The interview process is quite long, it consists of several steps:
1. Telephone talk with HR colleague
2. Telephone interview with basic technical questions
3. Half-day interview with several teams - mainly technical questions
4. Telephone interview with a New York colleague - I could barely hear the voice of the other man
5. Telephone talk with HR colleague, speaking about the offer
Decent English is a must. The interviewers were correct and nice.