Even within Austria there are differences: i used to live in Innsbruck with an address written 4-51 (meaning street number 4, door 51) and then moved to Vienna, street number 2, door number 14. But in Vienna 2-14 means the big building with street numbers 2 through 14. My building was not big, you could physically see it is street number 2. Well, i never got that letter.
>>Comput+nk1
2/14 is the correct way, but if number 2 has several staircases (typically the case of a 2-14) it would be 2/3/14 (or typically 2-14/3/14) with 3 being the staircase number