G.992.3

Asymmetric Digital Subscriber Line 2 ( ADSL2 ) and extended bandwidth Asymmetric Digital Subscriber Line 2 ( ADSL2 ) are further developments of the ADSL standard ( G.992.1/G.992.2 ), which above all improve data rates and range of an ADSL connection. The increased range allows the network operators to offer ADSL to a larger number of potential customers, while enabling higher data rates, new services such as high definition television ( HDTV) over an Internet connection.

ADSL2 and ADSL2 have been standardized as G.992.3 and G.992.5 from the ITU.

Differences to ADSL

The maximum downstream data rate of ADSL2 is 12 Mbit / s in comparison to max. 8 Mbit / s ADSL; an improved signal processing and coding results in higher data rates for a given relative distance.

ADSL2 extends the bandwidth of the ADSL signal from 1.1 MHz to 2.2 MHz, thus increasing the maximum data rate to 24 Mbit / s in the receive direction ( in Germany, with the exception of some locally available offers only max. 16 Mbit / s in receiving direction offered ). ADSL2 / 2 also features a power saving function ( L2 mode ) when no data is transmitted, as well as the so-called Seamless Rate Adaptation. This power saving function may not be available at Annex- J connectors. Both features were still unused in most ADSL2 providers in Germany in summer 2009.

Compatibility with ADSL

During the construction of an ADSL2 / 2 connection modem and switch exchange information on the capabilities of the other side, so usually can both ADSL2 / 2 modems in a pure ADSL network and the ADSL modem to an ADSL2 / 2 line can be operated ( although the latter does not apply to ADSL2 ports of Deutsche Telekom).

ADSL2 / 2 variants

With Reach Extended ADSL2 (RE- ADSL2, ITU G.992.3 Annex L ) transfer variant for very long connecting lines was standardized as possibility analog telephony, is in the raised in the lower frequency ranges, the transmission level, bringing the suppliable with an ADSL central office face opposite to ADSL over POTS (Annex A ) is increased by about 40%. France Telecom is RE- ADSL2 since spring 2006 nationwide for long connecting lines a.

• Analog / ISDN
• Protective tape
• Upstream
• Downstream ADSL/ADSL2
• Additional downstream ADSL2

In order to meet companies that have a higher outgoing data traffic than average consumers usually were with ITU G.992.3 / 5 Annex M ( with possible simultaneous analog telephony ) and ITU G.992.3 / 5 Annex J ( for unbundled DSL) variants of ADSL2 / 2 standards created, the maximum data rate in the send direction (ie the network) to up to 3.5 Mbit / s increase. These variants have, because of the identical up / downstream frequency split at 276 kHz high Spektralkompatibilität to the previously used exclusively in Germany ADSL-over- ISDN (Annex B ), which is why they for Deutsche Telekom in contrast to Annex A and Annex L of Use are released in their local loop network for several years; nevertheless, there was the summer of 2009 no offers based on it on the German market. At Deutsche Telekom has been considered in the future to use at All - IP ports Annex J replace Annex B. In the meantime (as of November 2011) there are already over Annex- J realized ports that also do without forced separation. Outside Germany, the Annex M based DSL access, however, for several years, for example, the Australian provider Internode, (20 Mbit / s downstream, 3 Mbit / s upstream) offered by the British operator Be *, the Danish provider full-rate and the Swedish supplier Bredbandsbolaget.

In Japan, a further, previously standardized version of ADSL2 is used which extends the reception range to 3.7 MHz and allows data rates up to 50 Mbit / s. With these high data rates ADSL competes with VDSL, with the advantage, even at large distances of the participant from the exchange to be able to connect.

The bundling of several copper pairs by bonding DSL- level protocol to increase the data rates possible - In addition, in ADSL2 / 2 - as before only with SDSL.

ADSL2 as a prerequisite for IPTV

With over ADSL2 feasible data rates simultaneously multiple HD / SD IPTV channels can be transmitted simultaneously while still leaving data rates are reserves for the internet surfing and VoIP available, which is a prerequisite for the commercial IPTV marketing. In addition to providers such as Telefónica Germany (formerly HanseNet ), the planned their IPTV service from the start on ADSL2, the German Telekom offers since late summer 2007 after it has built in 750 cities a parallel streaming -capable IP - concentration network, you originally only Configured for VDSL2 Triple Play / IPTV offering Telekom Entertain also on ADSL2 .