G.992.5 Annex M

Annex M is an optional specification in ITU-T recommendations G.992.3 (ADSL2) and G.992.5 (ADSL2+), also referred to as ADSL2 M and ADSL2+ M. This specification extends the capability of commonly deployed Annex A by more than doubling the number of upstream bits. The data rates can be as high as 12 or 24 Mbit/s downstream and 3 Mbit/s upstream depending on the distance from the DSLAM to the customer's premises.

The main difference between this specification and Annex A is that the upstream/downstream frequency split has been shifted from 138 kHz up to 276 kHz (as in Annex J), allowing upstream bandwidth to be increased from 1.4 Mbit/s to 3.3 Mbit/s, with a corresponding decrease in download bandwidth.

Deployment

Santa Rosa, California-based US ISP Sonic.net is now testing Annex M on both single-pair and pair-bonded "Fusion" ADSL2+ service. The company reports that customers can see 1.3-2.5 Mbit/s upstream per pair with Annex M enabled.

This standard was approved for deployment on Australian networks by the Australian Communications Industry Forum (ACIF), due to action by Internode. iiNet now offer Annex M on their business plans for a one-time additional fee.

The Danish ISPs Fullrate, Telenor and TDC offers up to 2 Mbit upload using this technology.

Since October 2006, the Swedish ISP Bredbandsbolaget offers a service called "Bredband 20 Pro" with 20 MBit/s down, 3 Mbit/s up. However, media has lately reported that a majority of their customers fail to get their modems to sync with Bredbandsbolaget's Annex M gateways faster than 16 MBit/s down and 2.5 MBit/s up .

The Swedish ISP Telia has offered Annex M on their ADSL2+ 24Mbit connections since October 2006.

The Finnish ISP SuomiCom offers 4/3 Mbit, 8/3 Mbit, 12/3 Mbit and 24/3 Mbit on ZyXEL's Annex M hardware. Usually upstream speeds between 2-2.5 Mbit/s are reported with these services. ISP Nebula also offers Annex M on some of their more expensive packages. 8 Mbit/s or 24Mbit/s down and 3 Mbit/s up.

The Belgian ISP Dommel(Schedom) Recently offers ADSL2+ Annex M (24Mbit/s down and 3 Mbit/s up) in their "cityconnect" package in the city of Leuven (on their own DSLAMs). Two other cities have been announced for the second quarter of 2008, Kessel-Lo (near Leuven) and Sint-Truiden. Now it is available in and around various large cities and city centers.

The British LLU ISP Be Un Limited offers a feature on their "pro" package called "Upload Plus". This is actioned from a support ticket and changes the customers connection from ADSL2+ Annex A to ADSL2+ Annex M. "Pro" users get Annex M by default. Other British ISPs, Nildram, Pipex (both owned by TalkTalk), Cambridge Matrix and Claranet have recently started offering enhanced upstream to their customers. Claranet refer to their Annex M product as 'Premium SDSL'.

The Spanish ISP Jazztel implemented Annex M in January 2009, with a feature called "Turbo Up" and "Turbo Down" that allows the user to choose between a higher upstream or downstream speed, plus an option to enable or disable FastPath on demand. In most cases it's imposible to achieve more than 1.5 Mbit/s upstream with the ISP provisioned CPE, with better equipment it's possible to reach 2.5 Mbit/s upstream.

See also

• ADSL2
• ADSL2+

External links

• ITU-T Recommendation G.992.3 : Asymmetric digital subscriber line transceivers 2 (ADSL2)
• ITU-T Recommendation G.992.5: Asymmetric Digital SubscriberLine (ADSL) transceivers - Extended bandwidth ADSL2 (ADSL2+)
• ITU-T Recommendations: Series G
• ITU-T
• Internode ADSL2+ Annex M FAQ
• UK ADSL2+M ISP be
• UK ADSL2+ and Annex M Service Provider Claranet