Allied Telesis AT-S39 - Manual (Page 228)

Section II: Local and Telnet Management
228
The download begins. If you are downloading a configuration
file, the switch automatically resets once the download is
complete. Some network traffic may be lost during the system
reset.
Caution
When downloading a switch image file, the switch must initialize it
by decompressing it and writing it to flash. This requires one to two
minutes to complete. Do not reset or power off the unit while it is
decompressing the file.
The completion of the download and initialization process of
an AT-S39 image file is signalled with this message:
Please press <ENTER> key TWICE to proceed with
Switch Reboot...
h. Press the Return key twice to reset the switch. Some network
traffic may be lost during the system reset.
The download process is complete once the switch has
completed its reset. The new AT-S39 image file or
configuration file is now active on the switch.
i. To continue managing the switch, you must reestablish your
management session.