In some apartments there are fixed landline phones installed, but some may not be set up for international calls, some are even limited to just the city. Ask the landlord to expand the service if you need it. For international call purchase an IP card (sold on campus) and follow the instructions. Much cheaper of course are Skype or other VOIP calls.
You can always be reached from Europe even on the limited phones, which is much cheaper for you then being called on the mobile phone.