What are ADSL2 and ADSL 2+?
ADSL2 and ADSL2+ are further developments of the ADSL standard (defined in ITU-T recommendations G.992.1 and G.992.2). In particular, the developments increase the bitrates and line lengths possible with ADSL. The higher bitrates are intended to allow new applications over DSL, such as HDTV (high definition television).
The maximum bitrate of an ADSL2 line (defined by ITU-T recommendation G.992.3) is 12 Mbit/s. The maximum bitrate of ADSL2+ (defined in ITU-T recommendation G.992.5) is 25 Mbit/s. In addition, there is a variation of ADSL2/2+ which allows an upstream bitrate of up to 3.5 Mbit/s