This is just another case of bureaucrats meddling in things they have no understanding of in order to push their own agenda.
Exactly.. what is it with all this Ecodesign rubbish and need to be green. I had a moan on here a while ago that my so called Eco Washing Machine now takes twice as long to do a wash and costs more in electricity as it now has to heat all water from a cold feed. By hey the label says its green and energy efficient and this makes it look good for statistics. But the reality is that it costs me more to heat water for a wash and nevermind that the machine now has to be on twice as long, so its actually far less energy efficient than my old machine.
snrm will be all over the place as crosstalk jumps up and down
This is reminiscent of "cool broadband" which has been discussed a few times previously on here. BT trialled it on adsl2+ a couple of years ago and abandoned it as being impractical as it caused too many problems. One of the interesting threads is this one -
link.
In there there's a link to a document from
Texas Instruments which specifically discusses the issue of "Time Varying Crosstalk" and makes interesting reading. The PDF doesn't copy and paste very well without some editing so have a read of of the information on and around page 8... but this kind of sums it up
The issue of time-varying crosstalk resulting from L2 mode has recently attracted the
attention of DSL standards committees during the discussions for VDSL2. The short
lines, for which VDSL2 is targeted, suffer from strong Far-End-Crosstalk (FEXT). In this
case, the impact of time-varying crosstalk is expected to be
very significant.
For this reason, it was proposed to
completely abandon L2 mode for VDSL2
[4,5,6,7,8,9]. This proposal gained the support of a number of service operators, including SBC, Bell Canada, BT, Qwest, France Telecom, Telecom Italia and TeliaSonera. The ITU Study Group 15 agreed in the October 2004 meeting that an L2 mode shall not be specified for VDSL2
So basically all new modems must be capable of going into this power saving (L2) mode. Because it looks good if they can stamp an energy efficient label on the side of the box.
But in reality, all of the worlds major ISPs and the ITU say its not practical because it causes too many issues with crosstalk.
What a total waste of time and money by some bureaucratic green department.