The time in milliseconds that is waited for a key code or mapped key sequence to complete. Also used for CTRL-\ CTRL-N and CTRL-\ CTRL-G when part of a command has been typed. Normally only 'timeoutlen' is used and 'ttimeoutlen' is -1. When a different timeout value for key codes is desired set 'ttimeoutlen' to a non-negative number.

    ttimeoutlen     mapping delay      key code delay
       < 0          'timeoutlen'       'timeoutlen'
      >= 0          'timeoutlen'       'ttimeoutlen'

The timeout only happens when the 'timeout' and 'ttimeout' options tell so. A useful setting would be

:set timeout timeoutlen=3000 ttimeoutlen=100

(time out on mapping after three seconds, time out on key codes after a tenth of a second).

(default -1, set to 100 in defaults.vim)