GSM, a digital mobile telecommunications system has the advantage that far more than the analog systems, among them:
* The capacity of larger systems, because it uses digital technology in which usage of a channel not only for just one user. So when the user does not transmit information, the channel can be used by other users.
* Its as an international standard enables international roaming
* With digital technology, not only to deliver voice, but allows other services such as texts, images and video.
* Security system better
* The sound quality is more clear and sensitive.
* Mobile (can be taken anywhere)
However, the benefits of a diverse GSM proper course makes it the largest mobile telecommunications system users worldwide.
Source : http://id.wikipedia.org/wiki/GSM#Keunggulan_GSM_sebagai_Teknologi_Generasi_Kedua_.282G.29