ADSL2 is an enhanced ADSL standard, approved by the International Telecommunications Union (ITU) in 2002. It is designed to improve performance and interoperability compared with the original ADSL1 standard with slightly enhanced speed at 12Mbps and longer range.
Interoperability has been improved between different chipset vendors by additions to the training algorithms and initialization procedures.
The available reach is slightly longer than ADSL1 at approximately 600m. It also offers higher speeds, from 8Mbps with ADSL1 to 12Mbps.
Other advantages include better line diagnostics via the modems and power saving modes for modems when they are not transmitting.
Faster startup times have been achieved from 10 seconds for ADSL1 to less than 3 seconds for ADSL2.
ADSL2 also supports bonding of multiple phone lines resulting in double or triple the available bandwidth etc.
Packet-based services such as Ethernet can now be transported over ADSL2 and an optional all digital mode has been included which allows data transmission in the POTS portion of the phone line which adds 256K bit/sec to the upstream data rate.
Due to having the same wavelength (spectral mask) as ADSL1, there is no technical reason why ADSL2 should not be adopted today over existing phone lines.
Most of our modems and routers support ADSL, ADSL2 and ADSL2+, and so are ready to support new faster services as Internet Service Providers (ISPs) introduce them.