Samsung PN51E6500EFXZA - Manual (Page 143)

Security Key or a WPS PIN using the
keyboard on the Enter security key
screen.
N To enter letters, highlight and
select each letter. To enter
numbers, highlight and select
each number or press the number
buttons on your remote.
N To shift to capital letters (or from
capital letters to lower case),
select the Caps or Shift button.