Kitz Forum
Broadband Related => Telephony Wiring + Equipment => Topic started by: sheddyian on March 23, 2016, 07:14:34 PM
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A friend with ADSL is on a long line, resulting in fairly slow synch speeds (circa 6,000 - not bad I suppose).
Their internal phone wiring is minimal, there's only the one master socket, into which a filter and the phone and the router are plugged in.
I'm guessing the answer to my question is "no, you idiot!" but I was idly wondering - is there anything to be gained (performance/speed wise) from fitting a VDSL filtered face plate there? Given my assumption that there's more in them than in the usual plug-in filters, and (perhaps?) they're of a general higher quality overall.
Thanks
Ian
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How much of an improvement you get depends on the quality of the microfilter you've got already of course. But anyway the BT faceplates are very high quality so you should go for it,
The ADSLNation faceplate filter is a very good device too, recommended if the phone is causing problems de-stabilising things.
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I would add to Weaver's reply by suggesting that an experiment with, say a Mk 3 SSFP, would be the only way to obtain a definitive answer.
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Thanks, I may give it a go. I was tempted to do so anyway, but then I saw the prices seem to have gone up on ebay somewhat since I last bought one - I had it in my mind they were in the region of £5? I saw £18 for a complete lineboax + vdsl set, or around the £9 mark for the vdsl plate alone. Maybe I misremember.
Anyway, having seen the cost of buying one on a whim, I thought I'd ask the question here to see if the tinkering was worth it.
[of course, tinkering is always worth it!]
I took a snap of the router stats summary, any thoughts on these :
ADSL mode G.DMT
UP DOWN
Line Speed 896 6624
Attenuation 25.0 37.5
S/N Margin 7.0 6.0
The Kitz max speed calculator with that attenuation suggests 7328 for dslMAX or 10656 for adsl2+ :-\
Ian
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Here are two eBay suppliers offering SSFP Mk 3s at a far more reasonable price (£4-50) --
http://www.ebay.co.uk/itm/GENUINE-BT-Openreach-MK3-VDSL-faceplate-/172120365457
http://www.ebay.co.uk/itm/GENUINE-BT-Openreach-MK3-VDSL-faceplate-/191832928875
My immediate thought is to suggest using ADSL2 (G.992.3) mode rather than G.Dmt (G.992.1) or ADSL2+ (G.992.5) modes . . . assuming that the modem/router can be so configured.
[G.992.3 is the mode of choice both in Weaver's croft and The Cattery. ;) ]
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Here are two eBay suppliers offering SSFP Mk 3s at a far more reasonable price (£4-50) --
http://www.ebay.co.uk/itm/GENUINE-BT-Openreach-MK3-VDSL-faceplate-/172120365457
http://www.ebay.co.uk/itm/GENUINE-BT-Openreach-MK3-VDSL-faceplate-/191832928875
although there's then postage of £3.90 or £3.25.. I didn't remember the total being that high in the past. Had a vague memory of buying complete linebox + vdsl plate for around £10 including delivery in the past. I'm being picky, I should just order one.
My immediate thought is to suggest using ADSL2 (G.992.3) mode rather than G.Dmt (G.992.1) or ADSL2+ (G.992.5) modes . . . assuming that the modem/router can be so configured.
[G.992.3 is the mode of choice both in Weaver's croft and The Cattery. ;) ]
The router is a fairly recent cheapy TalkTalk one with only 2 LAN ports on the back, but I'm unclear on the model number. I'm assuming it's set up out-of-the box so would imagine it's trying different modes before settling on G.Dmt as best choice for the line?
I'll certainly try forcing it into ADSL2+ mode though, and see what happens.
Ian
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Just to add...
Earlier, for a few minutes, I had the brilliant idea of leaving a Raspberry Pi there, running routerstats that I could then monitor remotely to see how the line behaves, look at tones etc.
Then realised there's no way the TalkTalk router is going to have telnet enabled, is there? >:(
Ian
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The ADSLNation faceplate filter is a very good device too, recommended if the phone is causing problems de-stabilising things.
This was the first faceplate I had; later changed to a BT MK3 when I was trying to limit the effects of once or twice weekly 1-2 hour bursts of REIN from what I assumed to be a faulty spare-room TV nearby. (It eventually went away on it's own, presumably the TV died).
The ADSLNation faceplate worked well for me, in eliminating ADSL noise from voice. Even with two plug-in filters in series, there was some ADSL noise still present on the phone, the ADSLNation plate resolved this.
Later, I discovered there was an unbridged tap that was probably contributing to the audible noise on voice.
One quirk I did notice, and Burakkucat may remember, is that I found I got better signal to noise margin or attenuation rates (I forget which) with certain RJ44 leads over others, and it was repeatably consistent. There was a particular lead that always performed better, even though, spec wise, it wasn't especially good.
I later found out this was an affinity caused by the ADSLNation plate; once I'd changed to the BT MK3, I could see very little difference in reported performance between different RJ44 leads.
Ian
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I'll certainly try forcing it into ADSL2+ mode though, and see what happens.
No. :no: Not ADSL2+ (G.992.5) but ADSL2 (G.992.3)!
However if it is the usual TalkTalk supplied bottom-of-the-reject-pile device, it may only have two configurable modes -- off or sort-of on! :D
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I somehow sense that your quest for telnet access to the TalkTalk supplied device will be in vain.
On the subject of leads, yes I can remember you finding one that consistently performed better than any of the others. If I am remembering correctly, it was a give-away lead that cost less than 2p to manufacture. (As the time is now silly o'clock in the morning, I'll take your mention of "RJ44" to be RJ11 (or RJ12).)
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I somehow sense that your quest for telnet access to the TalkTalk supplied device will be in vain.
On the subject of leads, yes I can remember you finding one that consistently performed better than any of the others. If I am remembering correctly, it was a give-away lead that cost less than 2p to manufacture. (As the time is now silly o'clock in the morning, I'll take your mention of "RJ44" to be RJ11 (or RJ12).)
Yes! As I typed RJ44, I knew it sounded wrong, but couldn't remember what it was. RJ11 is what it was. And, whilst the magic lead in question was a thicker-than-average RJ11 lead, it wasn't anything special, but performed better than other fancy screened or twisted or any other RJ11 leads I tried.
This difference disappeared when I moved to the BT Mk3 plate, no discernable difference between RJ11 leads.
Ian
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This difference disappeared when I moved to the BT Mk3 plate, no discernable difference between RJ11 leads.
Ian
The Mk3 SSFP has a balun choke installed it's set to unbalance and only receive the frequencies it was designed for but it's not 100% it's more like 60-75%
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Personally, I found that the grand total of:
- replacing an old LJU master socket with an NTE5a
- getting rid of the star wiring arrangement, which included a bit of not twisted-pair cable, although this bit has been re-connected to the front plate of the NTE5a using the spare green pair in the existing cable
- fitting an Openreach MK2 SSFP (which was the one more readily available at the time I bought it)
- using a CAT5e modem lead
made virtually no difference whatsoever to the performance and behaviour of my line.
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This difference disappeared when I moved to the BT Mk3 plate, no discernable difference between RJ11 leads.
Ian
The Mk3 SSFP has a balun choke installed it's set to unbalance and only receive the frequencies it was designed for but it's not 100% it's more like 60-75%
Ah! I see! I think ???
So the balun choke is there to negate wiring discrepancies / imbalances? This might be helpful on a long line?
Ian
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- replacing an old LJU master socket with an NTE5a
- getting rid of the star wiring arrangement, which included a bit of not twisted-pair cable, although this bit has been re-connected to the front plate of the NTE5a using the spare green pair in the existing cable
- fitting an Openreach MK2 SSFP (which was the one more readily available at the time I bought it)
- using a CAT5e modem lead
made virtually no difference whatsoever to the performance and behaviour of my line.
I've tidied up a few wiring setups, especially where the internal wiring was poor/messy, and always seen an improvement in speeds and/or reduction in attenuation, admittedly to varying amounts.
If this particular slow-line also had lots of internal sockets, I would definately have put in an MK3 plate straight away, but as there's no other sockets I was less clear if it'd help.
It's now on order, so hopefully will arrive just after Easter and I'll report back if I see any improvements.
Ian
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> I'll report back if I see any improvements.
I'd be very interested in hearing about your experiences with it.
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I fitted the new VDSL MK3 plate last week, and got some basic stats from the router. I also changed a few settings along the way, and did some tests. Summary : it made a slight difference, but not much. And the TalkTalk DSL3680 (firmware v1.13t) possibly has a reporting bug.
Sync Attn. S/N
Setting Reported UP DOWN UP DOWN UP DOWN
============== ======== === ==== == ==== == ===
Plug in filter G.DMT 896 6560 25 38 7 6
VDSL MK3 G.DMT 896 6528 25 38 7 6.5
Force ADSL2 G.DMT 960 7424 23 37.5 7 6
Force ADSL2+ G.DMT 928 7360 23 38 8 6
auto G.DMT 928 6656 25 37.5 7 6
ADSL2 G.DMT 960 7392 23 37.5 7 6
reboot unchanged G.DMT 928 7328 23 37.5 7 6.5
worst to best results 64 832 2 0.5 1 0.5
1st test was with existing plug in filter into standard NTE5A. I then removed the filter, removed the NTE5A and remade the connections inside (seemed a touch loose) and fitted the VDSL MK3. I also replaced the router cable with a slightly better twisted pair one (original was VERY thin indeed). I squirted all contacts with contact cleaner.
Comparing the 1st and 2nd tests (before and after VDSL) you can see that this didn't really make any difference. Perhaps because I'd not waited long enough for the contact cleaner to dry, as subsequent tests showed a small improvement with the same router settings.
I then changed the ADSL mode from auto to ADSL2, as suggested by burakkucat. After a reboot, the router still reported it was using G.DMT mode - I double checked, I had set it to use ADSL2. And note the curious thing - the attenuation UP consistently drops from 25 to 23 when I've set the router into ADSL2 or 2+ mode, even though it's reporting the connection as G.DMT. When I set it back to auto, the attenuation jumps back to 25 again. So I'm unclear what mode it was actually connecting in! Router reporting bug, or actually choosing to use g.dmt regardless (but then why did the attenuation change consistently?)
So, slightly worth doing, and it looks tidier, but didn't gain much overall.
Thoughts?
Ian
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I suspect it's always ending up using G.DMT (ADSL1). ADSL1 line rates are always exact multiples of 32, ADSL2/2+ rates don't have to be. I'm not sure why attempting to change the mode appears to have had some effect without actually changing the mode that ends up being used.
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Perhaps try with a modem that is known to comply with its mode setting?
A Huawei HG610, HG612 or HG622, for example.
(In your conclusion line of the table, I see a typo for the US SNRM. You show zero but looking at the data above, it should be one.)
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Perhaps try with a modem that is known to comply with its mode setting?
A Huawei HG610, HG612 or HG622, for example.
(In your conclusion line of the table, I see a typo for the US SNRM. You show zero but looking at the data above, it should be one.)
I've corrected the typo, thanks.
I nearly took along my unlocked HG612, but felt it was going to be a bit inconvenient, as I'm using it myself! I may yet do so though. If I can find a cheap 2nd hand one, I'd leave it there with a Raspberry Pi and monitor the line for a while.. ::)
Ian