Cortelco 2757 - Manual (Page 58)

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2. Enter the upgrade server (TFTP or FTP) address. Select the server type (TFTP or FTP).
Enter the upgrade filename, username, and password on this page. Note that TFTP does
not require a username or password. Then press ‘SAVE’.
After the information is saved, press ‘UPGRADE’, the IP Phone will connect to the upgrade
server and start to download firmware. This will take several minutes. After the download
is complete, the 2757 will reboot, and then will be ready for use with the new firmware.
5.2 Recover from Unsuccessful Firmware Update
If the download fails, the 2757 may malfunction. If this happens, use the following instructions to
restore it to a normal state.
1. Reboot the 2757 per Section 3-10. If that does not work, disconnect the power cord and
reconnect it after 10 seconds.
2. You should see ‘Loading’ on the LCD. Both the ‘headset’ and ‘mute’ key will illuminate for 2
seconds. After this press the ‘*’ key twice, and the original firmware will be recovered.
If this does not solve the problem, please contact your dealer.
WARNING: Do not disconnect power, press any key, take the phone off-hook, or disconnect from
the network during the upgrade procedure. This can cause the downloaded firmware to be
corrupt and the upgrade will fail!