In reply to a post by longedge:

In reply to a post by j0hn83:

Openreach simply can't stop you adjusting the downstream SNRM target at the modem.

It's negotiated between the modem and the cab during sync i.e. both 'agreeing' on a figure isn't it?

Upstream SNRM target is set at the DSLAM, downstream is set at the modem.

The DLM tells the DSLAM what both should be, the DSLAM sets the upstream target then tells the modem what the downstream SNRM target should be.

That's why some modems can manually set/override the downstream SNRM target but none can tweak the upstream.