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 home.

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

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 ISP Fullrate has also begun to deploy this technology to offer up to 2Mbit upload. Another Danish ISP, Cybercity, is working on a general offering for Q3 2007 for customers placed close enough to their base stations. Same goes for Danish TDC which have completed their deployment.

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

The Belgian ISP Dommel(Schedom) Recently offers ADSL2+ Annex M (24Mbit/s down and 3Mbit/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 Tiscali) 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 1Mbit/s upstream with the ISP provisioned CPE, with better equipment it's possible to reach 2,5Mbit/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