Sony Trinitron KV-20TS27 Operating Instructions Manual page 15

Press the channel number button(s) and then press ENTER
to select the channel you want to add or erase.
Mom
2 To add channels - Press ADD.
ADD
A "+" appears before the number for a moment.
This channel has now been added to the channel scan memory.
To erase channels — Press ERASE.
A"-" appears before the number for a moment.
RM-783 This channel has now been erased from the channel scan memory.
The next time the CH +/- button is pressed, this channel will be
skipped.
Repeat steps 1 and 2 to add or erase other channels.
CAUTION Cable TV channel chart*
Note
Pay cable TV systems use scrambled or encoded signals
and require special converters (decoders) in addition to the
normal cable connection.