How HTTP servers accepts Telnet

I understand that Telnet is a protocol as much as HTTP. I have this notion that after the initial TCP connection is made the Telnet client would send some telnet specific code over to the server on the other side in this case a HTTP server. But since HTTP server doesn't understand Telnet specific codes it should throw an error or drop the connection etc. But in reality we can telnet to a HTTP server and fetch pages if we type in correct HTTP headers and send them. How can it be like that? Wikipedia entry really didn't help me to understand this specific point. (http://en.wikipedia.org/wiki/Telnet#Telnet_data)