Sync drops when phone rings (subject was "Is this a record?)

[#1]

I've now found what I think is the definitive statement for the upgrade of this exchange: https://www.btwholesale.com/pages/static/Library/Network_Information/21CN_Broadband_Availibility/ind... - the WBC SFBB Dataset downloaded from here: https://www.btwholesale.com/pages/static/Library/Network_Information/21CN_Broadband_Availibility/ind...
My exchange isn't on the list

[#2]

All-in-all it's obvious you aren't getting the sync speed you should for your line attenuation, it should be 8128 which it does after a line reset, but interleaving is now on, also the fact that a Vendor ID for the DSLAM chipset is not being returned and this coupled with the loss of sync with an incoming call and the fact that there is a shed load of CRC errors at the exchange seems to me to clearly indicate an exchange fault.
IF a TPM has been done and a REAL Lift and Shift, then clearly the Line Card is faulty and Plusnet must pressure BT to fix/replace it.
I said REAL Lift and Shift as I've seen what I regard as abuse of the term recently, that is it means a shift onto a new port not as seems to have been implied in some instances,  just a disconnect and reconnect.

[#3]

I had flagged up to the engineer that the sync was low for the attenuation at the first visit. Using the Kitz tool it predicts up to 29 should get full speed. Certainly I've seen full speed before I moved here on a higher attenuation using the same router.
Thanks for reminding me - I've just added a comment to the ticket.

[#4]

Quote

Your Response 9:25am, Friday 26 Apr 2013 Another point. My attenuation is reported as 21.5 - if that is correct I should see a 8128 sync as anything up to an attenuation of 29/30 should get full speed sync on 20CN. I have never seen an 8128 sync (with interleaving on or off).

Quote

<removed> - CSC Analyst 10:09am, Friday 26 Apr 2013 Dear Mr xxx, Thank you for getting back to us. I have checked your speed and looked into your account and can see that you are on a Max Premium product. This product automatically uncaps your upload speed, any extra uploads you get will have a detrimental effect to your download. Looking at the router stats your have posted on the forum thread you have your upload speed is at 832Kbps (a capped line would generally be at 448Kbps, a difference of 384Kbps). Taking this figure and then looking at the download sync of 7808 putting them together accounts for the "missing" amount to your download. However please also bear in mind that your lines estimates are 6-8Mbps and anywhere in this bracket is acceptable. <snip>

My head is sore from when it hit the desk!

[#5]

What do people make of the bits/tone?

[#6]

This is mine on full 8128Kbps sync, for comparison -

[#7]

Are you on Max Premium or Max? What's your attenuation?
(You graph did confirm something I suspected with mine - wondering if anyone else sees the same thing)

[#8]

Here are my router stats -

[#9]

I don't know if it is relevant but this is a comparison before and after the change from 20CN to 21CN both with capped upstream
The second one is now with it uncapped after they sorted my line problem

[#10]

That is interesting. It looks like on your before there is the same gap with tones 33-36 missing as I'm seeing. I'm wondering if this is a characteristic of Marconi 20CN exchanges.
Were you by any chance having issue on 20CN with the line dropping on incoming calls?
Plusnet have now told me that there is nothing more they can do; it is a 'feature' of 20CN Marconi exchanges.

[#11]

Yes
I was having a major problem which improved significantly when moving to 21CN

[#12]

Here is my 8128Kbps sync line when on 20CN some years ago............
I had no problems with the phone interferening with the BB.

[#13]

You didn't have the big gap between the upstream and downstream.

[#14]

I've never seen tones 33-36 missing before on a line with no problems. At absolute worst you might have 2 tones missing between Upstream and Downstream, tone 32 being one of them. It depends on how good the line card is!
Other than that your Bits/tone looks fairly typical jelv. Tone 64 is the Pilot, tone 170 is the 2 bit loaded one which as I mentioned before could appear on any of the other tones instead.
It's a Faulty line card. And oh that agent's comment clealy he thinks he understands and is getting his knickers in a twist about Annex M except it use tones 6-56 for the upstream, not just a bit as he's suggesting, and downstream is tones 60-511 and it's all irrelevant anyway as it's only on business lines at Plusnet and Annex M is only 21CN in any event!

[#15]

The change I noticed wasn't the gap it was the bit loading on the downstream being hit on the lower tones