He called 911 - you can see the read out of many of the 911 calls he made.
http://www.sanfordfl.gov/index.html
The call itself is answered, "Sanford Police Department, line is being recorded. This is Sean" who then waits for George to speak. The 911 calls from all the neighbors are answered, "911 - do you need police, fire, or rescue?"
Thanks. The site is very helpful for giving background and texture to the situation.
He did not call 911. That is documented in the call logs at that link, although they were carelessly labeled by the city. It is also stated by police in the very first document at that link.