Certification

[dhouston]

Unless you are using wireless, there's little need to worry. Most wall transformers, etc. have UL/CE labels. I really don't understand you question as regards USB.

I already gave you a link to FCC Part 15 in another thread. Canada follows pretty much the same rules.

Europe allows far more transmit power but has stricter rules on frequency tolerances. Australia allows even more transmit power than Europe. Of course, much depends on specific applications, frequencies, etc. I'm generalizing about the ISM bands.

All transmitters require testing at FCC approved labs (probably owned by FCC commissioner relatives?) and fees are very high. Superhet receivers can be self-tested/certified but you are supposed to maintain records and the test equipment cost will tell you why the commissioners' relatives charge so much.

Radiometrix in the UK has links to rules for many countries on their website. They used to have a chart showing differences in transmit power but I'll have to check my notes for the URL.