Circuit Switched Data (CSD) Support
- permitting the related bearer types on the 04.08 CC side
- configuring the DSP correctly to perform the 45.003 interleaving / coding for the respective bearer type
- implementing the various rate adaptation functions to get to the individual sync/async characters. AFAIR there even was a hardware accelerator (maybe that was only MTK, not TI?). In any case, we want a software implementation on the host PC side, we don't care about an efficient implementation on the baseband chip.
Test/development could be done against Racal 6103, which supports both data + fax calls
configuring the DSP correctly to perform the 45.003 interleaving / coding for the respective bearer type
JFYI, here is an extract from include/calypso/l1_environment.h:
/* Channel mode definitions for DEDICATED mode */ #define SIG_ONLY_MODE 0 // signalling only #define TCH_FS_MODE 1 // speech full rate #define TCH_HS_MODE 2 // speech half rate #define TCH_96_MODE 3 // data 9,6 kb/s #define TCH_48F_MODE 4 // data 4,8 kb/s full rate #define TCH_48H_MODE 5 // data 4,8 kb/s half rate #define TCH_24F_MODE 6 // data 2,4 kb/s full rate #define TCH_24H_MODE 7 // data 2,4 kb/s half rate #define TCH_EFR_MODE 8 // enhanced full rate #define TCH_144_MODE 9 // data 14,4 kb/s half rate