There is an initial phone interview with HR where they gather general info about you: salary expectations, what you are currently doing, etc. Later there is a second interview at the company with the person who will be your manager and depending on the level of the position more people can be part of the interview. So for example, if you are a level one engineer, maybe you are only interviewed by the Project Manager, but a QA Manager maybe interviewed by the HR Manager, QA Director and Production Manager or even the General Manager depending on the exposure of the role.