GSM services
GSM has basic services that are divided into teleservices and bearer services. Teleservices support all functions of the layer model and offer high compatibility with all fixed network services.
The teleservices include telephony, short message service( SMS), multimedia message service( MMS), fax and Btx. The carrier services support transport-relevant functions such as synchronous and asynchronous data transmission at various speeds.
Data services are concerned with mobile data. These services include e-mail, file transfer or integration into online services. Thanks to the digital transmission of user data, a data rate of 9.6 kbit/s is achieved during data transmission, with a bit error rate of 2% in the peripheral areas of the cells. For both basic services, there is a wide range of additional services, such as call forwarding( CF, CFB, CFU), caller ID, call waiting, call barring, call charge services, closed user group(GBG) or conference calling.
In addition to the aforementioned services, there is also an IP-based direct call service with push-to-talk ( PoC) operation, which is supported by General Packet Radio Service( GPRS).