This TS contains the stage 2 service description for a High Speed Circuit Switched Data (HSCSD) on
GSM/GERAN in A/Gb mode and Iu mode. HSCSD utilizes the multislot mechanism, i.e. using multiple traffic
channels (/bearers) for the communication.
Additionally, the present document specifies some HSCSD related requirements for multi system mobile stations
operating in UTRAN Iu mode. In UTRAN Iu mode one bearer can provide all needed data rates, and the multislot
mechanism is therefore not needed. However, for inter-system handover to GERAN, certain information has to be
provided by the mobile station during the service negotiation. The UTRAN Iu mode aspects concerning HSCSD are
described exclusively in clause 4.2.