Done over multiple calls. Two technical and one for human resources. The technical ones where theoretical without questions on my software background. The call with human resources was tailored with the classic HRish questions.

Regular. The first contact is with HR which ask the canonical questions of: why are you interested in the position? what is your expected salary and when can you start. After that there is a follow-up technical interview. If successful HR will contact you to what was for me a non-negotiable offer.