Unfortunately it's true.
The DLM is BT Wholesale's, and ISPs have no direct control over it. The default is 6dB, and given a period of high stability it drops automatically to 3dB. I don't know how stable it has to be, sorry.
You can get routers where you can adjust it yourself. Common ones you should be able to pick up cheaply are the Netgear 834GT (any version) and the 834Gv4. You have to be careful when "tweaking" in that way on BT Wholesale DLM, as too many reconnections in a short period can screw you up for weeks. Three of four in a hour is as much as I'd try.
More information on Netgear tweaking
. I advise the DMT dropdown menus (where once you create a setting it remembers it in the menu
) or CLI methods. The DGTeam method does allow the setting to be retained through a router power-cycle, but I didn't like it.
My broadband basic info/help site - www.robertos.me.uk
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