Them little dots in the corner of the screen just before the adverts come on
 

In article ,
Edster wrote:
I always assumed, rightly or wrongly, that they were there to tell
someone to get ready to put the tape in with all the adverts on. Like
similar blobs in films that told projectionists to get the next reel
ready in old style cinemas. But I somehow doubt that TV companies work
that way any more, and are more likely to use computers than people to
do that sort of thing.

Not many programmes have the little dots any more, but a few of them
still do. Afterlife had them, for example. Is there any advantage to
them any more? Are they there for the benefit of foreign
transmissions, or are they just included because they always used to
be there? Or is there still someone sat there waiting for the ad break
who needs to push a button when the little dots come on?

Not to "get ready to put the tape in", but get ready to run it. The old
BBC timings we 1 minute to go (approx) - on; 10 secs to go: off; 5 secs
to go; on.

They tended to get used for cueing live programmes, particularly those
originating from outside broadcasts. These cues could be seen on any
"off-air" picture and cut down on the need to rent extra communication
circuits.

The same logic could easily apply to adverts.

--
From KT24 - in "Leafy Surrey"

Using a RISC OS computer running v5.11