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Author Topic: Improving terminal box wiring?  (Read 10002 times)

mr-b

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Improving terminal box wiring?
« on: November 06, 2008, 02:42:37 PM »

Hi

I'd like to know whether whether there are any possible improvements to be made to my wiring - mainly because my (now disconnected) BT Biz broadband reached 6M speeds and my TalkTalk line only about 2M (both lines come in on the same external cable). I've been down the path of disconnecting extensions and swapping line filters. http://www.productsandservices.bt.com/consumerProducts/displayTopic.do?topicId=16738 says I should expect max 6Mbps.

The external drop cable is "terminated" at a BT 80A RF2 terminal box which splits off into two separate phone lines - BT Biz and TalkTalk.
However the BT Biz line seems to bypass the drop cable terminal box connections completely (why?) and crimps to the wires going to the NTE5 box directly. The terminal box doesn't look at all efficently wired (see photos).
The TT line, which is connected to the terminal box connections, goes an old style master socket.

Is there anything I can do to improve my TT ADSL line quality? Could the terminal box be causing issues? Am I limited to adding a downstream NTE5 master socket?
« Last Edit: November 06, 2008, 02:47:16 PM by mr-b »
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roseway

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Re: Improving terminal box wiring?
« Reply #1 on: November 06, 2008, 03:17:13 PM »

Hi and welcome.

looking at your pictures, the wiring looks a bit untidy but I can't see anything actually wrong with it. The TT box is very close to the terminal box and doesn't appear to have any extensions wired to it, so that can't really be improved on.

I suspect that the simple explanation is that TalkTalk have put you on a 2000 kbps profile (effectively a cap) and that's what's limiting the speed. Could you copy your line stats here so that we can get a better idea about the state of your connection.
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  Eric

kitz

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Re: Improving terminal box wiring?
« Reply #2 on: November 06, 2008, 03:55:43 PM »

I too would like to see you linestats.


But.. also looking at that adsl splitter..  it looks a bit different from most filters that Ive seen.   
By any chance is that one of the new ones supplied by TalkTalk  (Fun-Jin)...  if so have a read of this
Since then Ive seen several other mentions that the filter can be problematic.  Do you have another make that you can perhaps try.
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HPsauce

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Re: Improving terminal box wiring?
« Reply #3 on: November 06, 2008, 05:24:48 PM »

BT 80A RF2 terminal box
Are you sure? :o
You need an RF3 if you want broadband to work and do actually need an RF filter.  ;)
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kitz

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Re: Improving terminal box wiring?
« Reply #4 on: November 06, 2008, 05:44:09 PM »

OMG good spot HP!

I should have spotted it from the 2 x inductors in that picture.  :-[

RF2's filter out most of the adsl frequencies and needs an RF3 fitting to work properly with adsl

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mr-b

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Re: Improving terminal box wiring?
« Reply #5 on: November 06, 2008, 08:25:09 PM »

Tx for the replies.

Yes the TT box has no wired extensions (I use normal extension leads off the filter's phone port).

Linestats:

TT stats via Huawei SmartAX MT882 modem, firmware E.37.5.5.
Standard - ADSL2
attenuation down/up 55.0/27.5
SNR down/up 15.5/15.5
sync rate 2189/339
CRC down/up 0/2
FEC down/up 3/66
HEC down/up 0/3

although just today I tried ADSL2+ and got:

Standard ADSL2+
Bandwidth Down/Up(kbps) 3659/622
SNR Margin Down/Up(dB) 6.5/6.5
Attenuation Down/Up(dB) 55.5/27.5
CRC Down/Up 12/35
FEC Down/Up 26/93
HEC Down/Up 14/178

The ADSL splitter is a new TT one but I've swapped it with multiple others (BT & TT) with no significant changes.

The comment about the RF2 terminal box is rather interesting! Any suggestions on what I should do to determine if it is really an issue? This is all an historic installation so I've no idea why it was put in that way.
« Last Edit: November 06, 2008, 08:53:58 PM by mr-b »
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kitz

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Re: Improving terminal box wiring?
« Reply #6 on: November 07, 2008, 12:19:56 AM »

RF2's were traditionally used if you live in an area nearby a large radio transmitter.  Their aim is to filter out frequencies not normally used by the (voice) telephone.
Unfortunately RF2's also filter out some of the higher frequencies in use by adsl and attenuate the line either to the point where adsl doesnt work at all, or vastly reducing the potential speed.

RF2's are often called "adsl killers".  Ezzer will know more about this, but I believe that at one point several years ago, BT were undertaking to replace RF2's with RF3s, but obviously theres still some that have slipped through the net. 

If you have an RF2 on your adsl line, BT Openreach will replace this free of charge for an RF3 (which allow the adsl frequencies to pass through).  To get it replaced, you have to go via your ISP, who need to put  a request in to BTw for removal as an adsl in compatible product on the line.
Its no good approaching BT (or your telcom provider) direct, since RF2's dont cause a problem with voice - only adsl hence why the request must go via your ISP.

Unfortunately you may hit a stumbling block as ISPs arent always aware of RF2's and the impact they can have on adsl so you may have to stand firm. 
Funny enough both HP + myself were involved in a case within the past week or so, where someone else found themselves in a similar situation to you and was having problems getting the ISP to get BT to remove it. 
In the end the ISP did put in a request and it was removed FoC by Openreach this week, gaining him a large improvement on his attenuation and sync speed.

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mr-b

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Re: Improving terminal box wiring?
« Reply #7 on: November 07, 2008, 07:07:37 AM »

That's great info and seems to explain why I'm seeing slower speeds than expected.

Re: the RF requirement, I live in Warwickshire so maybe it was due to the Rugby LW transmitters - although I'm a fair distance from there. A couple of neighbours don't have this box fitted though and which might explain why the BT line bypassed it with no apparent problems.

Will see how I get on with my ISP.
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mr-b

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Re: Improving terminal box wiring?
« Reply #8 on: November 08, 2008, 10:04:49 AM »

Well my ISP was not any help - firstly they insisted that my speed was the best possible for my line and that I'd have to complain to BT if I had any issues, and when I said that I had two lines and one had much better speeds than the other they even denied that it was possible to have have two tel lines on the same drop cable - so I decided to stop wasting my time ...

Anyway so after my local friendly ex-BT eng bypassed the offending RF2, my sync speed immediately jumped up and my download speeds have more than tripled!  ;D
Many many tx to HPSauce for spotting the smoking gun (and also to the others for their additional help)!

For comparison, my stats are now:

Standard   ADSL2+
Bandwidth Down/Up(kbps)   8123/1020
SNR Margin Down/Up(dB)   15.5/9.5
Attenuation Down/Up(dB)   29.5/14.5
CRC Down/Up   0/18
FEC Down/Up   0/155262
HEC Down/Up   0/370


(Yes the 'FEC Up' (is that a euphemism?) error count looks pretty big, but I'm happy to leave it to settle for a few days and then maybe start another thread)
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roseway

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Re: Improving terminal box wiring?
« Reply #9 on: November 08, 2008, 11:01:21 AM »

Good news (and a good bit of diagnosis by HPSauce). :thumbs:
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  Eric

HPsauce

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Re: Improving terminal box wiring?
« Reply #10 on: November 08, 2008, 11:48:06 AM »

Not really, there's a related thread on another forum that Kitz contributed loads to, and I just realised here that RF2 is the "killer" and no-one had spotted it.
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kitz

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Re: Improving terminal box wiring?
« Reply #11 on: November 08, 2008, 12:57:31 PM »

>> my local friendly ex-BT eng bypassed the offending RF2

Nice result - Those stats look pretty good now  :thumbs:

>> thread on another forum that Kitz contributed loads to

and exactly why I kicked myself soo damn hard for not spotting it in the pic in this particular case..   :no:
I think I allowed myself to get distracted by the fact that the other line worked ok through the BT connector and didnt spot the old style inductors  :-[

So all credit to HP.
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Ezzer

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Re: Improving terminal box wiring?
« Reply #12 on: November 21, 2008, 05:10:11 PM »

Don't worry about missing the rf2 on the photo, its easy when you've come accross them time after time. One of the reasons why a bt engineers head seem to spin round when first arriving on site, just checking in case of any possible clues to a problem. It's great to find an rf2, one of the easyest fixes to do and always gets a great result.

If its bypassed then that may explain the rise in fec errors, in very limited situations an rf3 can clean a line up a little for dsl purposes. but the vast majority of cases it will do nothing to improve the dsl. There is a plug in version of an rf filter called "BT Plug-In RFI Filter" item code 877596. looks like a double plug in adaptor.
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