There seems to have been a lot of discussion across various forums regarding BT rolling out G.INP, so thought I'd share my experience:

I am located very close to my FTTC cabinet and up until mid-March used to sync absolutely reliably at 79995/19995 kb/s with approx 9mS ping (as measured by thinkbroadband quality monitor). Suddenly the downstream dropped to around 65Mb/s with pings increasing substantially to ~30mS. I'm supposing this is the effect of G.INP being activated with incompatible modem firmware?

Anyway I have today upgraded to firmware 3.7.8.1 Vector2 which has almost got me back to where I used to be (Vector1 offered no improvement to sync speed), currently syncing at 75771 kb/s downstream which I suppose is close enough and pings are back to previous levels...

Anyone know how I can conclusively tell whether G.INP is activated and whether 3.7.8.1 is supporting it in an optimal fashion?

Chris

So to follow up on this, I have just changed the modem code [WAN>General Setup>DSL Modem Code] to the other available option - so from AnnexA_571a17_570111 to AnnexA_572d07_570e01. This has restored my line speed to the full 80/20 whilst keeping pings at around 10mS [it looks like the downstream SNR margin is now optimised compared to previously - so now 9dB, was 10dB with reduced throughput]. I notice that this DSL code also now correctly shows the upstream speed (I think there may be a bug in the _570111 version since the reported line speed clearly has too many digits).

There are too many unknowns to play with - 3 different software versions of firmware 3.7.8.1 presumably each with 2 DSL modem code options - that's 6 different configs to try! An official statement on what each is intended to do would be really useful.

Hi, I had a similar issue in that when upgrading to the standard firmware or vector1 firmware I had reduced line speeds and silly attenuation figured. It's worth mentioning I use ADSL2+ not VDSL.

Switched to vector2 with the 570E01_A and everything is back to normal. Seems to be definite changes since 3.7.8 which are not documented in the change log.

Hi,
I've had a similar speed drop from 79 to 64Mb/s and increased latency since a couple of weeks ago.
Today I've upgraded my router from a 2850 to a 2860, installed 3.7.8.1 vector2 and selected the AnnexA_572d07_570e01 modem code.
Happily back to my original speed and latency thanks to this forum.

Steve

This are good news, seems vector 2 modem code 570e01, is a successful one