Only if you really, really need to.
Prof. Itoh: 6533 (Room 7-13)
Prof. Rzepka: 6535 (Room 7-14)
Students room: 7389 (Room 7-08)
Country code: +81
City code: 011 (remove zero when adding to the country code)
University code: 706 (then add the extension number from the list above)