High-Speed Circuit-Switched Data (HSCSD), is a development of Circuit Switched Data (CSD), the original data transmission mechanism of the GSM network. HSCSD uses different coding methods and even multiple time slots to increase data throughput. It allows maximum transfer rates (using four time slots) up to 57.6 kbit/s and, even in the bad radio conditions will still lead to a four times speed increase over CSD.
