Page "SECAM" Paragraph 33

These signals are much more important to compatibility than the color sub carriers are.

They differ by AM or FM sound modulation, signal polarization, relative frequencies within the channel, bandwidth, etc.

For example, a PAL D / K TV set will be able to receive a SECAM D / K signal ( although in black and white ), while it will not be able to decode the sound of a PAL B / G signal.

So even before SECAM came to Eastern European countries, most viewers ( other than those in East Germany and Yugoslavia ) could not have received Western programs.

This, along with language issues, meant that in most countries monochrome-only reception did not pose a significant problem for the authorities.