Chapter 1 What’s New for FortiOS 5.0 : New features in FortiOS 5.0 Patch 4 : Configurable idle timeout for console admin login sessions
  
Configurable idle timeout for console admin login sessions
An idle timeout has been added for FortiGate console sessions (admin sessions connecting to a FortiGate console port or USB port). By default the console timeout is set to 0 and console sessions will never timeout. You can enable a timeout in the range of 15-300 seconds from the CLI. Use the following command to set the timeout to 25 seconds:
config sys global
set admin-console-timeout 25
end
Use the following command to disable the timeout.
config sys global
unset admin-console-timeout
end