Can someone tell me what comdex is? Is this concept
associated only with Las Vegas provider?

LOL!  Comdex is a huge computer industry trade show that has been happening twice a year for many years.  The fall show is always in Las Vegas and the spring show has been in Chicago and Atlanta (and maybe elsewhere.  If you think about what the internet has done for providers and hobbying, maybe you could make the association you suggest, but it would be a real stretch!