I first had a phone call about the usual, personality-screen type of questions which lasted about 30 minutes, mostly about behavioral style questions. It was pretty easy, and just to see whether or not you could be recommended to the hiring manager. The second round was also a phone call, about 30 minutes as well. This had more to do with my own research background, why I felt qualified for the job, and my understanding of the project my interviewer described to me.