Again Thanks for your time and report

Looks like you are with TalkTalk? They are mainly with INFN
If yes can you give help here, how to connect? Are the same menus/tabs/settings & chipsets with the 2860
http://www.forum.draytek.co.uk/viewtopic.php?f=2&t=19902
Thanks

No, I'm with BT Infinity 1 for Business.

3.7.8 now on UK site with yet another modem code

Firmware 3.7.8 (for ADSL users) / v2860_378_ADSL
Is identical to "STD" on Draytek FTP site.

Firmware 3.7.8 (for VDSL users) / v2860_378_VDSL
Is identical to "VECTOR1" on Draytek FTP site.

Release notes for STD firmware say to use Modem Code 548006_A
Yet STD firmware also includes a newer modem code 560816 which can be chosen - which works fine for me on ADSL2+ IFTN exchange (TT).

More confusions!

Well I'm on VDSL2 with IFTN DSLAM and the VDSL Firmware is NOT best for me.

Just tried it and it reintroduced sawtooth effect and also interleaving went to 1

I put the ADSL firmware back on with modem code 548006, and everything good. Faster sync, better PSD and interleave 0

Maybe the VDSL firmware is recommended for Broadcom DSLAM but certainly not IFTN.

Thanks for your feedback

This is somewhat frustrating that they are effectively recommending stuff which might not be the best.

Maybe time to fire off an email to support asking for a proper answer to all of this stuff.