Samsung UN46ES6500G E-Manual page 32

Lock a channel so that the channel
cannot be selected and viewed.
N
This function is available only when
the
●
Rename Channel
(Appears only if you have selected an
analog channel.)
Lets you assign a name of up to five
characters to an analog channel. For
example, Food, Golf, etc. This makes it
easier to find and select a channel.
Channel Lock is set to On.