username password
aaa authentication enable console LOCAL
Instead of 'enable' you can also use ‘ssh’, ‘serial’ or ‘telnet’ to change the type of prompt and number of retries allowed.
enable
3 tries before you see "Access denied."
ssh
3 tries before "Rejected by Server."
serial
prompted continually until successful
telnet
prompted continually until successful
More info at: http://www.cisco.com/en/US/products/sw/secursw/ps2120/products_command_reference_chapter09186a008042d6ea.html#wp1025384
