Andrew Rossmann wrote:
says...
I know how close captioning is done,
but why does some networks (meaning
CBS)has such bad captioning where
words are dropped and letters are
replaced by funny symbols?

CC (and other data like TEXT and XDS) information is encoded just
above the very top of the picture. Sometimes, especially with HD TV's,
you might see it as some thin lines moving around side to side. Any
noise or distortion up there can scramble the CC.

I have a two-year-old Toshiba 32A62 that gets scrambled data on ONLY
ONE channel, cable channel A&E. A cheap Symphonic next to it, working
from the same RF feed, gets perfect CC data on that same channel. On
all other channels, when there's any garbling both sets will show
identical garbling. So I have my doubts about the implementation of
CC on some sets.

CC can be very amusing! Commercials that say (repeatedly refreshed),
"Sample caption data goes here". Program edits in commercials that
retain parts of the CC from the program, parts that combine in odd
ways. And it's especially fun when one commercial ends with some
blurb that stays through most of the following commercial and seems
to make fun of it (the data will sit there about twenty seconds if
there's no signal to clear it or supersede it).

--
If John McCain gets the 2008 Republican Presidential nomination,
my vote for President will be a write-in for Jiang Zemin.