When giving out a phone number, what is used for the number 'zero', 'null', or 'zero' or? (In English, 'oh', or 'zero' is used, interchangeably.)

Hi there, when giving out phone numbers you just say "null" as there is only one way to say "zero" in German. It is however very common to say "zwo" instead of "zwei" for "two". The reason for doing so is that "zwei" and "drei" sound reasonably similar when said really quickly. Also if you are giving numbers out over the phone you want to make sure that the person on the other side understands you. So, the number 523768 would be "fünf, zwo, drei, sieben, sechs, acht". Some people also say telephone numbers in pairs. So the above example would be: zweiundfünfzig, siebenunddreizig, achtundsechzig. For a beginner is this certainly a bit harder (as you know the German numbers are kind of backwards) so just ask: Können Sie die Nummern bitte einzeln wiederholen? Could you please repeat the numbers individually? I hope that helps.