The “Ericsson GSM System” is Ericsson’s implementation of the Global System for Mobile Communications (GSM), encompassing GSM 900, GSM 1800, and also a GSM 1900 standard for the North American market. These systems are built around Ericsson´s AXE switching system technology. AXE’s system modularity standard allows functions to be added, deleted, or modified without disturbing the functionality in the rest of the system. Thus creating an environment where Ericsson’s GSM system can profit fully from future AXE developments