BT to RJ11 cable upgrade advice

My telephone is a Panasonic DECT with answerphone, and the cable between base unit and wall socket is flat. I have recently moved to VDSL2 with a modest sync for distance to PCP, and a test suggests local interference.

Is it possible to upgrade the existing cable, even say to cat5e, and might have some beneficial effect? Please!

Changing the cable to the DECT base station will have no impact.

What are your modems statistics? i.e. connection speed, attenuation and noise margin and expected distance to cabinet

If sync is low, first thing to do is check again at the test socket which should disable all extension wiring

Ideally your router/modem should be attached to the master socket which should have a filtered faceplate.
If the master socket is a more modern one with an internal test socket then, if you don't already have one, you can buy a filtered faceplate from the likes of Solwise or ebay.

You don�t describe a filter on the phone connection .. is there one ?

Oh dear, I omitted some important info from the OP.

I had a SSFP upstairs fitted to what was a hard wired extension adjacent to my computer, and the old master was relegated to an extension. The base unit is now working from the phone socket of the SSFP. The slave is downstairs, only requiring a power supply. For domestic convenience it'd be better the base and slave were exchanged. I hope that clears the matter of extensions.
Stats

S

Downstream Upstream
Line attenuation (dB): 26.5 0.0
Connection speed (kbps): 25609 4771
SNR margin (dB): 3.3 6.1
Power (dBm): 12.0 6.3
Interleave depth: 4 1
INP: 49.00 0
G.INP: Enabled Not enabled

Distance from PCP ISP says 1045m, BTOR test 1060m.

Low downstream SNR, maybe the router doesn�t run so well when it�s low.

Or maybe it�s indicative of the issue .. so if retested at the true master it might be back up at 6db again ?

I'm on a Huawei cab and G-INP is enabled, hence 3 dB attenuation. Tests were at SSFP which is the true master. Working @ 6dB would be even slower.

Router is Billion 8800NL v.1. and runs better than ISP offering.

But a 3db profile is going to produce, unless you are on a stupidly short line, an increased error count .. maybe even looking like interference.

In reply to a post by diputs36:

Distance from PCP ISP says 1045m, BTOR test 1060m.

So where did the 120m come from?

In reply to a post by diputs36:

Copper Line:
DP Line Length Estimate: 2725 Metres
DN Line Length Estimate: 2818 Metres

2818-2725 = 93 cannot be to anywhere near me, as later test on fibre indicates PCP to premises is ~1000m.
From what I am informed is my DP is according to Google Maps about 120m.

Have you moved house since 7 May?

Also "For domestic convenience it'd be better the base and slave were exchanged". Do you mean it would be better now to swap them back, which is what that says, or do you mean "it was better", which is why you had it done?

NOTE 3dB margins are not confined to working well on short lines, it can improve speeds on longer lines.

So we are back to trying to understand what this report of noise is from? It seems possible it is a mis-interpretation of the low noise margin.

So what are the actual problems with the connection, rather than the potential diagnosis of the fault.

NOTE: A 6dB margin would be a lower sync but if high errors are happening on a 3dB margin then the DLM would usually back the margin off, i.e. DLM usually only lets the 3dB margin stay if things look very good.