No, it's not, because calling someones phone is also culturally dependent. Because in Germany, when you are calling someone, it is expected that person picking

No, it's not, because calling someones phone is also culturally dependent. Because in Germany, when you are calling someone, it is expected that person picking up the call will speak up first and introduce themself. Something like: "Herr Mustermann, hallo!". You see, if you are calling person from Germany, knowing how to address him is not enough, you shall still know how to make a call. If you don't know that, you'll be rude anyways, and if you know that, you'll also know a proper way of addressing persons in different cultures.