In alt.home.repair, on Fri, 9 Oct 2015 08:50:12 -0700 (PDT), trader_4
wrote:

On Friday, October 9, 2015 at 11:27:00 AM UTC-4, Mark Lloyd wrote:
On 10/08/2015 01:40 PM, micky wrote:

[snip]

"This program has been brought to you in compatible color"

which I didn't understand for another 30 years. Compatible meaning
black & white sets could understand it and show the picture in black and
white, and the opposite too, which iirc meant when they sent a black and
white show in compatible color, the color sets would render it in black
and white.

I almost said it right. Compatible color meant that the signal of a
color program could be understood by black & white sets and shown in
black and white , and that the signal of a black & white program could
be understood by a color set and displayed in black & white.

When parts of the world, probably Europe, got color tv they didn't have
the enormous number of black & white sets and IIRC they used a different
method for color that wasn't compatible with black & white, but other
than that, it had advantages over the method used for color in the US.

A color TV is capable of displaying a black and white picture. It checks
for the color signal and works in black and white if there is none,
using a circuit which I seem to remember being called a "color killer".

"compatible color" would be needed when an old black and white TV gets a
color signal.

Both of those are part of compatibility.

IDK what "compatible color" means.

Now you probably do.

The color broadcasting system was
designed so that a color broadcast would display as black and white on
the millions of bw sets out there at the time. The color part was
a compatible addition to what was already there.

Yes.