For Fusion customers served out of the two Santa Rosa central offices (COs), we now support Annex M ADSL2+ profiles, in addition to the standard Annex A. Switching to Annex M can provide higher upstream speeds of up to 2.5Mbps per pair, though generally at the expense of some amount of downstream.
The Annex M profile option is in beta test, and the capability may come and go as we wrap up the deployment, so please do not rely upon it at this time. Your loop may not perform better with Annex M than with the standard Annex A profile. We encourage you to experiment and select the profile that you prefer for stability and speed. Loops which prove not to work well with Annex M cannot be “fixed” to do so, and an Annex A profile should be your expectation if the loop is unreliable with a Annex M profile. Loop performance is influenced by many factors.
Due to the decrease in downstream speed associated with switching from the Annex A profile to the Annex M profile, we anticipate that it will be something users may wish to turn on and off as needed, for example before a really large upload or off-site backup. Today, our customer support group can turn on Annex M in the network, and then you can enable and disable it in your modem in order to turn on and off the Annex M support. In future, we anticipate releasing a member tool that will allow you to toggle the setting in our network, allowing you to avoid changing your modem settings locally each time.
For more information on Annex M and details on how you can enable it, see the Annex M FAQ.
Annex M support will be coming to our other central offices in the near future.
For those interested in details about the technology, you can read more on Wikipedia about Annex M, and about ADSL2+.