G.992.5 Annex M

From Wikipedia, the free encyclopedia
  (Redirected from ITU G.992.5 Annex M)
Jump to navigation Jump to search
Annex M
ADSL modem Huawei MT882.jpg
StatusIn force
Latest version1.2
April 2004
Related standardsG.992.5
LicenseFreely available

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.[1][2]

Frequency plan for common ADSL standards and annexes.
  Guard Band
  Downstream ADSL/ADSL2
  Additional Downstream ADSL2+

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 B/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.


This standard was approved for deployment on Australian networks by the Australian Communications Industry Forum (ACIF).

See also[edit]

External links[edit]


  1. ^ "G.992.3: Asymmetric digital subscriber line transceivers 2 (ADSL2)". www.itu.int. Archived from the original on 2021-06-13. Retrieved 2021-06-13.
  2. ^ "G.992.5: Asymmetric digital subscriber line 2 transceivers (ADSL2)- Extended bandwidth ADSL2 (ADSL2plus)". www.itu.int. Archived from the original on 2021-06-13. Retrieved 2021-06-13.