This O'Reilly post notes several nice bits of the history of the AP, a useful topic for anyone interested in media or information history.
First comes the 1850s creation of the enterprise, including some practical collaboration to share news.
Next is a brief note on the teletype. I appreciate the section on teletypespeak:
"--30--" meant "end of story" or "end of transmission." It's a convention that many writers continue to use today. "--73--" meant "thanks" and "--88--" stood for "love and kisses." Add telex jargon to the odd history of abbreviated communication that today includes emoticons and SMS acronyms.