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Old 13th Jul 2019, 2:20 pm   #1
Riccardo Grillo
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Hi. First post here, and have already searched the forums and not fully understand the information, so please be gentle with me.

I currently have my master socket in the porch. When it was installed, the Openreach installer gave me a choice of an unfiltered socket and a filtered one. I chose the unfiltered one as I did not want my broadband hub/router in the porch. From this master, I have run extensions to the bedroom and then to the lounge. I suppose the basic problem is that I do not want my broadband router to be where the master socket is, and I do not want to run a new cable from the lounge to the master socket, so I'm looking for a workaround.

I have a GPO 706 Mk I and this was plugged into the lounge extension via a DSL splitter alongside the router and all was well until I decided to buy a new phone and put it in the bedroom.

The 'new' phone is a 706 MkIIA and is converted with diodes and 3.3k resistors from the same batch as used for my other phone and is plugged into another extension via another DSL filter.

Now when I dial from the one phone, the other phone rings quietly. For some reason the Mk IIA is more affected by the Mk1 than the reverse.

When I briefly Jerry-rigged the two phones onto the same plug, such that they shared the same DSL filter, all was well. Equally, if I remove the DSL filters and the router and just plug into the extensions (as was normal until broadband came about) all is well.

What I do not really understand is how we get around this. Since my extensions are wired in CAT 5e, could I use one twisted pair to supply the router and another two pairs to supply the phones? Essentially the CAT 5e could contain both the filtered and unfiltered cables and then each slave socket could be connected to the chosen cable cores (would require some crimps or similar behind the faceplates). Or would this not work for some reason - is a bell wire (3) a problem with broadband?

Or could I modify my filters? Add a terminal 3 in some way and remove the filter ringing capacitor, thus using the master socket as the ringing capacitor for the phones? Possibly this would mean the internet would fail when the phone rang, but then when the phone rings you usually need to answer it and the internet would have reloaded by the time I'd finished talking?

Oldcodger came up with a method that seems sound, but I failed to understand it and could not raise the issue as the thread he commented on was closed to new comments.

I can live with the bell tinkle, but worry the noise might irritate my neighbours.

Thank you for being patient with my lack of understanding.

Riccardo

I _think_ this is what Oldcodger was suggesting. Perhaps if he's still active he would clarify? Is the suggestion to remove (shock and horror!) the Openreach master socket? It might work, but I don't want to tamper with the Openreach line (though when I was young and irresponsible I probably would have done). Or have I understood incorrectly?

https://beta.photobucket.com/u/ricca...c-18541321dd35

And this is what I was suggesting, making use of the existing CAT 5e cable that has already been installed and leaving the Openreach master socket exactly where it is.

For clarification, slave faceplates 1, 3, and 4 (etc...) are connected to the phone side of the filter whereas faceplate 2 is connected to the DSL side of the filter. Behind faceplate 1, the twisted pair that supplies the DSL is crimped or spliced in some way without being connected to the faceplate; behind faceplate 2 the twisted pair and bell wires are crimped or spliced without being connected to the faceplate. Faceplate 2 is, essentially, a dedicated outlet for the router, while any other extension socket can be used with a telephone in the usual manner.

https://beta.photobucket.com/u/ricca...1-2ece9dafa08e
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Old 13th Jul 2019, 6:42 pm   #2
AndiiT
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Hi, from your post I guess that you are trying to eliminate Bell tinkle on your 706 phones when dialling on them.

In the past Bell tinkle was eliminated by the introduction of a third wire which with the advent of ADSL could cause problems with your broadband service additionally the need for an ADSL filter could complicate matters in the event of you wanting to use older style telephones which required a third wire for ringing; Most, if not all ADSL filters should contain a ringing capacitor to allow "three - wire" phones to be used although these may also cause bell tinkle when using older phones such as 706 types.

If you can obtain a couple of auxiliary gravity Switches 19B - 1, which occasionally crop up on eBay you could re - wire your 706's to "two - wire" working and connect the switches to mute the bell motor when the handset is lifted which should eliminate bell tinkle, this was done officially on some of the GPO's extension plan installations.

Regards

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Old 13th Jul 2019, 9:04 pm   #3
winston_1
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Don't think that would work. You still have 2 two wire phones with no means of eliminating bell tinkle on the other.

Old Codgers idea though is great as all the phones are 3 wire after the master socket after the filter. However there is no need to remove the Open Reach master socket. With a filter plugged into it the internal capacitor does nothing so it can be left in situ.
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Old 13th Jul 2019, 9:30 pm   #4
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Andi,

Thank you so much for your reply, but I wonder if we aren't talking at cross purposes?

The bell tinkle noise comes not from the phone I am dialling on but from the other phone that is not being dialled on. One phone dialling causes the other to ring.

Yes, the filters do not have a third wire on their plugs, but they do have a third wire on their sockets so the phones can ring. My understanding is that the phone and its related filter (together) are essentially running as a two-wire device in that the filter only has 2 and 5 on the plug to the wall socket but that, instead of using its own capacitor, it is using the capacitor built into the filter. Essentially the filter is converting the 3-wire phone back to 2-wire?

I had heard of adding an extra switch, but I cannot see how this would work in the context of ADSL filters if this merely mutes the bell on the phone that is being used to dial out. What I'd need to do is mute the bell on the other phone, as it is the other phone that is ringing. Can you explain what you are thinking please as I'm not sure how I'd wire the bell, or how it would help in electrical terms?

Of course, the simple thing would be to run an extra cable from the router to a splitter plugged into the master socket, but that entails running an extra cable and more holes in the building.

I had a chat with a friend who used to do a lot of work with data cables and he said he wondered what the issue was with the 3rd wire is and whether it would only cause a problem when the phone rang, which I could happily live with.

In practice, my extensions all have the third wire and so it is presumably normally at -48V and would become highly charged when a ringing voltage is applied and cut to wires AB, but since no phone is connected to that wire, there is no current.

Any thoughts on my original suggestions above?

I have also had another thought. If the issue with having a bell wire is that it takes its negative from 2(B) at the master socket and dumps its positive back onto 5(A) thus meaning that the AB pair is not balanced and that the bell cable is not balanced at all, would it somehow be possible to add a 4th wire (4) (that lovely spare green wire) to take the positive from the bell in the phone and connect to 5(A) at the master socket straight through the filters?

Thus:

https://beta.photobucket.com/u/ricca...a-614b66419588

This would mean that the ringing current would run down 3, return to the master socket along 4 from whence it would continue along A, thus, hopefully, not inducing a current or unbalancing BA on the internal wiring.
I'm guessing the reason they don't already make filters like that is that most phones would not work on them... but we can modify a 706 quite easily.

What do people think?
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Old 13th Jul 2019, 10:14 pm   #5
Dave Moll
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Default Re: Two DSL filters, two 706 phones, bell tinkle

The only simple way to eliminate the bell tinkle on the other 'phone is to have the two bells connected in parallel (hence the third wire). When dialling, the local bell is shorted out by contacts in the dial that are activated whenever the dial is in a position other than at rest (the dial-off-normal contacts). Unless the remote bell is connected via the third wire to these contacts, it isn't shorted out and will tinkle as the DC line current is alternately increased and decreased by the loop-disconnect dialling - looking somewhat like the AC ringing current used to sound the bells on an incoming call.

You say that you have additional wires available in the wiring between your sockets. If you connect your internal wiring to the output of your ADSL filter (including the third wire) this should solve your problem. Do not use any further filters on your extension sockets. You can then, if you wish to keep ADSL separate from the 'phones, use a separate pair to a socket for your router.
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Old 13th Jul 2019, 10:21 pm   #6
Riccardo Grillo
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Hi Winston,

I take it you mean Andi is effectively leaving it with 2 2-wire phones? I would agree.

Agree with you that the Openreach master socket could very well stay, but not sure what the need is for a second master socket in my diagram based on Oldcodger's post. I'm fairly sure I've not drawn what he described here

https://www.vintage-radio.net/forum/...08&postcount=8

accurately. Since a splitter contains a ring capacitor, then it's doing the same thing and it is illogical to wire as per my diagram, and I get the impression Oldcodger would not have made this mistake. If Oldcodger is reading this, can you please put me straight?

My main question is whether I can possibly run both the filtered and unfiltered sides of the split phone line down different cores of the same Cat 5e cable and have it work?

Hi Dave,

The fact that when both phones are connected to the 3-wire extension system without the filters, or are wired to the 3-wire output of the same filter, there is no tinkle shows that what you say is right and that the phones are not inherently faulty.

I think I'm starting to understand how it all works and it is reassuring that your explanation agrees with the limited understanding I am starting to gain.

I suppose the making and breaking of the contacts as a result of pulse dialling has the same effect on the capacitor in the next filter down the line as the pulses of a ringing voltage and, hence, the filter's capacitor creates a weak 3rd-wire current which causes tinkle.

We are on the same page: one single filter for all the phones is what is needed!

So, just to be sure, are you suggesting:

1. I leave my extension socket in the lounge wired to the master socket on one twisted pair (no bell wire is required: it may as well not have one).

2. Into this I plug my splitter.

3. I plug the router into the RJ11 output socket on the splitter.

3. I put a second secondary socket on the wall near the one that has the splitter plugged into it and wire this socket 3-wire style to any other secondary sockets using some of the remaining 6 cores in the existing cable.

4. I get a double male extension cable and plug one end into the secondary socket I fitted in point 3 and I plug the other end into the BT431 output socket on the splitter.

If that is what you are suggesting, it seems like a winner to me. Is that, in essence, what you meant?
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Old 14th Jul 2019, 10:51 am   #7
WayneL74
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Hi Riccardo.

There is another method you could try which won't involve changing any of your internal wiring.

I have a Planset N625 wired with 2 "external" extensions. These extensions are 2-wire 706 phones effectively wired in parallel.

What the GPO did to eliminate bell tinkle on those was fit a thermistor in series with each bell coil. This causes a slight delay with the phones start to ring (about 1 second) but does stop bell tinkle.

The device you are looking for is a Thermistor 1A-1. These are available from eBay and other GPO spares suppliers.

You would wire it in place of the strap across T4 & T5 is each 706 telephone. You may already have a resistor in place of this strap. If so then post a picture of the wiring of your phones and I can advise how it can be done.

Hope this helps.

Regards,

Wayne

Last edited by WayneL74; 14th Jul 2019 at 10:55 am. Reason: Spelling mistake
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Old 14th Jul 2019, 1:39 pm   #8
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Default Re: Two DSL filters, two 706 phones, bell tinkle

The easiest solution probably is to replace the faceplate of your NTE5 with a "whole house filtered" version. This has an RJ11 for the ADSL router and an RJ431 for the phone, plus the usual Krone terminals for extension wiring. Everything on the voice side is filtered, and it has a 1.8μF ringing capacitor which will supply a total REN of 4. You can then keep all your voice circuits as three-wire.

The only downside is, your router then has to be near the master socket. But this is less of a problem anyway, if it is used wirelessly.
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Old 14th Jul 2019, 3:00 pm   #9
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Hi Julie,

That would be ideal, were it not for the fact that I cannot have a router in the porch as it would not be central for wireless (in practice, I don't use wireless). Not only that, but, while there is an electrical socket in the porch, it is on the other side of the entrance door. I have tried this location for the router and it is a terrible solution in this specific house.

You make a good point about the capacitor though. The filter only has a 1 micro-Farad, which may then, as you imply, have a REN of less than 4, so I may need to remove my bodge and do it again with a filtered faceplate, once my experiment with running unfiltered BB and phone down different twisted pairs in the same piece of cable has been comprehensively tested and if it works without interference. In the meantime, it is enough for two phones.
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Old 14th Jul 2019, 3:15 pm   #10
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Quote:
Originally Posted by WayneL74 View Post
There is another method you could try which won't involve changing any of your internal wiring.

I have a Planset N625 wired with 2 "external" extensions. These extensions are 2-wire 706 phones effectively wired in parallel.

What the GPO did to eliminate bell tinkle on those was fit a thermistor in series with each bell coil. This causes a slight delay with the phones start to ring (about 1 second) but does stop bell tinkle.

The device you are looking for is a Thermistor 1A-1. These are available from eBay and other GPO spares suppliers.

You would wire it in place of the strap across T4 & T5 is each 706 telephone. You may already have a resistor in place of this strap. If so then post a picture of the wiring of your phones and I can advise how it can be done.
Hi Wayne,

I love your way of thinking and that was the sort of suggestion I was hoping for on this forum. Thank you!

But I've already solved the problem, I think.

I've taken A and B via the orange twisted pair to my lounge socket from the master, using 2 and 5 and not connecting to 3. I discovered that the connexions on the splitter actually let the broadband run straight through. While this doesn't necessarily mean that broadband does not need a filter, it does mean that it can presumably go on the unfiltered side of it, and it seems to be working if this message gets through to people.

Behind the bedroom extension socket, I spliced the orange wires. On the extension faceplate, I've wired the blue and green wires to serve as the line and ringing pairs.

As a cheapskate alternative to buying a filtered socket or faceplate for my 5C master socket (I hate this master socket anyway), I've hardwired my filter into the 2 and 5 at the master socket and soldered my internal phone extension pairs (blue and green pairs) onto the filtered outputs of the splitter (2=blue, 3=green stripe, 4=green, 5=blue stripe). The green and blue stripe wires are soldered together as they leave the splitter so they are both 5 really. I'll stick it in an enclosure under the master socket.

So any 3 wire phone can be fitted in the bedroom and its bell will take the negative from 3 and its positive from 5.

But on a 706, I have tried to do better than that: strap T16-T17 (it isn't doing anything anyway) was removed. The strap was then parked on some spare terminals (I used T11-T12). Then I moved the green wire on the line cord from T15 to T16 so that the orange wire from the bell coil is now connected to it instead of to the white wire. This way, when the bell rings, the ringing current will be in a twisted pair and hopefully the broadband will not suffer interference.

Now all I need to do is use some of the remaining slack in the cable in the lounge to fit a new extension socket for the phone in the lounge onto the green and blue pairs.

You may be wondering how I connected my modem, which has an RJ11 plug. Well, actually, I used a spare filter. Since we've established that the filter allows the broadband to pass straight through, it's pretty much just being used as a plug adapter. It would be better to buy a different lead for my router, but if it works it'll do... so long as nobody plugs a phone into it.

As Julie has pointed out, the filter doesn't have a full-size capacitor, but it will ring two phones, which will do for now. Another disadvantage is that the socket on the master faceplate remains unfiltered and thus unusable.
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Old 14th Jul 2019, 3:17 pm   #11
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Move the master socket or install the router there and CAT6 it out to a network switch somewhere convenient. Either is an easy single cable routing job and gives you the manyfold benefits of the master filter.

In fact moving the master socket further up the chain can be done with the existing cable feeding the secondaries.
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Old 14th Jul 2019, 3:30 pm   #12
Riccardo Grillo
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Thumbs up Re: Two DSL filters, two 706 phones, bell tinkle

Quote:
Originally Posted by Scimitar View Post
In fact moving the master socket further up the chain can be done with the existing cable feeding the secondaries.
That is the winning comment on this thread. It addresses the main issue which is whether one piece of CAT 5e can run both the incoming line and the secondaries, which was something I was concerned wouldn't work. But it does, as you say, and as I'm now experiencing.

Thank you.
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Old 21st Jul 2019, 8:52 am   #13
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Default Re: Two DSL filters, two 706 phones, bell tinkle

I have used a quadrac in series with the phones like described in these circuits http://www.epanorama.net/circuits/tele_privacy.html

If you do not want the privacy function, just put it in series with the ringer.

dsk
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Old 21st Jul 2019, 2:55 pm   #14
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Hi dagskarlsen,

Your link made very interesting reading, and if I had the time, it would be the sort of thing I might want to play with - but who am I kidding? Still, it is nice to have it on here for reference.

Interestingly, when I finally went into my loft to look for a spare electrical enclosure to put my filter in, I found an old linebox-type BT master socket Virgin Media had fitted to this house on the day they presumably took away the previous BT linebox and left the cut line under the carpet and that I (annoyed at having to pay Openreach to fit a new master socket when the old one was removed by Virgin Media) had taken off and removed the Virgin Media wiring back to the ugly grey box outside my front wall.

Given that the smaller capacitor on my DSL filter did result in the ring being a a tad hesitant on one of my phones (one of the bell coil securing screws is missing and this makes it hard to adjust the bell accurately), I decided to use this spare master socket.

So I still have the Openreach 5C master socket at the end of the Openreach line (new a year ago and already the contacts between the faceplate and the socket are not entirely reliable, and why it has those awful click-in plastic capped IDC terminals instead of the usual kind of IDC ones is beyond me: they are terrible).

Into the extension terminals 2 and 5 of the Openreach master socket I have wired my orange pair - an unfiltered pair to the router extension in the lounge. Also a spare offcut pair, soldered onto the unfiltered side of the DSL filter circuit board is wired to this same pair of terminals.

The filtered side of the DSL filter is fed to the A and B inputs of 'my' internal master socket. Then the blue pair is fed to 2 and 5 and the green pair is fed to 3 and 5 on the extension side of my internal master socket and these cores are fed to my telephone extension sockets.

https://beta.photobucket.com/u/ricca...d-75fb0069bc12
https://beta.photobucket.com/u/ricca...4-74fc4e019203
https://beta.photobucket.com/u/ricca...0-f88a5964b38d


So now, if I understand Oldcodger correctly (from various threads), I think he DID intend a system very close to what I have ended up with here. Leave the Openreach master socket where it is. Wire an extension in a convenient location _using two cores only_ but otherwise in the conventional way, plug in a DSL filter to your extension socket, plug in your router to the DSL filter and then plug your own internal master socket into the DSL filter. Any internal extension you may require can be connected to the output terminals of your internal master socket.

Using your own master socket to provide the ring capacitor instead of using the one inside the filter ensures you have the 1.8 microFarad capacitor to allow you to ring multiple phones better. So there _is_ sense in using a master socket after the DSL filter if you have multiple phones and phones require a traditional 3-wire installation.

Thank you all for your help. I feel I have learnt a lot doing this.
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Old 21st Jul 2019, 11:10 pm   #15
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Ricardo- diagram of how I do it
hOPE IT MIGHT HELP OTHERS
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Old 21st Jul 2019, 11:33 pm   #16
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Brilliant. Yes, got it. We did (eventually) mean the same thing.

Although your drawing makes more sense than my attempt at a drawing this morning (which ended up in the recycling).

Thanks again!
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Old 22nd Jul 2019, 7:15 pm   #17
Tim
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Default Re: Two DSL filters, two 706 phones, bell tinkle

The combination of filters and 706/746 phones may have increased your "ren", because, as already stated ADSL filters have the bell ringing components in.

Actually they shouldn't really be called ADSL filters, because the ADSL isn't filtered at all. It's connected straight across the line, and it's actually the phone that's filtered.
There are two coils inside, in series with each leg of the line that allow the DC and low frequency AC(audio and ringing) through but block higher frequencies. So when the handset is lifted, the ADSL cant "see" the loop through the filter coils. The ringing components are in parallel, so you should be able to remove them( in theory) without affecting anything.

BTW, both types of filtered master socket have a facility for running an ADSL(only) extension, so you could of had the hub wherever you wanted.
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Old 22nd Jul 2019, 8:25 pm   #18
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Tim,

Yes, already had one apart and seen that the ADSL goes straight through. Sadly, when (a year ago) the Openreach technician came to fit the new master socket, he offered me a choice of filtered and unfiltered and told me that the filtered version would have meant that if I did not want my router close to the master socket, I would have to have a patch lead plugged into it - no way of extending in his experience. Obviously this is wrong - you could just connect to the AB connectors where the incoming line comes in (you probably aren't really supposed to, but I doubt anyone would much care), but the extension terminals were all filtered, allegedly. In fairness, if you aren't supposed to connect to the AB incoming terminals, the Openreach chap would hardly suggest it. Not that I would - the terminals on the 5C are so bad I'd probably damage them the same way as I damaged the extension terminals.

It doesn't help when the BT website even shows a router connected via a filter with no phone installed at that socket. Only point of it is that it acts as an RJ11 to BT plug adapter.

If you see my previous post (we've come a long way since my opening post), you'll see that I now have the hub exactly where I wanted it and that I have run an ADSL only extension (albeit I made my own filtered faceplate as I was in that kind of mood).

Not quite sure how using the filters would increase REN. Could you elaborate please? Originally, each phone was plugged in via an individual filter and thus not using the master socket's ringing capacitor at all.

My feeling is that ringing capacitors that have no bell connected to them will draw no current (or, in the case of a master socket, they will only be able to pass current through the 470k test resistor and so the loss would be insignificant). Please do correct my understanding if it is wrong - it may well be.

Now I've finished, there is one filter for the whole installation and the only ringing capacitor in use is the one in my internal (not Openreach) master socket. Obviously the ringing capacitor in the Openreach socket isn't mine to remove.

I did actually remove the ringing capacitor from the filter, just to make the circuit board smaller and easier to fit behind the faceplate.
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Old 22nd Jul 2019, 10:04 pm   #19
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Ricardo- that's my preferred method, when I can site the router close to the BT master, and use WiFi in the house. In days pre WiFi, I would route the incoming line from 2 & 5 in the BT master to a socket in my den where the filter lived ( via a spare pair in my internal wiring). ADSL out to PC,and phone side connected via a master to the rest of the house wiring.
As a filter- I considered it as a black box. ADSL + AUDIO In at one end and ADSL out /Audio out on the other two.
As said n the phones, to reduce REN there is a mod which introduces a resistor in series with the bell. But there is a little mentioned addition to sockets. it's usually found on older BT systems, with a separate 50v DC feed. it's a socket with a ringing generator built in . Designed for adding an extension bell to old BT systems.
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Old 22nd Jul 2019, 10:31 pm   #20
Riccardo Grillo
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Default Re: Two DSL filters, two 706 phones, bell tinkle

Yes, my phones both have 3k resistors in series with the 2x500 Ohm coils, and they both ring well now they are on a proper master socket and not ringing off a filter capacitor. I've also heard of increasing the resistance to reduce REN (or volume?) further, but I'm happy with what I have now.

Whether this will be the case if I end up with more phones...
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