I had two phone interviews, the first with the Director of Systems Engineering, the second with some engineer. The first interview was very general. My impression was that he was gauging my interest in the position and company. The second interview was delayed for a few hours for some reason. I called my recruiter to confirm the time, and he touched base with the engineer. We were able to connect and continue later on that evening, which I was a bit surprised, since it was after 7pm EST.