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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

Andrew
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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
julie_m
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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

Quote:
Originally Posted by julie_m View Post
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.
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
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
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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