Optimizing home wiring

I've just moved into a 1.5 yr old property. There's no fibre or virgin media, 4G is a little dubious, so FTTC is the best option, and I've just signed up with Zen.

I'm getting around 51/8.5 which is pretty much at the bottom end of estimations (but just above the failure level) and in a day or so the line is stable. It's reported as fairly long by the modem at 570-580m. The BT wholesale checker gave a range around 50-80 down and 12-19 up.

Only a few months ago I had 1 Gbps cable (55 up) . Prior to that 150-250 Mbps 4G (30-50 up) .... so this is a fair bit slower

Currently I have the modem (Fritzbox) connected to one of the phone jacks via an ADSL filter (there should be no filtering, more a case of having the right connector). I have no landline phones, though there is an alarm system. I don't know if it's connected to the phone line

I've posted a photo of the socket I'm using at https://ibb.co/LxcXYYD - on the left of course is the CAT 5/6 wiring (we have points in each room), and on the right the phone jack. This is where the previous owner told me the the 'master' socket was, but doesn't look like it to me?

I found only one other phone jack in the property which is very similar EXCEPT it was 2 phone cables wired entirely in parallel. It too looks identical with the same capacitor.I am assuming that might be the first point of entry which then loops up to this one. The wiring and capacitor seems the same (I forgot to take a photo and it's behind some furniture).

This doesn't look entirely legit - I'm surprised to see a capacitor on both, and no resistor/surge protector? Unless there's another socket I can't find of course. (I could email the developer to ask)

Do you think it would have any noticeable impact on VDSL2?

Any recommendations on any mods to reduce interference?

These are the fritzbox stats:

Max. DSLAM throughput kbit/s 80000 20000
Min. DSLAM throughput kbit/s 128 -
Attainable throughput kbit/s 57409 9289
Current throughput kbit/s 55615 9289
Min. effective data rate kbit/s 55583
Seamless rate adaptation off off

Latency fast fast
Impulse Noise Protection (INP) 45 0
G.INP on off

Signal-to-noise ratio dB 7 6
Bitswap on on
Line attenuation dB 26 31
approximate line length m 575

Profile 17a
G.Vector off off

Carrier record A43 A43

This is the BT checker info: (based on address)

Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Handback
Threshold(Mbps) WBC FTTC Availability Date WBC SOGEA Availability Date
High Low High Low
VDSL Range A (Clean) 75.7 55 19.9 13.1 49 Available Available
VDSL Range B (Impacted) 74.1 51.1 19.5 12 44 Available Available
Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Range (Mbps) Availability Date FTTP Install Process
FTTP on Demand 330 30 -- Available --
ADSL Products Downstream Line Rate (Mbps) Upstream Line Rate (Mbps) Downstream Range(Mbps) Availability Date
WBC ADSL 2+ Up to 3 -- 1.5 to 5.5 Available
WBC Fixed Rate 1 -- -- Available
Other Offerings Availability Date
VDSL Multicast Available
ADSL Multicast Available
Exchange Product Restrictions Status
FTTP Priority Exchange N
WLR Withdrawal N
SOADSL Restriction Y

If a phone works at the other socket (filtered so not to mess up the VDSL2) then probably a bridge tap involved - likely the socket photo you posted is at the end, and other end is one of the double wires. So some investigation to figure out which wires are which and making so just one phone socket with the filter and modem connected.

In reply to a post by planetf1:

I've posted a photo of the socket I'm using at https://ibb.co/LxcXYYD - on the left of course is the CAT 5/6 wiring (we have points in each room), and on the right the phone jack. This is where the previous owner told me the the 'master' socket was, but doesn't look like it to me?

Looks like you have a rj45 module and a telephone master module fitted to that wall socket. The telephone master module and its associated feed is possibly not ideal for VDSL2 connectivity...

Edited by 4M2 (Sun 20-Dec-20 00:15:25)

Thanks. It does look like a simple daisy chain - perhaps the one variable is that I've not opened up the alarm panel, perhaps there is wiring in there & one might want to check for appropriate filtering.

It is probably sensible to try at some point off the original cable only, but that being said if daisy chained the socket I am using (and was told to use for broadband by the previous owner) would be the right one (end of chain) to minimize reflections

I posted my spectrum graph from the fritzbox at https://ibb.co/zHxRpfb
- 8-11 kHz does seem to suffer more (almost as if filtered?) - any thoughts on this?
- otherwise the graph look fairly linear other than where there are splits between up/down or at very low freq
- I don't notice any repeating notches that would indicate a tap problem?

So far - and I'm only 2 days in, I've noticed any resyncs or any uncorrectable errors , and the overrall SNR reported is very steady - so all looks fairly clean other than the gap

I also realised that since I now have a line I can get the BT checker info for my specific line - so for ref:

Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Handback
Threshold(Mbps) WBC FTTC Availability Date WBC SOGEA Availability Date Left in Jumper
High Low High Low
VDSL Range A (Clean) 75.7 55 19.9 13.1 49 Available Available --
VDSL Range B (Impacted) 74.1 51.1 19.5 12 44 Available Available --
Featured Products Downstream Line Rate(Mbps) Upstream Line Rate (Mbps) Downstream Range (Mbps) Availability Date FTTP Install Process
FTTP on Demand 330 30 -- Available --
ADSL Products Downstream Line Rate (Mbps) Upstream Line Rate (Mbps) Downstream Range(Mbps) ADSL Availability Date WBC SOADSL Availability Date Left in Jumper
WBC ADSL 2+ Up to 1 -- 1 to 3 Available Available Yes
ADSL Max -- -- -- -- Available --
WBC Fixed Rate 1 -- -- Available Available Yes
Other Offerings Availability Date
VDSL Multicast Available
ADSL Multicast Available
Premise Environment Status
Bridge Tap U
VRI --
NTE FacePlate --
Last Test Date 12-12-2020
Exchange Product Restrictions Status
FTTP Priority Exchange N
WLR Withdrawal N
SOADSL Restriction Y

this still indicates 12-13 Mbps up, 51-75 down.

I'm asuming SNR reductions if stable, and G.INP going off may improve the download, but not sure this will affect upload?

If BT have test data for this line, to what point is the test done?

Edited by planetf1 (Sun 20-Dec-20 11:14:41)

If the alarm is connected to the phone line, it may be an issue unless it has its own microfilter (more modern ones will have that built in).

This also makes it more complex to get down to the simplest ideal of shortest cable run and just 1 phone socket in property.

Only way to really know if the wiring is impacting is to experiment.

In reply to a post by planetf1:

I found only one other phone jack in the property which is very similar EXCEPT it was 2 phone cables wired entirely in parallel. It too looks identical with the same capacitor.I am assuming that might be the first point of entry which then loops up to this one. The wiring and capacitor seems the same (I forgot to take a photo and it's behind some furniture).

This doesn't look entirely legit - I'm surprised to see a capacitor on both, and no resistor/surge protector?

Is that assumed first point of entry, twin wall socket (?) also fitted with rj45 and telephone master modules? One pair of wires from that telephone master module may be linked to the alarm and the other pair from the same module seems to be linked to the other telephone master module that you are currently using, in conjunction with a micro filter, for the modem/router...If that is the case then the link to the alarm could be an issue even if it is filtered together with the use of two telephone master modules.

The phone socket is a PABX Master socket, hence no resistor/surge protector (ie it is not connected to an external line).

Two questions, 1) where do all the CAT5 cables go to? There should be either a CAT5 patch panel, or a bunch of CAT5s with RJ45 connectors on. 2) How does the telephone line enter your property? Via an underground duct, or from a pole via a dropwire? (Dropwire is black and very stiff) Where does either the ducted cable or dropwire connect to the internal telephone cable shown.

The alarm system, if designed to be connected to a phone system has to be connected via a filter. Do you pay for a maintenance agreement for the alarm system? (If connected to a phone system so as to dial out if the alarm is activated, then really should have a maintenance contract. If not connected, but is a requirement of your house insurance, then again should have a maintenance contract.

Cheers!

Lots of new build properties have their internal cabling run in Cat 5 Clive, it doesn’t mean there’s an RJ45 or a patch panel on them.