When you walk in, you'll be greeted by a very nice receptionists who will ask you to have a seat. You will wait to be seen, as the interview panel may be busy with another candidate. You will be called back.
More than likely, your interview will consists of a panel of people: The Police Commission, The Chief of Police, Dispatch Supervisor, and that person's assistant. This sounds daunting, but it's not. Everyone there is very excited to see you and want to learn more about you.
The interview is pretty standard with basic questions. They may or may not be looking for skills that are related to multi-tasking, and your general ability to deal with the public.
Other things to consider is that, if hired, you will be subjected to a hearing test, drug test, and typing test. This is to peg your ability to succeed in this career,