2G denotes second generation mobile telephony systems. 2G systems were first to use digital encoding technologies. Among 2G systems are: GSM, D-AMPS (TDMA) and CDMA. 2G networks are nowadays (year 2003) the most spread kind of cellular telephony systems in use. 2G networks feature good quality voice (itīs digital!) and low-speed data transmission (either CSD or GPRS). Part of 2G networks are auxiliary services that include SMA, fax and data. Transmission in 2G systems is not only digital but also encrypted, so no longer overhearing is possible.
