2. The name "TDMA" is also used to refer to a specific second generation mobile phone standard - more properly referred to as IS-136, which uses the TDMA technique to timeshare the bandwidth of the carrier wave. It provides between 3 to 6 times the capacity of its predecessor AMPS, and also improved security and privacy. In the United States, for example, AT&T Wireless uses the IS-136 TDMA standard. Prior to the introduction of IS-136, there was another TDMA North American digital cellular standard called IS-54(which was also referred to just as "TDMA").
The two different uses of this term can be confusing. TDMA (the technique) is used in the GSM standard. However, TDMA (the standard) has been competing against GSM and systems based on CDMA modulation for adoption by the carriers.