CSD

CSD (Circuit Switched Data)

CSD allows a user to use their wireless handset as a modem for laptops, PDAs and other electronic devices via infrared ports or designated data cables. CSD also allows a user to access Wireless Internet via their wireless handset (handset must be WAP compatible). (Cingular)

Circuit Switched Data, often referred to as CSD, is the original form of data transmission developed for the TDMA-based mobile phone systems like GSM. CSD uses a single radio time slot to deliver 9.6 Kbits/sec data transmission to the GSM Network and Switching Subsystem where it could be connected through the equivalent of a normal modem to the PSTN allowing direct calls to any dial up service. As of 2006, some GSM-based service providers, Cingular et al, still provide CSD by request.