Annex M FAQ
ADSL2 offers a variety of configuration profiles that allow for changes to the speed and settings of the circuit. The default configuration is Annex A, which provides a maximum speed of 24Mbps download, and 1.4Mbps upload. (We market these speeds at 20Mbps and 1Mbps, as full ADSL2+ speed is rare, limited to very short loops.) Annex M changes the allocation of spectrum, allowing a maximum 3.3Mbps upload speed.
Annex M comes at a cost of reduction in actual download speed for most customer locations, so while you may gain a megabit or so in upload speed, the trade-off in reduction of download speed may be significant. Consider your own bandwidth needs and make a selection based upon your preferences.
For more details on Annex M, see Wikipedia.
The choice of Annex A or Annex M profile is available to Sonic.net Fusion customers at no additional charge.
Most modems support Annex M by default, but for some older modems you may need to configure your ADSL2 modem to allow an Annex M connection. For assistance please see the forums