getting Started
If changes have been made to your phone settings, you may need to restart
your phone. For more information on restarting your phone, see
"Restarting your phone" on page 39 .
For more information about connecting your phone, refer to the Aastra 53i
Installation Guide under the section "Connecting to the Network and to
Power". Check with your system administrator for assistance.