Kitz Forum
Broadband Related => Telephony Wiring + Equipment => Topic started by: Weaver on March 25, 2017, 01:54:15 AM
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I’m wondering about using RJ-11 to RJ-45 DSL cables for the modem to wallsocket link. We have talked about this before quite a few times.
I use Tandy RJ-11 to RJ-11 ones currently, but I'm wondering if RJ-45 plugs might be a better fit with the non-filtering faceplates / NTE5/A-fronts that I have. The filterless fronts came from the Andrews and Arnold Shop (https://aa.net.uk/broadband-accessories.html) It explicitly says they are RJ-45 sockets, not RJ-11, but does it even matter? Or is ‘good enough’ good enough?
The cables that I am using are Tandy (former ADSLNation) 0.5m and 1.0m ones (http://www.tandyonline.co.uk/high-speed-rj11-dsl-cable-0-5m.html) which have a real quality feel to them. They measured extremely well compared to the cables I was using before, a shocking difference, one which could be down to bad testing methodology, or shoddy construction of the other cables, or both. This has been discussed in earlier threads.
The alternative I was thinking about is https://www.run-it-direct.co.uk/rj11-to-rjJ45-patch-leads/RJ11toRJ45patchlead1M/ which is very expensive by comparison and the appearance fails to seduce: not gold-plated, unless they're keeping it a secret, twisted pair but no overall shield, no moulded plugs so less robust-looking and no metal around the plug bodies. I don't see any immediate reason why they might be an improvement, and at a far higher price
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All of the OpenReach MK(1,2,3,4) filtered faceplates also have an RJ45 socket. Most people don't even realise it's RJ45 as the ISP supplied RJ11 cable fits as expected.
I use the same unfiltered faceplate as yourself, purchased directly from AAISP. With both the OpenReach filtered and the AAISP unfiltered faceplates I prefer using a cable with an RJ45 socket. It fits much more snug, as the smaller RJ11 has a bit of "wiggle" in the RJ45 socket.
I use a RJ45 to RJ11 cable made by Mr Telephone (My mate Vince), purchased from his EBay store. I recall you saying in the past you had a bad experience with 1 of his cables. I've tried expensive Belkin cables and the Tandy cables and neither performed as well as Vinces. His cable being RJ45 at 1 end is a nice bonus.
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Run IT Direct have changed their DSL patch cables since I bought one.
They have a CAT-5e one which is higher specification and cheaper than the one you linked to:
https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/adslvdslcat5patchlead1m/ (other lengths also available)
The one I bought used a standard 4-pair CAT-5e Ethernet cable, and only wired one pair to the centre two pins of the plugs. Now they are using 2-pair cable and wiring up both pairs to the RJ-11, not that wiring up a pair of wires which aren't going to be used for anything will make any difference.
The more expensive cable you linked to is not CAT-5, it's telephone grade CW1308.
I suppose nobody makes high specification cables with an RJ-11 plug on one end and a BT phone plug on the other, then you wouldn't need a special faceplate.
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Ejs wrote:
> suppose nobody makes high specification cables with an RJ-11 plug on one end and a BT phone plug on the other, then you wouldn't need a special faceplate.
Good point. I had thought about that, it would just mean a posh dial-up modem cable, and they must still be around, from someone such as Belkin. However they will all be too long by far, and you can't beat shortness.
@j0hn - thanks for the tip about your good experience with Vince. The one that I had was simply falling apart, perhaps I would have done fine with a different individual unit. I should perhaps give Vince's ones another try. I have to say though that measuring these things is tricky because of DLM messing you about and if I were doing the comparison now I would be much more careful about it. (See http://forum.kitz.co.uk/index.php?topic=15905.0 )
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I have decided for the sake of science to compare a short 0.5m Vince CAT6 RJ11-to-RJ45 cable with a Tandy one. I will do so carefully this time and report back. I think that he even does 0.3m ones, if memory serves.
What is the best thing to capture? Simply go on sync rates with repeated a-b comparison? Do we try and get some information about SNRM over time? Or some kind of error rates?
One way of looking at it is to think of science only and try to decide on which measure is the most revealing in some aspect or other than you have to argue about the relevance of that measure.
The other way is just to decide what you want to see optimised and your preference is what it is. In my case I am just trying to optimise sync rates, first downstream and then upstream. And I am trusting the systems to keep to a standard level of reliability so that we are comparing like with like in the sense that we don't by some strange miracle end up with modem plus cable A going faster than B but at the expense of differences in SNR.
My modem of one of these cables is that it has a certain transfer function and lets in a certain amount of noise. Is that fair enough? Do I need to mentally include impedance mismatch/ power transfer?
Someone who has ready access to full stats from their modem might be in a better position to make the comparison. Even if I were to isolate a modem and telnet into it I can't use the good continuous stats capture tools that most of us have because of the firmware in question. Any volunteers to try the two cables back to back?
I have the advantage of a very weak DSL signal so I tell myself that these small effects are more significant in my case than for someone with a short line and hence high voltage. However, I am not testing higher frequencies so that could mean that the reverse argument could be made, that a VDSL2 user might be able to contribute something that I cannot. Perhaps we need a slow long line user and a VDSL2 user both?
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All I'm going to say on the subject is that all the theoretical improvements made to my setup, getting a modern master socket, CAT-5e modem cable, even getting rid of the star wiring and numerous superfluous crimps and little bits of wire, made no significant difference to the line rate.
I wouldn't be at all surprised if any differences between the cables are so small that it's difficult to measure accurately given all the uncontrollable external factors.
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I have a star-wired extension setup and when I used to have ADSL the single biggest improvement was to disconnect the ring wire going to the extensions. This pushed my ADSL speed from 5Mbps up to about 6.5Mbps.
Fitting a filtered faceplate then gave me about another 0.5Mbps on top.
:)
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Trouble with any such testing is, no two syncs, even with the same cable and minutes apart, are guaranteed to be exactly the same. It might depend upon whether the central heater stat has kicked in, or whether radio 4 is broadcasting laughter or silence, or what direction the radar station at the local airbase happens to be pointing, or dozens of other random factors.
I would argue any tiny differences that might appear to be attributable to cables are pretty much indistinguishable from these random factors. You can reduce the random effects by doing enough tests that the random stuff statistically cancel out, but DLM would spotted all the disconnects, and would have intervened long before you got to that point - ruining the experiment.
On the odd occasion I have tried to do any such testing, I have found no solid evidence that posh cables make the slightest difference.
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I was talking about star wiring connected to the line before the master socket. If a filtered faceplate would have solved the issue, it would have been far simpler to fix.
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Anyway, back to the subject of cable testing. Even if you swap the cables very quickly and find you get a higher speed with one cable, you might find that later, under different environmental conditions, at a different time of day or night, the other cable is better.
Rather than compare two high-specification cables, perhaps also compare the ordinary lead that came with the modem.
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The cable I bought from Mr Telephone increased my sync by 2-4mb (taking account of usual variations). My line attenuation also dropped by 0.1
VDSL2 certainly appears more sensitive and is more likely to give gains with a better modem cable.
After ADSL running along nearly 8km of copper, the last 0.5m is never going to make a huge difference. If I were you though Weaver I couldn't help but try anyway ;D
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I beg to differ about the last small length. This is my thinking: The last x km are clean electrically and then suddenly we enter a house full of electronic noise. The other thing is that attenuation means that we are dealing with very small signal voltages so (noise / signal ) ratio is most significant at my end of the downstream. I may of course be well wrong as I have no idea about the magnitude of these numbers even if the logic is sound.
The other thing is that like you, I got a really substantial difference by switching cables before something roughly >20%. But possible bad testing methodology back then is something that bugs me.
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I completely agree with the earlier posters about the noise in the test results anyway, and indeed the effects might be too small (by a huge long way) for the resolution of the procedures we have at our disposal.
But my thinking is that if anyone has a chance of seeing such effects (and perhaps no one has a chance) then it's me, because of my low signal levels and uncannily clean house-external noise environment (apart from things like radio stations), because most people have human civilisation all around their conductors’ run outside their premises. Having said that, it is perhaps an unhelpful thing that I am not testing umpteen higher frequencies at all when compared with normal people.
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Just a few comments --
- I fail to understand how a screened cable with metallised plugs on its ends can be superior to other cables if the screening is not connected to a good signal earth.
- As much as I like Vince (Mr Telephone Supplies (http://stores.ebay.co.uk/mrtelephonesupplies/)), I disagree with his policy of attempting to make patch cables out of the solid core cable used for structured wiring. Structured wiring -- solid core. Patch cables -- stranded core. As other have discovered, the plugs crimped onto the solid core wires of Vince's patch cables will come off, sooner or later.
- As ejs has mentioned, Run IT Direct (https://www.run-it-direct.co.uk/) now have a different set of patch cables (https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/) available. (8P4C modular plug and 6P4C modular plug, respectively, at opposite ends.) I would be tempted to use one of those cables.
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- I fail to understand how a screened cable with metallised plugs on its ends can be superior to other cables if the screening is not connected to a good signal earth.
I know opinions differ within the forum, but I strongly agree with Burakkucat on this aspect.
In fact, I would argue such a cable ought be inferior to a normal unscreened cable, for the reason that any increase in conductor surface area will lead to an increase in currents induced from interference. If the energy produced by these currents cannot be transferred to a good earth conductor, then that energy will have to go somewhere else. In the absence of an earth, the energy will transfer to the internal conductors, adversely affecting SNR, and making matters worse.
But I did say, opinions differ. I would not be surprised if other opinions were to come along soon. :)
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I won't be contrary, I agree with the two of you. :)
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@burakkucat - I hear you. I didn't know about the solid core thing. And guess what, the Vince cable that I had fell apart. It didn't look anything like the ones in the current product shots.
I will intentionally waste a small amount of money though, in the interests of science only, but I am not optimistic - either about there being anything there to measure, or the possibility of it being measurable given the techniques available, or about the magnitude of any effects rising about the measurement noise floor. I will certainly take a look at those alternative run-it-direct links.
Many thanks to all contributors for valuable insights.
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@Burakkucat - Physics - is the point that my supposed Faraday cage is very imperfect and the shield acts as an aerial? Inside the shield is the gradient of the potential zero? Is it an issue concerning dV/dt inside the shield too?
Skipped most electromagnetism lectures - was too busy fiddling about writing Z80 assembler language at the time til all bourse, and playing games instead of working.
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Skipped most electromagnetism lectures . . .
It was a very long time ago, I have probably forgotten more than I have remembered. ::)
. . . is the point that my supposed Faraday cage is very imperfect and the shield acts as an aerial?
Hmm . . . Or acting as a parasitic omni-directional director. (Whatever that may be.)
Inside the shield is the gradient of the potential zero? Is it an issue concerning dV/dt inside the shield too?
Bond the screening to a good signal ground and then the screening will behave correctly. Perhaps 7LM could help out with answers to your latest questions? :-\
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Perhaps 7LM could help out with answers to your latest questions? :-\i
I have a scroll of paper upstairs, from a respected academic institution, that suggests I once knew about such things. But that was then and this is now. After a working life spent (miss spent?) in software development, i would be unable to speak with any confidence. That is why I generally try to express an opinion, rather than a fact.
Sometimes, believe it or not, I am sometimes even wrong. That is why I was inviting different views.
Must confess, I have just spent a few moments trying to dig up online technical material, but have found nothing I can cite to justify my suggestion that an ungrounded screen is worse than no screen. Various posts on various forums, some agreeing and some disagreeing, but nothing really authoritative. :-[
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Hmm, I always thought an ungrounded shield was worse than none at all but I have found quite a few articles that suggest it is not so.
One example is http://www.cablinginstall.com/articles/print/volume-15/issue-7/features/design/the-myths-and-realities-of-shielded-screened-cabling.html (http://www.cablinginstall.com/articles/print/volume-15/issue-7/features/design/the-myths-and-realities-of-shielded-screened-cabling.html).
:-\
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The alternative I was thinking about is https://www.run-it-direct.co.uk/rj11-to-rjJ45-patch-leads/RJ11toRJ45patchlead1M/ which is very expensive by comparison and the appearance fails to seduce: not gold-plated, unless they're keeping it a secret, twisted pair but no overall shield, no moulded plugs so less robust-looking and no metal around the plug bodies. I don't see any immediate reason why they might be an improvement, and at a far higher price
The lead you have linked to is not designed explicitly for ADSL/VDSL, they are wired for connecting Panasonic KXT-DA0141 & KXT-DA0142CE DECT Cell stations to structured cabling (4 wires connected). The pins are gold plated like just about every RJ series plug available, we don't make a big deal over that as to be frank it would be marketing drivel but we'll certainly get it added if that is what people are expecting to read! As for shielding, totally & utterly pointless. For a shielded system to work the cable MUST be grounded at both ends. As the incoming line has no ground & there is no grounded shield on ANY filtered faceplate socket this would be impossible to achieve. Indeed almost all modems/routers have no shielding on the DSL input socket either (& if they do that is more to do with internal RFI shielding than grounding the socket). For ADSL/VDSL leads this is what we offer :- https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/
The VDSL ones use BT CW1724 spec cable which is a two pair cable to CAT5e specifications. We only terminate one pair as that is all that is required. Our customers report improvements when using these cables but obviously like anything involving DSL this can & will vary which is why we do not make any bold claims. Hope this clears things up a little.
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Hmm, I always thought an ungrounded shield was worse than none at all but I have found quite a few articles that suggest it is not so.
One example is http://www.cablinginstall.com/articles/print/volume-15/issue-7/features/design/the-myths-and-realities-of-shielded-screened-cabling.html (http://www.cablinginstall.com/articles/print/volume-15/issue-7/features/design/the-myths-and-realities-of-shielded-screened-cabling.html).
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I've only skeeted through that but in our tests shielding did not improve things. Trying to attribute every tiny improvement or impairment down to one thing is quite difficult due to DLM etc. My personal experiences of shielded cable in the network environment (CAT5e/CAT6) was grounding was certainly required in electrically noisy environments like factories (which tended to be the only places where shielded systems were specified).
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For a shielded system to work the cable MUST be grounded at both ends.
Grounding on both ends can cause ground loops - especially for structured cabling connecting between rooms which will be on different circuits. It's usually okay for patch cables as the cables are going to be terminated on both ends in devices which are on the same circuit.
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I've ordered some of these
https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/adslvdslcat5patchlead025m/
in a mixture of different lengths. It's good that run-it-direct do really short cables. Thanks to ejs for that tip.
I will try my very best to do the right thing statistically when comparison testing. It will be Tandy vs Vince vs run-it-direct. I certainly won't be surprised by a null result. Ideas:
- This procedure (at a minimum) will be used in order to keep DLM at bay:
http://forum.kitz.co.uk/index.php/topic,15905.msg295891.html - Cables will only be switched over while modems are powered down.
- I have also thought about always rebooting a modem several times after switching cables and having two presentations, one with the first result immediately after the cable switch-over excluded and one with it included. A minimum of three measurements after each swap would give a measurement of the noise in the results and excluding the first one would be interesting.
Does anyone have any suggestions to improve my chances of getting anything meaningful out of it? (Slim though they may be.)
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Just a few comments --
- I fail to understand how a screened cable with metallised plugs on its ends can be superior to other cables if the screening is not connected to a good signal earth.
- As much as I like Vince (Mr Telephone Supplies (http://stores.ebay.co.uk/mrtelephonesupplies/)), I disagree with his policy of attempting to make patch cables out of the solid core cable used for structured wiring. Structured wiring -- solid core. Patch cables -- stranded core. As other have discovered, the plugs crimped onto the solid core wires of Vince's patch cables will come off, sooner or later.
- As ejs has mentioned, Run IT Direct (https://www.run-it-direct.co.uk/) now have a different set of patch cables (https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/) available. (8P4C modular plug and 6P4C modular plug, respectively, at opposite ends.) I would be tempted to use one of those cables.
burakkucat could you be kind enough to link to what you consider the highest quality short cable on run it direct?
I noticed they have a paragraph stating cat5e is best quality for a patch cable yet the cat5e cables are the cheapest which makes it confusing.
is this one provided by ejs the best quality https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/adslvdslcat5patchlead1m/ ?
Thanks
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Grounding on both ends can cause ground loops - especially for structured cabling connecting between rooms which will be on different circuits. It's usually okay for patch cables as the cables are going to be terminated on both ends in devices which are on the same circuit.
Different circuits shouldn't make any difference they should all be connected to the same earth connection at the DB (as would the patch cabinet at one end & the equipment at the other).
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burakkucat could you be kind enough to link to what you consider the highest quality short cable on run it direct?
I noticed they have a paragraph stating cat5e is best quality for a patch cable yet the cat5e cables are the cheapest which makes it confusing.
is this one provided by ejs the best quality https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/adslvdslcat5patchlead1m/ ?
Thanks
Which leads are you comparing?
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@chrysalis - I think ejs and Burakkucat Both linked to the exact same one that I ordered. I've ordered several 0.25m, 0.5m and 1m, and I'll see what I can get away with in terms of keeping them all as short as poss. If I can get away with the 0.25m ones then so much the better. I am using two 0.5m cables currently but found it a bit uncomfortable reaching the third wallsocket, so currently I have one 1m.
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Different circuits shouldn't make any difference they should all be connected to the same earth connection at the DB (as would the patch cabinet at one end & the equipment at the other).
I'd been taught that this causes the shielding to become a parallel path for ground current to flow, inducing common mode noise on the cable inside the shield.
That is correct but not actually significant and it should be bonded at both ends. Sorry for the misinformation.
Some references supporting your statement that they should be bonded at both ends:
http://www.compliance-club.com/archive/old_archive/020514.htm
http://www.siemon.co.uk/us/standards/Screened_and_Shielded_Q_and_A.asp
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Did that article referred to earlier
http://www.cablinginstall.com/articles/print/volume-15/issue-7/features/design/the-myths-and-realities-of-shielded-screened-cabling.html
say that even an unearthed screen is a good thing, by 20dB ?
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burakkucat could you be kind enough to link to what you consider the highest quality short cable on run it direct?
Very remiss of me. (Naughty cat!) The Run It Direct (https://www.run-it-direct.co.uk/) leads I would use all have stock codes beginning with the four letters "AVPL", as listed on this page (https://www.run-it-direct.co.uk/adsl-vdsl-patch-leads/).
As for shielded cables, the shielding should be connected to a good quality signal ground and not a power supply earth/ground.
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ok thanks :)
think I am going to hold off for now, not exactly a purchase I urgently need, and delivery costs more than the product.
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for reference I did order, but maybe as feedback to the rep here to add a cheaper delivery option for small items. Also with it been recorded only one has make sure they in to sign for it.
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The decision to send ALL orders via recorded delivery was made because of the number of items going "missing". The margins are so small that one missing item means you have sell X number again to make up for it. The fact was it wasn't down to Royal Mail either as a few were investigated & found the items were delivered, which the customer later admitted when faced with legal action from RM! We could offer a 2nd class recorded delivery option but the saving would only be about 90p on small items. We can't compete with the likes of Amazon who will deliver an item next day for free.
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Can't blame you, must be a nightmare when customers start taking advantage. And plus points for not trying abusive charges for anything on the north side of the Forth bridge. Or is it Humber bridge, can never tell.
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More likely the Humber Bridge as even that is a long way North of Watford Gap. ;D
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amazon dont deliver next day for free :) you pay a pretty hefty fee for amazon prime and that still excludes cables which can only be ordered as addon-items for larger orders so presumably they have the same commercial problems.
However if you compare to something like ebay where you get sellers with "fast and free", to get that status I think it needs to arrive within 3 days, so presumably second class non recorded gets the cost low enough.
For a cable I would accept non first class personally so second class recorded the 90p saving can be considered significant on an item thats worth circa £3.
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I noticed a decent improvement when changing from the HG612's bundled ADSL cable to an ADSLNation/Tandy cable.
The bundled cable was really very long, so initially I just cut it to size and connected it to the data extension terminals inside the faceplate. This cut attenuation from 22 to 21.5. Then, after an OR engineer (rightly) told me off for using stranded cable in an IDC punch-down terminal, I switched to the ADSLNation cable. That took me down to the present 20.5 (although as the weather warms, it's crept up to 20.6).
Unfortunately, the ADSLNation cable's still a bit too long. I'm almost tempted to cut that to length too and use the data extension terminals again. But, law of diminishing returns and all that.
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so presumably second class non recorded gets the cost low enough.
But gives us zero protection against all the "it didn't arrive" thieves. Sadly experience has shown if they can try it on they will & without proof of delivery Pay Pal will ALWAYS side with the buyer. We will never be the cheapest to purchase from & never have been, what we do promise is a fast and friendly service.
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I'm truly a bit shocked, I had no idea this form of thieving had become an issue. And like shoplifting it must be driving up costs for the rest of us. >:(
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But gives us zero protection against all the "it didn't arrive" thieves. Sadly experience has shown if they can try it on they will & without proof of delivery Pay Pal will ALWAYS side with the buyer. We will never be the cheapest to purchase from & never have been, what we do promise is a fast and friendly service.
yeah hence I said 2nd class recorded is a happy medium, saves 90p but still signed for. :)
Or just bump the price of the product and lower delivery, it makes it seem better value on the delivery. :)
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Runitdirect you may get some more orders from Leicester depending on how things go, I plan to test the cable on a few adsl connections near me and if the results are good I will point the people to your website to order their own cable, I probably wont be testing it on my line for a while tho as I am not dropping my current sync manually.
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Ditto.
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yeah hence I said 2nd class recorded is a happy medium, saves 90p but still signed for. :)
Or just bump the price of the product and lower delivery, it makes it seem better value on the delivery. :)
Thank you for your feedback.
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I am using vince's RJ11 to RJ11 1m CAT6 cable from data socket to modem with out any issues most plugs don't like being removed and inserted into a socket 10 times a day what are you doing over there Weaver :o you will wear out the copper coated pins on your modems DSL socket ;D
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I have ordered a Vince cable. Not sure if it has arrived or not yet.
I'm afraid I don't follow NewtronStar. The earlier Vince cable that I had - a couple of years ago - was looking pretty sorry when I first got it, and it didn't fall a long time later apart because of repeated fumblings. The new ones could well be very different. Does that help?
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We talked about DSL cables years ago should we use the supplied ISP none twisted type or use DSL cable that has two or four pairs in the twisted configuration most said they could not see a big difference in sync, but if have a lot of electrical/electronic equipment in your Man Cave and the modem is close by then use good twisted DSL cable from ADSL/FTTC socket to modem as it should subdue most of those internal interferers.
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Or woman cave. I can't see any reason not to use twisted pair at least. I do try very hard to keep mains away from my dsl cables which are ridiculously short. Since the modems are dc anyway, there is nothing to worry about, but there is ac mains to the router so I have to keep that cable away from the modems. I doubt it matters unless they are really close, depends on which power law is in effect.
(I'm assuming that it's basically it's an O(r -1) field but then you need to differentiate that because of the protection given by common mode rejection, so perhaps O(r -2) is what we need. Any chance that that is correct?)
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Vince makes up his patch cables using solid-core wires. Cables with solid-core wires should only be used as structured wiring. I.e. Fixed in position, by cable clips, by staples, in trunking, in conduit.
Patch cables, by the very nature of their usage, should be flexible. Flexibility by virtue of the usage of stranded wires.
An xDSL signal (be it G.992.1/G.992.3/G.992.5/G.993.2) is a radio frequency signal, constrained to the wires in the cable. The cables should not be thought of as a pair of wires carrying DC or very low frequency AC but as radio frequency feeders.
The higher the frequency, the bigger the skin effect, the greater the attenuation. At a particular radio frequency, which cable shows greater attenuation? That consisting of: (1) a pair of solid-core wires or (2) a pair of stranded wires. (In each case, the total quantity of copper used in each wire of those two cables is identical.)
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Vince makes up his patch cables using solid-core wires. Cables with solid-core wires should only be used as structured wiring. I.e. Fixed in position, by cable clips, by staples, in trunking, in conduit.
Isn't that what the run-it-direct vdsl patch cables linked above use? They use CW1724 solid core bought direct from BT Cables.
I'm tempted to give 1 a go as Vince's vdsl cat5e patch cable was an improvement on my line. My modem doesn't really move but the cable is flexible enough for my needs. As to Vinces cable falling apart, the white rubber moulding covering the rj45 port is supposed move as I recall that being a previous complaint.
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I agree entirely with Burakkucat. I am getting one for the sake of science.
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Different circuits shouldn't make any difference they should all be connected to the same earth connection at the DB (as would the patch cabinet at one end & the equipment at the other).
From an electrical safety point of view that's correct, they'll all be within the same equipotential zone which might or might not equate to true earth. When considering very small signals I'm not so sure. For example building an audio amplifier it was necessary to keep the grounds on a sort of star, with each path being grounded only at one end. .
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@displaced - the AdslNation / Tandy cables are available in 0.5m lengths and the run-it-direct cables are even available in 0.25m lengths. Hurrah! That should be short enough for you. I though I had it bad. You have it bad.
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I brought some ferrite thingies to try and solve noise problems going through a usb charging cable to my headphone amplifier (it only gets no noise when direct to a phone charger). I was wondering if they would work on dsl cables as well, but wont even bother trying as it didnt even do anything on the usb cable noise.
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Do you think I should stick one of these on my drop wire Chry :hmm:
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Surely you don't want to be putting ferrites on your signal cables? Who wants to attenuate high frequencies, or am I going mad?
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Ferrites come in numerous different grades with widely different characteristics. To be any use they have to be matched to the particular requirement, which needs knowledge. You can't just go out and buy whatever ferrite rings happen to be available and expect them to solve interference problems.
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Roseway, how would I select the correct ones? I want to stop noise getting up the DC cable into my modems?
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Surely you don't want to be putting ferrites on your signal cables? Who wants to attenuate high frequencies, or am I going mad?
was just a theory bud, they were purchased for noise on my usb cable's.
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Chrysalis - no offence meant at all, I was just sanity-checking myself. I'm assuming that ferrites will be really bad for data signals.
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Roseway, how would I select the correct ones? I want to stop noise getting up the DC cable into my modems?
It's far too many years since I worked for a company which made them (among many other things) so I'm not qualified to advise. But this article might help:
https://www.allaboutcircuits.com/technical-articles/choosing-and-using-ferrite-beads/
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> many years since I worked for a company which made them
Much respect.
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I have done the first set of measurements with the runitdirect cables and compared them with the Tandy cables. This is not a fair comparison because the runitdirect cables are all half the length, 0.25m * 2 and 0.5m for the third, whereas the Tandy cables are 0.5m and 1m. Also proper anti-DLM precautions have not been followed, and this is not a decent statistical sample so extreme caution has to be taken.
The runitdirect direct cables synched around the same rates as the Tandy cables, on average very very slightly slower in both directions ( < 0.3% down, < 1% up ) not at all statistically significant and they were not consistently slower either so I suggest no conclusion can be drawn. Also SNRM figures at the time of the Tandy measurement were all over the place so no conclusion can be drawn from them, but if decent repeat SNRM figures can be captured it might be worth trying to include initial SNRMs into the evaluation of the synch results (somehow?). The attenuation figures both down and up were a fixed 0.1 dB worse for the runitdirect cables consistently across all lines. Within the limitations of the fact that this is only one sample this is an interesting result that the runitdirect cables cause everso slightly more loss even though they are half the length. But set against this is the fact that the lines have a 0.6dB downstream / 0.5dB upstream spread between them anyway, despite the fact that the runs are identical, so it could just possibly be that this 0.1dB is merely within the noise threshold. However it is interesting that the difference is fixed.
So the Tandy cables have a possible extremely slight performance advantage over the runitdirect cables, but you would do very well with either.
Mrs Weaver said that the runitdirect cables were an extremely good fit, having the strictly correct RJ45 plug on the wallsocket end.
So at this extremely early stage there is nothing much in it, as expected.
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bad news from me, when i inserted the cable was no click also the cable came out too easy just a slight bit of pressure and pops out the socket, test on two spare faceplates and is same (done video of it)
i tried it anyway but no sync at all, if i put pressure to push cable in the dsl started to sync but stopped when i let gom so seems a dud and maybe these larger connectors are not as good as is said.
now do i return for an exchange the postal costs vs the value of the cable skyrocket
https://www.dropbox.com/s/nr5myva37h5j0c0/20170413_064440.mp4?dl=0
https://www.dropbox.com/s/es8t4jfei18umgd/20170413_064216.mp4?dl=0
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Not wanting to insult your intelligence, but have you tried pulling the pressure relief sleeve back before inserting into the socket.
Used to get this a lot with Ethernet fly leads and it was nearly always that the sleeve was stopping the cable going all the way into the socket.
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how do i do that im not sure what you mean
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now its ok i pulled that rubber sleeving away its loose now on the cable not sure what its purpose is, thanks
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It's has two purposes in life: one functional and the other aesthetic.
The functional element is is that it is there as a stress reliever in case someone pulls the cable at an angle. It just stops teh cables being bent sharply where the go into the RJ45 plug.
The other reason it is there is to make it look a bit nicer as it hides the cables going into the RJ45.
All we used to do is pull the sleeve back, plug into the socket and then push the sleeve back against the face of the socket.
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thats what i have done now although its loose so i dont think it will do much to prevent stress
line is now using it so can asses error rate
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Will be interested to hear your feedback on the cable performance.
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thats what i have done now although its loose so i dont think it will do much to prevent stress
line is now using it so can asses error rate
That's how they are designed. Vince's cables have similar rubber moulds that slide back when connecting the cable and a few complained his cable fell apart on them but they are designed to be like that.
For handmade cables with solid core cabling they either leave a blank rj45 connector or cover it with the rubber sleeve. You could cut it off if you see no purpose for it but I find it protects the release clip from damage especially when unplugging the cable. It's only on mass produced cables that you'll get a fixed moulded cover and I've never found 1 with solid core wiring.
Let us know how the cable performs with your VDSL2 circuit Chrysalis. The delivery cost put me off ordering but might bite if they do a good job.
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im on mdws so you can watch :) my main curiosity is if it helps the afternoon error spikes which i think are local
note there is a chance i may get interleaved today which will interrupt the test
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I got the Vince / Mr Telephone CATx RJ45-RJ11 cable and it looks rather better made than the earlier one as the cable type itself is much better suited to attachment into an rj11 plug.
It will take a long time to have _any_ chance at all of detecting any performance difference, if such even exists, because random variations affecting modems' choices during training have so much noise in them. I think it might even require multiple resyncs with anti-DLM techniques applied and then comparisons done _at the same time of day_ when the levels of alien activity are comparable. There seems to be just too much noise sometimes in sync rate figures.
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Errors are very low on the DS, I am comparing to when my line was last on the same SNRM, so before nov 2016 and the ES is lower and the CRC to ES ratio is a lot lower.
US ES is higher than before the cable swap and I now find myself with the DS error rates less than double of the US ES O_o.
Errored Seconds
DS avg 3.64/hour
US avg 2.13/hour
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I am thinking about going for all 0.25 m cables and sticking the modems onto the wall somehow. Suggestions?
I am not sure, but I don't think the modems have picture hook things, whatever they are called, on their underside.
It would have to be with double-sided sticky pads.
Do I need to worry a lot about heat dissipation? I think I should try not to insulate the underside or block air holes there. Orienting the PC vertically ought to be a good thing, no? Indeed, isn't that the way that ZyXEL went anyway, with the later B10D?
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The 1312 has wall mounting key holes on the underside. Fixing with sticky pads should work but not an ideal permanent solution but in your situation would have to suffice as I understand it.
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I will ask Mrs Weaver what she prefers. She has a powerful electric screwdriver called Walter, and loves any excuse to use it. Walter saves her from all pain in her arthritic hands.
The only problem I foresee with the screw heads method is that of change in the future. If you change to different kit, then you might end up making a mess of the wall by having to make new screw holes in the plasterboard so it ends up a mess. I suppose one way around it would be to put up a mounting board and then screw screws into that, so that if spacings need to change then a fresh mounting board could be put up in place.
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LOL Walter. Mounting board sounds the way to go if Mrs Weaver feels comfortable with that. ;)
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Mrs Weaver is giving me pain relief and making coffee, what a hero. She says she will go the velcro route.
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What a good nurse you have. I also have MH probs and a physical disability but am reasonably mobile. I dont have a nurse though so self medicate.
I hadn't thought of sticky velcro pads sounds like the best solution in the circumstances.
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I have CFS/ME and undiagnosed neuropathic pain for which I am taking a couple of neuro drugs and Fentanyl patches which have just gone up a lot in strength. More drugs for nausea, itching and dizziness to counter the other drugs.
Just now they have told me I had testicular cancer and then told me I haven’t. I am anaemic for some reason. A new doctor is freaking out because my blood pressure is exceptionally high and he says that is the cause of some of the pain and feeling horrible.
This is more than a tad off-topic, belongs somewhere else, or even nowhere at all. But it might help some kitizens understand what I can do and what not and so explain my odd choices.
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Burakkucat has pointed out to me that all I need to get rid of the SSFP is the telephony-only front part of an NTE5c, instead of the one meant for DSL. So I have bought one from eBay. Cannot get just the front part so I had to buy the whole thing, but they cost nothing anyway.
That plus the right cable, of course - one that terminates in a BT431 plug.
And now no domestic dismay due to ugliness of a frontless NTE5.
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Tandy VDSL Cable 1m (twisted cable) (max speed 89Mbps / 25Mbps) (line attenuation 11.5dB)
VDSL Band Status U0 U1 U2 U3 D1 D2 D3
Line Attenuation(dB): 2.3 13.1 21.8 N/A 6.9 16.3 27.2
Signal Attenuation(dB): 2.3 12.4 21.0 N/A 9.1 16.1 27.2
SNR Margin(dB): 15.7 15.3 15.2 N/A 7.4 7.6 7.4
Transmit Power(dBm):-14.0 -30.1 0.9 N/A 8.1 7.9 7.0
Tandy VDSL Cable 0.50m (twisted cable) (max speed 90Mbps / 26Mbps) (line attenuation 11.4dB)
VDSL Band Status U0 U1 U2 U3 U4 D1 D2 D3
Line Attenuation(dB): 2.5 13.0 20.0 N/A N/A 6.8 15.5 25.8
Signal Attenuation(dB): 2.5 12.1 19.0 N/A N/A 8.8 15.4 25.7
SNR Margin(dB): 16.8 15.2 15.2 N/A N/A 8.3 8.2 8.2
TX Power(dBm): -15.1 -30.2 -0.7 N/A N/A 8.1 7.9 7.0
Shortern cable are best for VDSL at 0.50m but I haven't try 0.25m yet
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Unless the longer cable was actually picking up interference, it will make zero real-world difference.
The results you've posted scream "margin of error" in the reporting to me. I've seen bigger differences on my lines from a single resync and no wiring changes.
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> scream "margin of error" in the reporting to me. I've seen bigger differences on my lines from a single resync and no wiring changes.
Fraid so. That’s my experience too. Would have to repeat a lot of times.
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> scream "margin of error" in the reporting to me. I've seen bigger differences on my lines from a single resync and no wiring changes.
Fraid so. That’s my experience too. Would have to repeat a lot of times.
By which point DLM would kick in, destroying your experiment.
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Tandy VDSL Cable 1m (twisted cable) (max speed 89Mbps / 25Mbps) (line attenuation 11.5dB)
...
Tandy VDSL Cable 0.50m (twisted cable) (max speed 90Mbps / 26Mbps) (line attenuation 11.4dB)
...
Shortern cable are best for VDSL at 0.50m but I haven't try 0.25m yet
Generic presumably ~2m (didn't measure) flat Cat. 5 RJ11:
Max: Upstream rate = 64641 Kbps, Downstream rate = 369377 Kbps
Bearer: 0, Upstream rate = 50005 Kbps, Downstream rate = 329819 Kbps
Link Power State: L0
Mode: G.fast Annex A
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 5.2 8.5
Attn(dB): 28.0 0.0
Pwr(dBm): 0.0 3.9
Belkin "Hi-Speed" F3L900CP1.8MWHS (1.8m) RJ11:
Max: Upstream rate = 67483 Kbps, Downstream rate = 405028 Kbps
Bearer: 0, Upstream rate = 49965 Kbps, Downstream rate = 329867 Kbps
Link Power State: L0
Mode: G.fast Annex A
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 8.1 8.9
Attn(dB): 29.4 0.0
Pwr(dBm): 0.0 4.1
Both using NTE5C.
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Kitz Equipment Testing Procedure (KETP) :
https://forum.kitz.co.uk/index.php/topic,15905.msg307641.html#msg307641
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Kitz Equipment Testing Procedure (KETP) :
https://forum.kitz.co.uk/index.php/topic,15905.msg307641.html#msg307641
Does shielded cable REALLY make any difference, if its not grounded?
I know on ethernet its recommended to NOT use it unless both ends are earthed. But then the main reason for STP is to block mains EFI where sending it to ground would obviously complete the circuit.
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I know on ethernet its recommended to NOT use it unless both ends are earthed.
https://forum.kitz.co.uk/index.php/topic,26318.msg441458.html#msg441458
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https://forum.kitz.co.uk/index.php/topic,26318.msg441458.html#msg441458
I made a mistake there, its only grounded at the switch. I should have known better as I actually have two for my Ubiquiti LiteBeam PtP dishes where its grounded at the PoE injectors.