Primarily high-quality digital voice calls and SMS.
GSM provides a variety of standard services and built-in security measures: GSM – Architecture, Protocols and Services
Handles the radio link with mobile devices. It includes the Base Transceiver Station (BTS) , which contains the radio transmitters and receivers, and the Base Station Controller (BSC) , which manages radio resources and handovers for multiple BTSs. Primarily high-quality digital voice calls and SMS
Support for data transmission, originally limited to 9.6 kbps but later improved through upgrades like GPRS and EDGE . and the Base Station Controller (BSC)
A permanent database containing subscriber profiles and their last known location.