.png){kind=link}
 - Vertical.png){kind=link}
.png){kind=link}
 - Vertical.png){kind=link}
.svg){kind=link}
.png){kind=link}
Circuit Switched Data
It was the original data transmission system designed for TDMA mobile networks such as GSM and CDMA.
It was succeeded by High Speed CSD (HSCSD), before being replaced by GPRS, EDGE and UMTS in GSM.
HSCSD was for higher bandwidth in GPRS and EDGE systems, and was more expensive to use.
CDMA used a variant called CDMA CSD for backwards compatibility with the original TIA/EIA IS-95 (cdmaOne).
Enhanced CSD (ECSD) was developed and used alongside HSCSD in GPRS, EDGE and UMTS as a fallback.