No ring without filter

I recently fitted an ADSL Nation filtered faceplate, so everything has improved. However, having established here that I don't need filters at extensions, I removed the filter where it was used at the BT hardwired extension. (BTW when I fitted the filtered faceplate at the master, I remade the extension wiring to the same numbered terminals on the new faceplate as in the original). I thought the extension was ok (it was certainly quieter since the new faceplate) since removing the filter the phone no longer rings. Put the filter back in and it does ring!! The phone is an old pulse dial one which used to ring just fine before fitting the filtered faceplate. The phone is fine with filter, but I'm just mystified.
Any ideas please?

Edit: BTW it's this type of filter.

Edited by rob54 (Sat 11-Aug-12 20:49:57)

When fitting the extension did you disconnect the ring wire? The older phone may need it. Filters have a capacitor in them that enables the phone to ring even if the ring wire is disconnected.

Following on from what Kr1s69 says, it is fine with the ADSL Nation XTE-2005 to connect the ring wire on T3 at each end. That's assuming you are using T2 and T5 for the extension, not the unfiltered extension A/B.

It incorporates a filter on T3.

If you are using the unfiltered A and B, then you need the extension filter anyway.

Edited by RobertoS (Sat 11-Aug-12 21:36:02)

There were three wires connected to the back of the original master faceplate as here and I connected those three to the only three numbered terminals behind the ADSL Nation faceplate. So AFAIK the answer is no.
But OK that explains why the phone rings with the filter. Maybe the ring wire connection is not good. I used a, eerm is it Krone tool, a disposable one, I bought with the faceplate.

We'll probably do away with the old phone soon so it won't matter so much.

Edited by rob54 (Sat 11-Aug-12 22:45:11)

Is the ring wire connected at the extension?

Nothing wrong with the cheapo Krone tools.

In reply to a post by RobertoS:

...If you are using the unfiltered A and B...

Irrelevant to the OP but A and B supply an unfiltered ADSL signal - does that carry the voice frequencies also? If it does, is that A-B connection OK to use for a router without filtering off the voice frequencies?

Often wondered about that with the A-B connections at the back of filtered faceplates

In reply to a post by 4M2:

Irrelevant to the OP but A and B supply an unfiltered ADSL signal - does that carry the voice frequencies also? If it does, is that A-B connection OK to use for a router without filtering off the voice frequencies?

Often wondered about that with the A-B connections at the back of filtered faceplates

The thing is, you have the opposite idea of what ADSL filters do to what is in fact the case. (Ignore the T3 ring wire as irrelevant for this discussion).

The ADSL/VDSL2 filter removes the broadband signals from the telephone connections. Not the phone signals from the broadband connection. If it didn't, you wouldn't be able to hear a darn thing on the phone. Ever heard a dialup modem connecting? Or picked up a ringing phone and just heard a high whistle? That is a modem (probably a fax) trying to connect.

Neither does a conventional filter split the two signals. It could only do that by containing two filters, one to remove broadband, feeding the phone socket, followed by another removing the phone stuff. So more than doubling the complexity of the bit of kit.

ADSL/VDSL2 sockets present everything that is on the line to whatever is plugged into them. Filtered phone sockets only get analogue audio frequencies. A modem or modem/router on a ADSL/VDSL2 filtered socket gets an unfiltered signal, including the phone frequencies which it ignores.

So the A/B connectors on the back of filtered faceplated get a completely raw signal, effectively direct from the main incoming Openreach line. Straight through - hidden main A/B >> test socket >> faceplate >> extension A/B supply.

Anything on the extension at the other end requires a filter.

Except!!!

In an installation where absolutely nothing is connected to the phone line except a modem or modem/router, no filters are needed at all. (Though if physical extensions are present but not used, their ring wires may need removing or filtering. I believe some early filtered faceplates did not filter it. It's the ring wire's capability of picking up and feeding back random electromagnetic noise that is the problem).

Edited by RobertoS (Sun 12-Aug-12 00:05:59)

Thanks Bob - as always your replies are thorough and highly informative

I think my misconception was based on the use of the term "filter/splitter" where I assumed the actual signal was split into broadband and analogue audio frequencies as two separate entities. The fact that an adsl modem/router can ignore phone frequencies means that it can be connected directly into the test socket with a telephone plug to rj11 modem lead, if I understand you correctly, and thus not require a filter which I always thought was necessary.

In reply to a post by 4M2:

The fact that an adsl modem/router can ignore phone frequencies means that it can be connected directly into the test socket with a telephone plug to rj11 modem lead, if I understand you correctly, and thus not require a filter. (which I always thought was necessary).

Correct .

For some reason I had the impression that the A-B connections on the back of a filtered faceplate were exclusively for adsl but now you have shown that they can in fact be used for an extension where both voice and broadband are required, a filter obviously being needed due to the raw signal.

Also ,as you pointed out to the OP, a bell wire could not be used if connecting an extension to A-B since only two wires are in use....interesting stuff, many thanks for the clarification

In reply to a post by RobertoS:

Following on from what Kr1s69 says, it is fine with the ADSL Nation XTE-2005 to connect the ring wire on T3 at each end. That's assuming you are using T2 and T5 for the extension, not the unfiltered extension A/B.

It incorporates a filter on T3.

If you are using the unfiltered A and B, then you need the extension filter anyway.

Interesting. Is the XTE-2005 the only one that incorporates a filter on T3? At different times I've used a faceplate filter from Clarity (probably made by Pressac) and one from Austin Taylor.

Not noticed any practical difference between them, but do either of these latter two incorporate a bell wire filter? Be interesting to know

Edited by Tacitus (Sun 12-Aug-12 11:19:13)

I don't know sorry. I only know the XTE-2005 and the current Openreach ADSL/VDSL faceplates do, and I'm almost certain I remember the OR-logo'd ordinary faceplates as well.

In reply to a post by Tacitus:

At different times I've used a faceplate filter from Clarity (probably made by Pressac) and one from Austin Taylor.

Not noticed any practical difference between them, but do either of these latter two incorporate a bell wire filter? Be interesting to know

Yes it would be interesting to know - I use a Pressac but don't connect the bell wire. I don't actually need the bell wire connected for my phone extension but if I did it might possibly cause problems?

In reply to a post by RobertoS:

I don't know sorry. I only know the XTE-2005 and the current Openreach ADSL/VDSL faceplates do, and I'm almost certain I remember the OR-logo'd ordinary faceplates as well.

I'm pretty sure the OR logo'd NTE5s incorporate a bell wire filter. Getting OR to fit one is another matter altogether, although they do appear on eBay from time to time - entirely legally I'm sure

It would certainly be useful to know which of the replacements incorporate a bell wire filter. The XTE-2005 seems to be the leader in this respect, although I'm not a big fan of active filters.

In reply to a post by RobertoS:

I don't know sorry. I only know the XTE-2005 and the current Openreach ADSL/VDSL faceplates do, and I'm almost certain I remember the OR-logo'd ordinary faceplates as well.

Just to get matters right, all filter faceplates from BT, ADSL Nation and anyother supplier, generate their own ring wire connection after the filter. They do not use the connection from the NTE-5 for other than the line pair.

In reply to a post by RobertoS:

Is the ring wire connected at the extension?

Nothing wrong with the cheapo Krone tools.

Suppose it has to be as there has nearly always been a pulse dial phone connected there even before I had broadband.
Yeh the Krone tool seemed to work well enough.

In reply to a post by RobertoS:

Neither does a conventional filter split the two signals. It could only do that by containing two filters, one to remove broadband, feeding the phone socket, followed by another removing the phone stuff. So more than doubling the complexity of the bit of kit.

ADSL/VDSL2 sockets present everything that is on the line to whatever is plugged into them. Filtered phone sockets only get analogue audio frequencies. A modem or modem/router on a ADSL/VDSL2 filtered socket gets an unfiltered signal, including the phone frequencies which it ignores.

http://www.clarity.it/telecoms/adsl_bandwidth.htm - "...sound freqencies on the line which sneak up into the chunk where ADSL is working, your ADSL modem can get pretty miffed and slow down, stall, or even lose the connection with your ISP." ???

It's badly put, that's all. (He does say it's a simplified guide).

The filter works in both directions, removing all but phone frequencies.

So for downstream the xDSL stuff doesn't get to your phone circuit, and for upstream only phone frequencies get back from the phone circuit to the exchange connection - i.e.where the xDSL is.

The xDSL circuit is unfiltered.

In reply to a post by 4M2:

http://www.clarity.it/telecoms/adsl_bandwidth.htm - "...sound freqencies on the line which sneak up into the chunk where ADSL is working, your ADSL modem can get pretty miffed and slow down, stall, or even lose the connection with your ISP." ???

Odd. If the filter removes voice frequencies from the line entirely, how would they ever reach the exchange?

In reply to a post by Oliver341:

Odd. If the filter removes voice frequencies from the line entirely...

It doesn't. It only removes any frequencies coming from the "voice" side which are high enough to potentially interfere with xDSL operation.

In reply to a post by billford:

It doesn't. It only removes any frequencies coming from the "voice" side which are high enough to potentially interfere with xDSL operation.

Yeah, that makes much more sense.

In reply to a post by RobertoS:

It's badly put, that's all. (He does say it's a simplified guide).

Cheers, it was reading that guide some time ago that lead me to believe that the voice frequencies should not reach the modem, hence they should be filtered off (blocked) even if only a modem is connected to the test socket.

In reply to a post by billford:

In reply to a post by Oliver341:

Odd. If the filter removes voice frequencies from the line entirely...

It doesn't. It only removes any frequencies coming from the "voice" side which are high enough to potentially interfere with xDSL operation.

So any devices connected to the "phone" socket of a filter producing frequencies which could interfere with the xDSL signal would have that range of frequencies blocked by the filter. All downstream frequencies would be allowed to reach the modem and the normal range of voice frequencies would be ignored. Upstream frequencies post filter would be combined and then filtered at the exchange.

So noise picked up on the line between the filter and the exchange would obviously reach the modem because it's not filtered and that could include the bell wire.

Is that about right?

In reply to a post by 4M2:

So noise picked up on the line between the filter and the exchange would obviously reach the modem because it's not filtered and that could include the bell wire.

Is that about right?

The rest of it was, I think, but this bit isn't.

The bell wire is purely a feature of extension wiring within the premises. Nothing to do with the line from the filter to the exchange. The bell wire can pick up electromagnetic noise at all sorts of frequencies because it acts as a simple aerial.

It is also connected into the circuit in a different way, via a capacitor in the master socket that creates the voltage on it to ring the extension bells. It can feed the noise back onto the line in some way. I'm a bit hazy about how, and will probably find someone with full knowledge of it steps in .

Most decent dangly filters contain that same capacitor so the bell wire is not needed when they are in use, and most modern phones also have one so it isn't an issue for them even if the user disconnects it then later moves house and leaves it disconnected. Better to reconnect it though as the new owner may have a phone that needs it, and doesn't get broadband. Or gets FTTC where again he might need the bell wire.

The Openreach normal NTE5 faceplate contains a ring wire filter, which caters for all the extensions. Older "BT" ones didn't, and it's those that the iPlate was designed for. All that does is filter the bell wire.

In reply to a post by RobertoS:

The bell wire is purely a feature of extension wiring within the premises. Nothing to do with the line from the filter to the exchange. The bell wire can pick up electromagnetic noise at all sorts of frequencies because it acts as a simple aerial.

It is also connected into the circuit in a different way, via a capacitor in the master socket that creates the voltage on it to ring the extension bells. It can feed the noise back onto the line in some way. I'm a bit hazy about how, and will probably find someone with full knowledge of it steps in .

To the layman, it is does seem odd that the bell wire should cause problems and feed interference into the circuit since it's only function is to carry voltage and is linked to the unfiltered line via a capacitor that creates that voltage. Hence any noise that it picks up, acting as an aerial, would have to travel through the capacitor in order to disrupt the adsl frequencies - I guess one would just have to conclude that the capacitor is not a filter

Edit: if I were to connect an extension to the A&B connectors on the back of a filtered faceplate (at the master NTE5) then use my own additional NTE5, complete with filtered faceplate, as an extension socket then presumably a phone that requires a bell wire would ring if connected to it. That would mean that I could have an extension that would be suitable for both a router and a phone that requires a bell wire although, of course, the length + quality of the extension between the NTE5's and the fact that I'm using two NTE5's could perhaps be detrimental to the ADSL signal?

Edited by 4M2 (Fri 24-Aug-12 04:25:32)

In fact the true reason will be even more mysterious to the 'layman'.

The reason that the ring wire causes problems is that it upsets the balance of the twisted pair carrying the broadband signal. For good transmission of the rf broadband signal and to minimise pick up of interference it is important to maintain it as balanced throughout its length. Adding a third wire via the ring capacitor means the part within the house extension wiring is no longer balanced - and as such it will pick up any common mode interference present in the house. Note that it is the main twisted pair that picks up the interference, NOT the ring wire.

(and is the reason why homeplug/powerline is notorious for radiating interference, the house mains wiring is far from being a balanced system, made totally unbalanced by wiring to lighting switches and other things. But it seems the layman doesn't understand that either...).

Post deleted by GeeTee

Edited by deleted (Fri 24-Aug-12 07:42:33)

In reply to a post by 4M2:

Edit: if I were to connect an extension to the A&B connectors on the back of a filtered faceplate (at the master NTE5) then use my own additional NTE5, complete with filtered faceplate, as an extension socket then presumably a phone that requires a bell wire would ring if connected to it. That would mean that I could have an extension that would be suitable for both a router and a phone that requires a bell wire although, of course, the length + quality of the extension between the NTE5's and the fact that I'm using two NTE5's could perhaps be detrimental to the ADSL signal?

Not a good idea. Having two master sockets in the circuit is not recommended, as it does more than just provide the bellwire connection.

Your example requires a filtered extension, such as the XTF-68/85, or other manufacturer's passive equivalent.

In reply to a post by dsergeant:

In fact the true reason will be even more mysterious to the 'layman'.

The reason that the ring wire causes problems is that it upsets the balance of the twisted pair carrying the broadband signal. For good transmission of the rf broadband signal and to minimise pick up of interference it is important to maintain it as balanced throughout its length. Adding a third wire via the ring capacitor means the part within the house extension wiring is no longer balanced - and as such it will pick up any common mode interference present in the house. Note that it is the main twisted pair that picks up the interference, NOT the ring wire.

(and is the reason why homeplug/powerline is notorious for radiating interference, the house mains wiring is far from being a balanced system, made totally unbalanced by wiring to lighting switches and other things. But it seems the layman doesn't understand that either...).

As a "layman" that would suggest to me that filtering a bell wire would not totally remove it's detrimental effect: I use a filtered faceplate (pressac) that I believe filters the bell wire but I don't connect the bell wire only the twisted pair; if the bell wire was connected then the extension wiring would perhaps no longer be balanced? Even though all three extension wires are filtered, i.e. frequencies that are detrimental to the adsl signal would be blocked from entering the circuit by the filter, that may not be totally effective in removing the bell wire's effect since it is still present?

In reply to a post by RobertoS:

In reply to a post by 4M2:

Edit: if I were to connect an extension to the A&B connectors on the back of a filtered faceplate (at the master NTE5) then use my own additional NTE5, complete with filtered faceplate, as an extension socket then presumably a phone that requires a bell wire would ring if connected to it. That would mean that I could have an extension that would be suitable for both a router and a phone that requires a bell wire although, of course, the length + quality of the extension between the NTE5's and the fact that I'm using two NTE5's could perhaps be detrimental to the ADSL signal?

Not a good idea. Having two master sockets in the circuit is not recommended, as it does more than just provide the bellwire connection.

Your example requires a filtered extension, such as the XTF-68/85, or other manufacturer's passive equivalent.

Yes it would be passive - the result though would be two locations in a premises where a phone and router could be connected to a filtered faceplate (obviously only one router would be used and not two routers at the same time.)

However you suggest that such a setup would be inadvisable since one would be using two NTE5's

I think you misunderstand that last bit .

An NTE5 is a master socket, with hidden circuitry of some sort - behind the test socket. It's duplicating that circuitry that is to be avoided.

A normal faceplate is an NTE5A to fit on an NTE5. A filtered faceplate can be fitted instead, as we all know.

The XTE-68/85 I linked to is the equivalent replacement at an unfiltered extension of a filtered faceplate on an NTE5. It replaces a standard extension phone socket with a DSL socket and a filtered phone socket, in exactly the same way as a filtered faceplate at the NTE5 replaces the NTE5A.

It is perfectly acceptable to use that sort of thing for the setup you describe. That's what it is designed for.

In reply to a post by RobertoS:

I think you misunderstand that last bit .

An NTE5 is a master socket, with hidden circuitry of some sort - behind the test socket. It's duplicating that circuitry that is to be avoided.

A normal faceplate is an NTE5A to fit on an NTE5. A filtered faceplate can be fitted instead, as we all know.

The XTE-68/85 I linked to is the equivalent replacement at an unfiltered extension of a filtered faceplate on an NTE5. It replaces a standard extension phone socket with a DSL socket and a filtered phone socket, in exactly the same way as a filtered faceplate at the NTE5 replaces the NTE5A.

It is perfectly acceptable to use that sort of thing for the setup you describe. That's what it is designed for.

Would a phone that normally requires a bell wire, connected in the extension, still ring if using the XTE-68/85 fitted to a standard extension socket where the bell wire is not used, i.e. does it contain a capacitor?

So rather than use an additional NTE5 you are suggesting the use of a standard extension socket with a XTE-68/85 faceplate fitted in the set up that I described.

However I possibly foresee (?) the unfiltered xDSL twisted pair connection from the A&B connections on the back of the master NTE5 filtered faceplate to the extension socket (fitted with a XTE-68/85) to be more susceptible to noise than a "normal" filtered voice extension from the back of the master filtered faceplate to a standard extension socket that is used for a phone only...in other words the convenience of having two locations in a premises where both a phone and router can be connected to a filtered faceplate may be outweighed by the disadvantage of having an unfiltered extension.

In reply to a post by 4M2:

Would a phone that normally requires a bell wire, connected in the extension, still ring if using the XTE-68/85 fitted to a standard extension socket where the bell wire is not used, i.e. does it contain a capacitor?

IIRC I asked them this a few years back and the answer was yes. Both the XTE-2005 and XTF-68/85 contain the same circuitry as the XF-1e.

Note - these are "active" DSL filters, not passive. I confess I don't know the difference. There seems to be a groundswell of opinion on these forums in favour of passive.

So rather than use an additional NTE5 you are suggesting the use of a standard extension socket with a XTE-68/85 faceplate fitted in the set up that I described.

Yes. That is the correct way of doing it.

However I possibly foresee (?) the unfiltered xDSL twisted pair connection from the A&B connections on the back of the master NTE5 filtered faceplate to the extension socket (fitted with a XTE-68/85) to be more susceptible to noise than a "normal" filtered voice extension from the back of the master filtered faceplate to a standard extension socket that is used for a phone only...in other words the convenience of having two locations in a premises where both a phone and router can be connected to a filtered faceplate may be outweighed by the disadvantage of having an unfiltered extension.

You a seem to be combining two different aspects there.

If you run a filtered extension for phone only you can't achieve your wish. If you use the way we have discussed that is the same as a normal installation with dangly filters at every "in use" extension, just neater.

Given decent quality twisted pair extension cable the noise fom an unfiltered pair should be minimal. That's partly what twisted pair is about. The noise created in each wire of the pair cancels out the other. Back to why a single bell wire is liable to pick up and transmit noise - there isn't anything on the other wire of the pair to cancel it.

Similarly, that's why it is essential in wiring to use a matched pair of wires, e.g. blue/white with white/blue, not blue/white with orange. The first case has self-cancellation of noise. The second has two accumulative sources of it.

Should DSL ever be available at an extension? That's a different question altogether, worthy of a new thread. My own opinion is that as long as decent extension cabling is used there should be negligible impact for ADSLx, but for VDSL2 Openreach seem quite concerned. Though they are willing to install the data extension kit to move the NTE5.

In reply to a post by RobertoS:

If you run a filtered extension for phone only you can't achieve your wish. If you use the way we have discussed that is the same as a normal installation with dangly filters at every "in use" extension, just neater.

Given decent quality twisted pair extension cable the noise fom an unfiltered pair should be minimal. That's partly what twisted pair is about. The noise created in each wire of the pair cancels out the other. Back to why a single bell wire is liable to pick up and transmit noise - there isn't anything on the other wire of the pair to cancel it.

Similarly, that's why it is essential in wiring to use a matched pair of wires, e.g. blue/white with white/blue, not blue/white with orange. The first case has self-cancellation of noise. The second has two accumulative sources of it.

Should DSL ever be available at an extension? That's a different question altogether, worthy of a new thread. My own opinion is that as long as decent extension cabling is used there should be negligible impact for ADSLx, but for VDSL2 Openreach seem quite concerned. Though they are willing to install the data extension kit to move the NTE5.

That's a great summary

RE: OR data extension kit can be up to 30 metres in length so I guess that can be considered OK...

In reply to a post by 4M2:

RE: OR data extension kit can be up to 30 metres in length so I guess that can be considered OK...

Yes, but it isn't standard CW1308 telephone extension cable. It was posted what it is, a while ago, but I didn't bookmark or note it. As I understand it, the 30m is not a maximum either. It's just the standard issue length.

Not like this http://www.clarity.it/xcart/product.php?productid=16... then?

Looks OK to me for ADSLx. Whether it is the same as is used for VDSL2 (FTTC) data extensions I don't know, but currently FTTC is single VDSL2-enabled socket anyway.

In that situation it could certainly be used to carry the ethernet output from the modem to the extension, with another pair carrying the phone connection. So the (cable) router could be at either. Making you reasonably future-proofed.

In reply to a post by RobertoS:

Looks OK to me for ADSLx. Whether it is the same as is used for VDSL2 (FTTC) data extensions I don't know, but currently FTTC is single VDSL2-enabled socket anyway.

In that situation it could certainly be used to carry the ethernet output from the modem to the extension, with another pair carrying the phone connection. So the (cable) router could be at either. Making you reasonably future-proofed.

That certainly would be my preference