If someone's phone has a busy signal and it's real fast busy signal, and it doesn't sound like?

a usual busy signal sound, . . . . . And it is always . .always busy . . what does this mean? Is it disconnected? Is it set up so can't receive MY call only? Or just any call from OUT OF STATE? What's up. Can't call operator . . .cause my phone says I don't have this service . . .and I think most the time they don't know anyway. And my cell phone won't tell me cause it too 'doesn't have this service'.