Why did old TVs require that the channel be on 3 before accessories like VCRs and game consoles could work on them?

Question

Anyone who grew up in the CRT era of TVs remembers that you had to turn the channel to 3 before you turned on the VCR or game console. Otherwise, the picture would not work. Why was this so necessary?

Edit: woah this blew up while I wasn’t looking! Thanks for the replies!

In: Technology

Answer 1

Older TV sets did not have inputs for devices. They could only display pictures that came in as TV signals. So the devices had to emit a TV signal.

TV signals have to be on some channel. By convention channel 3 was used (only a few areas had a Channel 3 station).