GSM (Global System for Mobile Communication) is a standard that is available almost everywhere for mobile radio equipment (mobile phones, cellular phones). In Germany,Mannesmann (D2 privat) Deutsche Telekom (D1 Telekom) made available this network.

You can call in over 50 countries worldwide and talks with other network companies are under way. If your the proud owner of a mobile phone, then you can expect to be able to call from almost everywhere in Germany. The reason for the 'almost' is that it is as yet not possible to lay out a digital radio network without reception holes.This means that there are places in Germany where your GSM mobile phone will not receive any signals.

What will calling on the GSM network cost me? A mobile phone is cheapest if you sign an agreement (card agreement) for the use of the network (as with Debitel). The advantag eof that is that a part of the commision the dealer charges you when signing a card agreement is credited towards the cost of the telephone. If you're lucky you can get hold of a mobile phone for as little as DM 1,-

If you don't want to pay much for the fixed monthly charge, then fairly lucrative agreements (fixed charge approx. DM 25,-) are to be found provided you sign up for a minimum of two years. The problem is that calls to the public service telephone network are costly, or at least during the day. These calls can cost up to 1,70 DM per minute. If you opt to pay a higher fixed charge then this will probably soon add up considering that calls will cost you only about DM 1,30 per minute.

Summary
If you don't call a lot or only in the evenings and only need to be 'reachable', then best bet is to pay the lower fixed rate and thus the higher minute-rate for a call. If you make more frequent calls, use the phone during the day, and want to be available, you're best off paying a higher monthly charge and pay less for a call.

Using your mobile abroad? The good thing about the GSM network (D-Netz or networkis that you can call when you're abroad, eg you can be reached on your mobile phone whilst on holiday in the Canary Islands.
Beware: If your abroad when somebody calls you will have to pay part of the call charge! The caller is only charged for the connection to the German border and you will be charged for the rest. This is because the caller cannot know that you're spending time abroad. That is why you have to carry the cost.