VDSL2 and APC surge protection

ldap · 13-10-2021 10:45pm #1

Hey all,

I’ve recently bought a surge protector for my VDSL line. I was getting a maximum rate of up to 98 meg on my line prior to installing it (it’s usually in the mid 90s) but once I plugged it in, that speed dropped to 71 meg. Is this huge drop to be expected? I’ve contacted Schneider tech support and they said that the surge protector shouldn’t affect VDSL speeds.

This is on a new line that was installed recently and since it’s coming in overhead from a pole, I need to protect my equipment from surges during a lightning storm. Our previous line was notorious for surge strikes and we lost several modems, routers and network cards over the years. The surge protector model is a APC PM5T-UK (one of those plug and phone line extension lead protector) and I chose it because of cost, ease of install and indicator lights that indicate that it’s working correctly.

Any advice would be greatly appreciated.

13-10-2021 10:58pm

you'll always have some attenuation on the line putting electronic components in the path of the connection...

While lab tests probably show a minimal, universal loss across the broadband signal, real life there is always more variables.

Do you have other equipment plugged in? Or is it solely for the VDSL?

Ex telecoms tech here, and whenever I saw a broadband issue and saw one of these in line, it was 99% the issue

ldap · 13-10-2021 11:07pm

Yeah I was expecting some attenuation but a 20 meg drop seems like a lot. I suppose in VDSL terms, 2db attenuation is the difference between 90 and 70 meg.

I’ve the modem plugged into the power strip but good point. It could be noise coming from the PSU potentially. I’ll put the PSU on another power strip and see how I get on.

14-10-2021 12:03pm

https://www.boards.ie/discussion/comment/118017032#Comment_118017032

This is the issue, there isn't more details, and quite frankly, I don't trust electrical equipment suppliers dealing with telecoms interfaces, unless it's brands like Eltek etc... who specialise in telecoms power....

Their lab tests could have been for a VDSL1 line, which gives them the right to brand it as "VDSL compatible", where the associated suppression circuitry could be horrific at the higher frequency bins of VDSL2.

You're doing what I was just about to suggest, get any PSU's as far away as possible and test with just the telephone line.

If that modem PSU turns out to be effecting it, I would replace it also, as it will be feeding dirty power into the modem which can feedback into the telephone network.

ldap · 14-10-2021 12:51pm

https://www.boards.ie/discussion/comment/118018696#Comment_118018696

Thanks for your suggestions so far. It's great to get advice from an actual telecoms engineer on this.

I've tried to get as much information from the device as I could, unfortunately Schneider aren't great at that. Also from reading their documentation, there is a conflicting info RE payout by damage done by surges (data lines are not covered by the guarantee but telephone lines are, seems like a cop out to me)

I've asked my ISP's sales rep, an Open Eir engineer and a KN engineer about putting surge protection on the phone line and they all said that I could use one. However, none of them suggested what type of surge protector I should go for. The sales rep said that he had a similar setup as me and that it worked fine for him so I just ran with that and in hindsight, that was a silly idea.

I have been looking at the Hager SPK 103 but that would involve installing some sort of earthing mechanism and any electrician I've asked didn't seem to keen on installing one for me. It is way more expensive and hard to find in Ireland. Plus, I'm not sure if it would work, despite saying that it is for VDSL2 lines. https://www.hager.ie/products-e-catalogue/energy-distribution/protection-devices/surge-protection/surge-protection-for-adsl-and-vdsl2-lines/spk103/101764.htm

Unfortunately, it isn't the PSU for the modem that's causing the issue either. I might just have to put up with it until FTTH is a thing here and the IFN programme is complete.

ED E · 14-10-2021 2:09pm

Just saying VDSL2 isnt really specific unless it says all annexes and vectored. Could be fine with 8n but useless with 17/30.

Did you use a new cable with the surge protector? (as it will require two where there was one) - If so please check that the 2nd patch isnt crap flat cable
The ideal setup would be to use a media converter between the VDSL modem and the rest of your network using the modem as a sacrificial lamb.

ldap · 14-10-2021 4:14pm

Good point. VDSL2 can mean anything. Maybe my surge protector is not tested on 17a or vectoring hence the huge drop in potential bandwidth. Same with the Hager device I linked earlier hence why I didn’t fork out the €80 odd quid on it.

I’m using the supplied patch cable. That was my initial thought, I made a really short patch cable from a CAT5e cable I had laying around and it came back with the same results so I ruled it out, but I did pull one of the 4 pairs out as I didn’t have enough space to crimp properly. I could make another patch cable out of a better quality cat6 I have. Doubt that it will help though at this stage as I suspect it is the filtering of the SPD that’s causing too much attenuation.

Media converters would be ideal but oddly, I actually like our new ISP modem. It’s not amazing but it’s much better than anticipated. I had a lovely Archer AX10 until it blew up last month and I got a good deal on WiFi6 mesh systems that work natively with the ISP modem and supports Ethernet backhaul (compared to the TP Link onemesh which doesn’t support Ethernet backhaul. Unfortunately I didn’t realise this until several month after buying the AX10) Using the ISP modem means I can power it from a 12v UPS for whenever I get around to assembling that project. Also I want to keep the network as simple as possible as I’m not always around to fix it when it goes wrong.

15-10-2021 6:24am

https://www.boards.ie/discussion/comment/118019496#Comment_118019496

Just on the last point, the product has RJ11 sockets, so would be in line before the modem.

I wouldn't suggest the modem as a sacrificial lamb either.... you can get some seriously dangerous results from lightening getting into a premises and hitting equipment.... lightening suppression first at point of entry

ldap · 15-10-2021 2:29pm

https://www.boards.ie/discussion/comment/118022078#Comment_118022078

There is a lightning rod on the house next door to us as there's basically a mini forrest growing around it. When it was installed, we were told that it would protect our house and other homes close to it. Not sure if that's still the case or not, but no surge protector in the world will save us from a direct hit.

I've emailed Schneider to ask them more specifically about what profiles it works with etc. If I get an unsatisfactory response, I think I'll just use the current SPD the cordless phone and then get a proper SPD rated to work with profile 17a if I can find one. (I think OpenEir gave up on rolling out 30a and are just concentrating on FTTH instead)

I can't go anywhere near Open Eir's equipment so I'll have to put any surge protection devices after the NTU unfortunately. Not ideal, but better than nothing I suppose.

15-10-2021 2:34pm

Bear in mind there are multiple versions of VDSL2 and OpenEir and BT in the U.K. don’t use the same versions. There’s a difference in the ranges of frequencies used. So some devices simply don’t work or will not work at full speed.

Vectoring isn’t the issue. That’s more about compatibility between the modem and the DSLAM.

It’s possible the device you’ve plugged in is slicing off some of the frequencies or messing up the signal in some unknown way that it wasn’t tested for as you’re using it on a network it isn’t intended for.

In general, the risk of a surge on a phone line is minimal and the main phone socket will take the brunt of a lightening strike. Countries with significant lightening problems (Ireland isn’t one) usually mandate surge arrestors on any aerial lines (phone or power).

The VDSL modem / router is also fairly low cost and mostly owned by the ISP so would be replaced. That’s likely the calculation made on cost vs benefit here.

Some continental telcos VDSL specs are the same as openEir. I can’t remember off hand what the exact details are.

They're winding down the copper network, so I would assume they’re not going to bother with rolling out further vectoring updates as they’ll want to move customers to GPON and abandon legacy stuff as it’s expensive to run.

They’re in the process of moving the Alcatel E10 and Ericsson AXE local digital exchanges over to a Nokia MSAN VoIP platform at the moment to support legacy voice services on copper. Some of them are already cut over and they all will be by sometime in 2024, but they envisage a much smaller number of copper line users.

I don’t think VDSL will even be offered for sale in areas with full fibre in the coming years. Whole network will be FTTH, with support for voice on copper using VoIP for legacy users who don’t use data. Makes no economic sense to maintain two parallel networks, one of which is old and complicated.

ED E · 15-10-2021 3:25pm

https://www.boards.ie/discussion/comment/118022078#Comment_118022078

Well it's happening no matter what.

If you put in an arrestor after the NTU you still get 100kV or whatever down the drop wire. Big black line down the wall is common. So saving your home network is all you can do as an end consumer. Yes you can put a rod above your house but if the lighting lands 5 spans away and travels down the line to you its feck all use to you.

CPE is cheap (€5 for the ISP, €50 when sold to the consumer). Your new PS5/iMac/Dell are not. Media conversion optically insulates them.

I was getting a maximum rate of up to 98 meg on my line prior to installing it (it’s usually in the mid 90s) but once I plugged it in, that speed dropped to 71 meg.

You dont specify the actual values but mention a 2dB loss. At 98Mb lets assume you're on a short loop of say 400m. 2db is essentially like adding another 200m to to the loop.

Think that chart is a little stale but give you an idea.

Honestly that protector is a cheapo thing. I'd either buy telco specific gear or use nothing at all.

15-10-2021 4:02pm

doesn't matter how cheap the equipment is to replace if it causes a fire in the premises...

safest way is lightening suppression before entry, usually a gas discharge tube with it's own ground (should be fitted by OpenEir)

if customer is fitting their own additional suppression, it should be before CPE...

You still even have a scenario of the NTE capacitor blowing up and taking the socket off the wall with the above setup

If you're going to do it, do it right...

Also CPE doesn't always save things after. it I was on storm damage repair a few years back and the amount of fried NIC's, PC's on a whole and even some guys server, all destroyed, and most were after the modem with some equipment in between (firewalls, additional switches)

Like you said, when it gets in the network there's not a lot you can do, but you can takes steps to mitigate it, but the main aim is stopping things blowing up and causing fires

ldap · 15-10-2021 11:26pm

Right. Schneider is being useless and keep saying that their device doesn’t impact speeds, which is clearly nonsense.

I’ve sent DHEN an email asking them about their DEHNbox TC B 180 product (newbie here. Can’t post links despite posting a link to the Hager stuff earlier) and does is specifically work with 17a (I forgot to mention vectoring. Ugh). If they come back with yes, I think I’ll go for it and try and get my money back from Schneider/APC.

Thanks everyone for their advice. I think the lesson here is that cheap surge protectors affect speeds and ones not installed properly affect safety.

Here’s hoping the IFN programme comes to my area soon.

VDSL2 and APC surge protection

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