BT I-Plate Interstitial Plate

[Taz]

I've just ordered one of these:

http://www.broadbandbuyer.co.uk/Shop...ProductID=7256

It seems to disconnect the ring wire and offer some level of interference suppression to improve the quality of your ADSL line.

So, snake oil or a real benefit?

[jamin]

Not convinced of the benefit tbh.

But combined with some router lube it may make a difference!

[kopite]

THey DO work.

We got a batch of them at Zen and some staff members have been testing them. THey clean the line up big time

[Agent]

The Bell wire is a well known cause of interference on some lines. There is page explaining all the technical info, but its escaping me right now.

[Mossy]

The Bell wire is a well known cause of interference on some lines. There is page explaining all the technical info, but its escaping me right now.

http://www.thinkbroadband.com/faq/sections/radsl.html

[Agent]

Not the one I'm thinking of mate, but thanks anyway

It has measurements of noise levels etc. before and after the bell wire is removed

[moogle]

The Bell wire is a well known cause of interference on some lines. There is page explaining all the technical info, but its escaping me right now.

the 3rd wire acts as an antennae thats why, and causes the noise on the #2 and #5 wires which gives you that lower sync.

[jamin]

the 3rd wire acts as an antennae thats why, and causes the noise on the #2 and #5 wires which gives you that lower sync.

How? Ring wire is physically de-coupled from A and B leg by a capacitor. Any modem or router on the end should not even connect to ring wire.

I have seen instances where the spare pair in an installation has been coiled, resulting in tuned r.f inductance to the A and B wires. But seeing this 4 times in 12 years doesn't make it widespread.

At the end of the day, if you are that bothered then disconnect the wire on terminal 3 which should be orange with a white trace. At the very least it will put your mind at rest.

I'm not looking for a fight, but if the ringer wire really does make a difference I would really be interested as to why!

[peterb]

How? Ring wire is physically de-coupled from A and B leg by a capacitor. Any modem or router on the end should not even connect to ring wire.

I have seen instances where the spare pair in an installation has been coiled, resulting in tuned r.f inductance to the A and B wires. But seeing this 4 times in 12 years doesn't make it widespread.

At the end of the day, if you are that bothered then disconnect the wire on terminal 3 which should be orange with a white trace. At the very least it will put your mind at rest.

I'm not looking for a fight, but if the ringer wire really does make a difference I would really be interested as to why!

Well, no it isn't a decoupling capacitor - it is a coupling capacitor (or a DC blocker) - let me explain, but first I need a bit of history.

The two wire coming into the house have a constant DC voltage on them. Originally this was required for the carbon microhones in the original telephone instruments, and it was interruptions to this loop by the rotary dial that activated the exchange equipment - the uniselectors and relays, that required a relatively high (DC) current to operate - on top of that was the dial tone which was a much lower frequency than today. When you picked up the receiver, the local loop was made (where the term local loop comes from) and the line finder found the line and supplied the dial tone. Interuptions to the local loop provided the dialling pulses to operate the relays and uniselectors to complete the call.

The ringing tone was an AC voltage of about 50 Volts at a higher frequency to operate the bell in the 'ophone. These again needed a fairly high current (they were low impedance devices) and the phone had internal capacitors to block the DC from the bell, but allow the AC to operate it. Inductances blocked the ring voltage from the earpiece. Phones were supplied by the then GPO and were hard wired to the network (and the phone was rented)

With the de-regulation of the telecoms industry and the growth of electronics, customers could buy their phone and plug them in. It was necessary to break out the ringing signal at the entry point to the house, this is done by the master socket, which cantains the ringing capacitor to block DC from thebell wire but allow the AC through. Modern phones with high impedance bells or electronic ringers don't need this third wire. so we end up with a long length of wire, untermnated at one end, and the other end coupled via a capictor to the incominbg circuit (or one leg of it.

This can act as an antenna, and couple noise spikes through onto the main incoming line, which is now carrying the high frequency ADSL signal - with the potential for interference.

So the bell wire is really a legacy device, which few telephony devices need, but it is part of the4 cabling specification. in 99% of cases it can be disconnected at source - the incoming master socket - without any detrimental effect on telephony equipment, and sometimes some benefit to ADSL equipment.

This also links to ADSL filters. You don't need a filter if the modem is connected to the incoming line pair, with no other devices on it. However if you do, you need a filter. Cheap filters connect the router directly to the line and filtere out the voice signal so the ADSL line noise isn't heard in the phone, and so that the ADSL signal isn't lost when the phone is picked up.

Better filters (built to the BT spec) not only do that, but also filter (or impedance match) the ADSL signal to the router, so that telephony signalsd are removed, and that can also improve ADSL performance.

I hope that explains it.

[jamin]

Thanks for the explanation, but I know how the PSTN works (I have worked on it for 12 years)

What I don't understand is why you need to buy this plate when you could just dis the bell wire.

[moogle]

Thanks for the explanation, but I know how the PSTN works (I have worked on it for 12 years)

What I don't understand is why you need to buy this plate when you could just dis the bell wire.

I think this allows you to not have to go through opening your master socket and disconnecting the wire. I mean you've worked on it for 12 years you should know that you aren't allowed to touch the BT master socket right? Probably thats why most people would go for this. But yes the disconnecting the orange #3 wire is easier but most people wouldn't want to risk facing a charge from BT if they mess it up and then are found to have interfered with the master socket.

[james_d]

Aslong as you've got a new style NTE5 faceplate where the lower half is removable, you can do whatever you want with the bell wire as it's only connection is in the lower half. The removable faceplate is considered customer equipment and beyond the network termination point.

If you've an older master socket, then no, you shouldn't touch it. But then the i-plate will be useless aswell as it'll only connect upto an NTE5.

[moogle]

Aslong as you've got a new style NTE5 faceplate where the lower half is removable, you can do whatever you want with the bell wire as it's only connection is in the lower half.

I think you still can't access the bell wire without taking the full front plate off the NTE5 socket though.
Unless its hanging out but you won't know which is which until you see the back of the faceplate.

[james_d]

The bell wire connects on the removable part. There's nowhere for it to connect to on the NTE part, the only connections are A&B for the incoming line pair from the drop cable, and sometimes an E connection for Earth.

If all you're looking to do is disconnect the bell wire, the removable customer faceplate is all that needs removing. No need to touch the BT side atall.

[moogle]

guess it's just my faceplate then
can anyone else see their bell wire without removing the 2nd faceplate?

[kopite]

The wires should all be screwed into the back of the NTE5 socket. The only wires plugging into the faceplate are the extensions.