Why do some cable stations emit what sounds like touch tone phone sounds from time to time? It’s usually four tones in rapid succession. What’s this all about?
Most cable feeds come through various local repeaters. Each fo these mini TV-stations can have a rack of VCRs so that your local cable company can sll local advertizing time (“Come to Honest Al’s – the best Used Cars in Posthole, Michigan”).
The tone signals the repeater to run the local content (if there is some). There’s another tone at the end of the commercial break (which you don’t here because the local ads are running) which switches everything back to the global feed.
That’s why you’ll sometimes see half-a-second or so of some National ad (“Miss Cleo, your Psychic Friend”) at the very end of a commercial break.
ScruffThat’s odd…the cable I subscribe to has those half-a-second or so ads at the very beginning of the commercial break!