I've been on 2 such interviews, and both of them were quite different. At the first one, which was for the university police, they mostly asked me about my experience, and gave me a few situational questions, like "you're working by yourself and you receive a call about a man having a heart attack. At the same time, you also receive a radio call from an officer who is being shot at. What do you do?" A few minutes before this interview began, they provided me with a list of the questions they were going to ask. It was mostly questions regarding my resume and experience though.

On the second one, which was for the county police department, it was ALL listening questions. During one part, they would play a recording of a phone call and then ask me questions about the call. They would also read through some situations and ask which one should be dealt with first, would you have anyone dispatched at all, etc. For this one they didn't allow note-taking, and I didn't know what to expect beforehand like I did with the first one. They also did not ask me anything about my experience, it was purely a skills test.

Unfortunately, I can't tell you what kind of interview to expect because it could be either of these, or neither. I went into the second one expecting it to be more like the first one, where they'd ask me about myself and why I think I would be great for the job, etc (more like a typical interview) but it wasn't, and to be honest I was not prepared for that. I did alright, I think, but I know that I didn't sound as confident in my answers as I should have.

Just be prepared for anything, is all I can say! And good luck :)

edit: If anyone is wondering the outcomes of the interviews I had, I did pass the first one and was called to go to the next step: background check! However, in the 6 months it took going through the process up until that point, I had already found another job that I'm quite happy in.