Category Archives: Ramblings

Thoughts on interesting, amusing or annoying topics

Wiring a new telephone master socket

Determining that the line is live

In the previous post, I explained that BT advised me to instal a new master socket myself.  My builder had installed a 4-pair cable (probably a standard CAT-5 network cable) from the BT drop-wire to my workroom (although I have no idea where the junction box is hidden), and had pushed the white/green pair into an old socket, so I guessed these carried the line. The CAT-5 network cable is not compliant with the UK telephone standard, but no matter.  A telephone line usually only requires a single pair nowadays, although my system originally had an earth connection from an earth rod near the drop wire, but this has long since been disconnected.   Earth wires were originally installed as part of a spark suppression system in the days of long overhead wires and in some cases were used as part of the exchange-calling system on so-called ‘party’ (i.e. shared) lines.

In the idle condition, the network pair carries a potential difference of 50 v DC, with the so-called A-leg being at 0 v and the B-leg at -50 v, relative to earth.  The polarity on the pair only matters in a few special cases, but I wanted to do the job properly, so I measured with a voltmeter to confirm that the line was active and determining that the white/green wire was 0 v (making it the A-leg) and the green wire was at -51.2 v (B-leg), see photo below.  This told me which wire to put into each of the terminals.

Testing the voltage on the A and B legs of the network ‘drop wire’

It is safe to touch the wires, although always wise to avoid this for the reasons I’ve previously mentioned.  However, if someone rings the line whilst you are touching them, you will get a nasty zing, because the ringing voltage is about 75 v AC at 18 Hz.  I believe that now it is around 100 v at possibly slightly higher frequency.  So the peak voltage is √2 times this, i.e. about 140 v, and the peak-to-peak is twice that, so plenty of juice to sting you.   Remember the electrician’s mantra – keep one hand in your pocket!

The NTE-5c Mk 4 master socket
Rear of base-plate with exchange wires connected. Non-standard wire colours – see text.

The NTE5c socket is a clever piece of design. It is in three parts – a standard-sized back-box that is fixed to the wall.  Then the base plate.  The drop wire is connected to a 1-pair cam-lock connector on the back of the base plate, marked A and B. Nothing else. The Base Plate is then fixed to the back-box by two screws.  This demarcates OpenReach’s ownership from the subscriber’s, who is not supposed to remove these screws.

On the front of the base plate is another cam lock connector, this time with three terminals, marked 2, 3 and 5.  They have kept the historical numbering, even though the other wires are no longer used.  Wires 2 and 5 carry the speech  and correspond to legs A and B, whilst wire 3 is the bell wire, and separates the AC ringing current from the DC loop current by means of a capacitor.  The Master Socket also used to have a surge protector across the A and B legs.  This was a small neon tube that would discharge a potential above a few hundred volts, preventing damage to the instrument or a shock to the subscriber, but the gas-filled tube also acts as rather a noisy capacitor at high frequency and thus makes the line noisy for the broadband signal, so it is no longer fitted.  It does mean that there is less surge protection than in the past, but this is much less of an issue than in the days of miles of uninsulated lines carried on overhead poles.  [I was once in a house during a violent thunderstorm when the fuses in the drop-wire junction box blew out.]

Connection of network wires to A and B legs of master socket

You don’t need any tools to connect the wires to the camlock connector. You lift up the clear plastic tab and then, observing polarity, push both wires through the front holes, then making sure to keep them straight,  through the back holes. It’s not quite so easy to keep them in place when fitting three wires – one can easily spring back.  If the wire isn’t through both holes, it may not be properly forced between the terminal prongs when you push the plastic tab back down. I would say this is a slight issue with the camlock connector.

Having connected the network wires into the rear of the back plate, secure it to the back-box with the screws provided.

You will see that there is a socket for a telephone plug on the front of the back plate.  Plug in a standard (non-powered) telephone.  You should get dial tone (you may need to wait a few moments) and be able to make (and receive) a test call.

So your line is working! Excellent.

Connecting the extension wires
Front of base-plate with extension wires connected

Returning to the NTE5c – you, the subscriber, can connect all your hard-wired extensions to the 3-way cam-lock connector on the front of the back-plate.  However, until the front plate is inserted, there is no connection between the exchange line and the subscriber’s wiring.  Instead, if you look carefully at the telephone socket in the back plate, you will see three wires at the bottom which are not connected when inserting an ordinary telephone socket, as these have no pins on the bottom edge. However,   when you plug in the front plate, this has a special plug that connects wires 2, 3 and 5  to the terminals on the front of the back plate, thus connecting your extension wiring to the exchange line.   The beauty of this is that when the front plate is removed, the exchange line is completely disconnected from the rest of the internal wiring, so if you can’t get dial tone from the socket in the back plate, the fault must lie of BT’s side of the system.

The front plate

As I understand it, two types of front plate are available.  One just has an ordinary telephone socket on the front, and the other has a telephone socket and a broadband socket with the necessary filters being built into the front plate, as in the illustration at the top of this post.

As mentioned, the front plate has a special plug that goes into the telephone socket in the back plate, but at the same time, connects the internal wiring circuit to the exchange side of the circuit.  The front plate is kept in place by two spring lugs and can be easily removed by the subscriber.  The idea is that if your line goes down, BT can ask you to remove the front plate (no tools needed) and ask you to plug the phone into the socket in the back plate.  If this works, they know the fault is on your side of the system.  They can then charge you whatever to come and fix it, or no doubt there will be independent firms who can investigate, perhaps more cheaply.

That really is a brilliant wheeze!

Fitting the extension bell wiring
The old-style GPO telephone extension bell with original wiring

The builder had run another 4-core pair to the position of the extension bell.  So I have re-fitted the bell and connected the blue and white-blue pair to terminals 2 and 5, and the orange wire to terminal 3 on the front of the back plate of the master socket.  The extension bell solenoid is connected at the other end to blue and orange wires.  The label in the bell-box states that as connected, the solenoid offers a resistance of 1000 Ohms, which is, I think, below the presently recommended value, but has always worked well.  Possibly it may not be so happy if there were more ‘ringers’ on the circuit.  Having now tested it, it is extremely loud, so there is plenty of current at the bell.

The ringing current

On a related subject, where does the ringing current and all the other system tones come from?  In the old Strowger exchanges, there was a ringing machine at the end of each rack, basically a motor-generator set.  The generator had a number of different windings to generate the necessary tones and a cam-operated set of contacts interrupted the tones to produce the brr-brr ringing cadence.  I can remember having an argument with someone who said to me ‘The phone is ringing at the other end’ and when I said ‘how do you know’, they said ‘I can hear it’.  They just could not understand that the ringing sound they could hear was supplied by the exchange, and was not the bell at the far end!

I hope this gives you a bit of insight into the telephone system and will allow you to instal your own master socket when necessary. Take care as always when working with electricity, especially at height.

BT amazes again!

Broadband connections

Some months ago, I had to switch to mobile broadband whilst I had some building work done. Unexpectedly, the builders had ripped out all my phone wiring!

So the builders have gone and I need my connection to be reinstated.  They got rid of everything, including the phone master socket, although they’d left the extension bell box in a corner because I specially asked.  Luckily the ‘drop wire’ from the network is still there.

Putting in a Master Socket

So I looked up how to put in a Master Socket.  This basically provides a termination to the exchange line and also separates the voice line from the broadband line (through a filter circuit).  Although it’s straightforward, a YouTube video I watched (clearly made a few years back) pointed out that it was illegal to fit a Master Socket yourself.  As I’ve said before, I worked as a student trainee for Post Office Telegraphs and Telephone (as it was then) and I remembered how ‘precious’ they were about it.  In those days, of course, they owned everything including the ‘instrument’ as the phone was called.  Telephones were permanently wired in and you couldn’t fit your own. Your instrument was rented and quite often your line was shared with a neighbour! They would say things like how an idiot householder could accidentally connect the phone line to the mains and this could electrocute a technician.

So I thought, well, I have a lot of things to do in the house, so I guess I will have to bite the bullet and get BT to do it.  Today I called BT and after a long wait got through to a nice girl in Blackburn. ‘Oh’, she said,  ‘Well we could do it for you but it will cost £130.  But you could just buy a socket in a hardware store and do it yourself.’.. ‘Right’, I said, ‘But I thought that was illegal.’  ‘Oh, no.  It’s perfectly fine and easy enough to do if the wiring is still there!’

I was gob-smacked.  So I’ve ordered a very nice ‘genuine Openreach’ NTE5C socket (which probably means Network Termination Equipment’ via Amazon and will look forward to seeing how I get on.  I haven’t yet tested the voltage on the line.  If I remember right, there should be 50 v across the exchange pair as long as the line is still connected.  From experience, you don’t feel this voltage, but it goes up to 75 v (AC) when ringing and this can give you quite a thrill.

I’m going to re-fit the original extension bell box as this is audible in the garden.  Should be fun.

Wait for the next instalment soon!

More on scams

A small token of appreciation from the Windows team
A clever scam

I got an email from the address ‘engage dot windows dot com’ offering me some nice screensaver photos and various other ‘useful’ links.  This is the first time I’ve ever had anything like this, and knowing that images can contain hidden pixels that try to instal malicious code, I was highly suspicious.  Oddly, I had just updated my screensaver photo with one of my own that I particularly liked, so I wasn’t interested in theirs.  I have Googled the link and whilst I haven’t had a ‘red alert’, I think this is a very clever scam.

Probably not a scam

I had reason to make a small insurance claim just before Christmas. Yesterday I got a phone call purporting to be from my insurance company regarding ‘my recent claim’.  Almost everyone has had such a call – usually a random attempt at ‘ambulance chasing’ – they hope to get a reimbursement of their expenses when they find a susceptible person.

I’d already confirmed some of my details when an alarm bell rang – they were calling me on my mobile number but had not even attempted to confirm their bona fides.  I said to them, ‘Hang on, what is the claim number you are calling about?’  ‘We can’t tell you that , Sir, it’s data protection, you know.’  Then they said, ‘You gave us a “memorable word”.  Can you tell us what it is?’  Well, I couldn’t remember it off the top of my head, and I asked them to call me back in ten minutes.  Her reply was ‘Don’t worry, Sir, we’ll send you a letter.’

The more I think about it, the more this smells.  They had phoned me on my mobile number and asked me for personal details but had told me absolutely nothing.  Luckily I had given them nothing that wasn’t in the public domain, but it would have been so easy to let something slip.

If they were genuine, it would have been easy for them to say that it was about a claim submitted on a certain date and give me part of the claim reference number, or part of the memorable word, before asking me for personal information.  Was it, or was it not a scam?  Even if I do get a letter (and so far I haven’t), I will never be sure.

They’re tracking you!

A year ago I mentioned how the ‘General Data Protection Regulation’ had somewhat backfired – now every website want you to agree to its ‘Privacy Policy’, which is of course ‘Newspeak’ (see George Orwell’s prophetic book ‘1984’, where Newspeak is a language designed to control the way we are allowed to think) for permitting them to intrude into our most private moments.

No-one ever reads privacy policies – they are designed to be impenetrable.  But if a privacy policy doesn’t fit onto a single page, you can be pretty sure that it is giving them all sorts of rights over your private information.

What should you do about it?  One of the most intrusive elements is the ‘tracking cookie’.  This can record pretty much anything that you have done on a website, even when you’re not specifically logged in.  If you put in health questions, this can be recorded.  Then other website, such as one selling health products, can look at this and target you with advertising.

There are various apps that let you delete tracking cookies, and I consider that this is an essential housekeeping operation that everyone should do frequently.

I’m rather annoyed with eBay right now.  Although I always buy from a local shop if I can, I needed something that I couldn’t find in after trawling round the local shops.  I do sometimes use eBay and there was a product already in my list that I’d eventually got somewhere else.  So when I selected the product that I actually wanted, to my despair I saw that instead it had placed an order for the earlier product instead!  I realised that eBay had automatically logged me in and when I went to the order screen, it whacked out that order.  OK so I was not careful enough, but I am pretty careful, and if it happened to me, it happened to lots of others.  Clearly a trick to catch people who are hesitating about placing an order!

To be fair, I was able to cancel the order quite easily, but it was still rather annoying, and clearly a deliberate design ‘feature’ by eBay.

I’ve noticed that ‘Google’ is particularly bad at offering a ‘connected’ experience, which is a Newspeak word for ensnaring you in their net.

The Energy Deal Scam

I’ve been getting calls on my business line saying that my ‘energy deal’ has expired and that I need to set up a new one.

I know full well that I have recently taken out a new energy deal with Octopus Energy which I am very pleased with, so when someone phones me and immediately starts lying, the ‘Scam Alert’ sirens start up.

Then an article in ‘Private Eye’ caught my own eye.  It seems that these firms (called ‘Third Party Intermediaries’ or TPIs) say they will act as your agent to get a good deal.  To authorise them to negotiate on your behalf, you sign a Letter of Authority (LOA) which lets them set up a deal on your behalf but not to your benefit.  This is because selling to business is not regulated like selling to householders.  They set up a rigged ‘tendering process’ and take unacknowledged fees from both parties.

The next time I get a call about my energy account, I won’t be so polite.

The TripAdvisor Money Machine

Planning a short sight-seeing trip to a foreign city isn’t easy – you want to see the best sights in a short time and at an affordable price.  You don’t know your way around the city – there are so many hotels on offer, but what are they like? Are they conveniently situated? what facilities do they offer?  As soon as you start Googling, you are bombarded with websites offering you all sorts of temptations. Rather than making it easier, they make it worse.

We visited Venice for a special occasion and chose our hotel and flight through TripAdvisor.  The first misleading part is that they say they don’t charge a cancellation fee.  Maybe not, but the hotel you have booked probably does! To be fair, we managed to get a decent hotel, but it was on the mainland, rather than the island of Venice itself.

Then, of course, you want to visit some attractions.  Immediately you are offered ‘skip the line’ tours.  Neglecting the Americanism, which should be a warning, you book a tour ‘to avoid the queues which can be up to two hours long’.

When you get there, the queues are quite short and you discover that the prices on the door are really cheap, compared with what you have paid for a ‘guided tour’.

As one simple example of the tour issue, the only way to get around is by ‘vaporetto’ literally ‘steam-boat’.  They don’t tell you, but you can get a 72-hour (3-day) travel pass at any tobacconist shop (smoking does not yet appear to be condemned to the same extent as in Britain) offering unlimited travel by bus and boat, for £40 (in essence, the sterling pound has now dropped to parity with the euro).  (For comparison, a one-day travel card  from Epsom to London – a distance of about 13 miles – costs £21.70).

If you book a half-day ‘tour’ to the main Islands of Venice, this costs at least £18 per person, and doesn’t include getting to the boat, which would cost you a lot more.  Plus, if you really want to see the islands, you need a whole day.

Whilst you can walk everywhere in Venice, it’s not easy as the whole city is criss-crossed with canals – some wide, many narrow.  As a result, few of the streets are straight – you turn left and right along tow-paths, over bridges and through passages.  Moreover, the narrow streets mean that sat-nav in mobile phones is not always reliable, telling you to turn this way and that.  More than once, it told us that we had arrived at a destination when we could not see it anywhere.  Eventually, we realised that quite often we were at the back of the property, but with no obvious way to get to the entrance! This is except when a place had decided to call itself by a misleading name, so we were at the sat-nav destination, but miles from where we actually wanted to visit.   A good street map is advisable.


We know that scammers are getting nastier, and I’ve had three nasty scams this week.

The first was a short email that said something like ‘We know your password is xzxzzxz and that you have been accessing a porn site. Whilst we admire your taste, we have used your webcam to record what you were doing and we will share it with your friends and family unless you pay us $1200.  We are sure you will agree that this is a fair price to protect your reputation.’

The password (not the above!) was in fact genuine and one I had used with my BT mail when it was hosted by Yahoo.  However, I had long since changed it.  And since I have not accessed porn nor do I have a webcam, I knew the email was a scam, but it was still a shock to receive it.  Of course, I just deleted it.

The second scam was a recorded message purporting to be sent by BT from an 0800 number, claiming that my line had been used for hacking and they were going to disable it unless I replied to the message.  After ignoring it the first time, it rang back twice more.  Anyone with the vaguest knowledge of the internet would realise that this was just a new version of the call ‘from the Microsoft Service Department’, but it would have been scary for vulnerable people, who might well have ‘pressed 1’ as instructed.

The third scam was an email purporting to come from ‘WeTransfer’ from someone that I do business with, saying that he was using the system to send me a business proposal.  Although this was entirely possible, I had fairly recently spoken to him and there was no inkling in that conversation that I might get such an invitation.  So without opening the message, I responded back to enquire what it was about, and I got a reply using some Americanisms that (as rather a stickler for correct language) I could not imagine he would use.  Needless to say, I deleted it.  And since I’ve heard nothing more, I was right to do so. Even so, it seems that either WeTransfer or some other system has been hacked.

Of course, I’m often getting the obvious scams – one from a ‘very nice guy’ who kept phoning with ‘helpful investment advice’.  It was only when I said to him ‘Your office is very noisy – it sounds as though you’re calling from a Boiler Room‘ that the calls stopped!

Another variation on the telephone call scam received today.  “This is your credit card security department.  You bought an item for £600 from a foreign company.  If this wasn’t you, press 1”

Well, I know from experience that a real credit card company firstly tells you who they are and asks to speak to the cardholder by name, along with various other details.  I don’t know what happens if you do press 1.  Do you end up paying for a premium rate phone call?

The last post?

There is a very handy pillar box (letter box) outside my local parade of shops, which I often use for sending out birthday cards and business letters.  The last post went at 5.30 pm on weekdays, a very convenient time.  So yesterday I went at 4 pm to post a birthday card and I noted that the last post was shown as being 9.00 am on weekdays! In other words, they now only collect first thing in the morning!

To get a later collection, I either have to go to Epsom station, a walk of about a mile, where the last collection is just after 5.00 pm, or to the delivery office, which is well over a mile away, for a collection at 7.30 pm.  Neither of these has available car stopping places.  Yes, you’d think that there’d be parking at the railway station, but it’s all taken up by taxis unless you are very lucky.

I’ve thought for some time that the Post Office has pretty much given up on collecting and delivering mail.  My post usually arrives sometime after lunch, although this is very unpredictable.  My solicitor sent me an important document that I needed to read before I met him, but it did not arrive.  He’d missed the last post before the bank holiday, with the result that the document took six days to travel about a mile.  (I suspect that it probably travelled more like 100 miles because now they’re sent to a centralised sorting office and come all the way back from there.)

They’re putting nails into their own coffin with this approach.  OK, email and electronic media have taken over much business communication, but by no means all, as evidenced by my wastepaper basket.  But the Post Office has simply failed to respond to the huge rise in internet shopping. So many people are running small businesses that need things to be sent out, but have you tried using the Post Office to do this? Don’t bother – use a courier firm which will be quicker and likely cheaper.

I mentioned in an earlier blog that I did some training with the GPO (the government-run General Post Office) (which at that time had a monopoly on communication networks).  I was so shocked at the laziness of staff and so utterly bored by the sitting around that when I was offered a job as a graduate, I couldn’t bear to take it up.

One of my placements was in a trunk exchange which had vast racks of wiring frames about 50 yards long.  The wiring runs needed to be continually updated and the technicians were expected to do a certain number of jobs each day.  So my mentor would go through the filing cabinet of work, find the easiest job and do it. Then he disappeared to the toilet for a long time. I was sent to loiter at the distribution frame near the door and when I saw the Executive Engineer come in, I had to press a hidden button to alert the poker school to start looking like they were busy!

BT Bills

I’ve just received by BT bill and as expected by changing from quarterly payment plan to monthly total billing, I’ve gone from being in debit to being £200 in credit, plus a lower monthly payment!

My broadband speeds are 37.5 Mbps downsteam and 10 Mbps upstream. The guarantee a minimum downstream speed of 37 Mbps but say that my estimated download speed is 42 to 61 Mbps.  In fact, the street cabinet is getting on for a mile away, so I think their estimated speeds are rather optimistic anyway.  In the past I’d had a lot of trouble with reliability, but it was only when my phone rang non-stop that they looked into it and found a stray wire in a street cabinet causing an intermittent short-circuit.  Mind you, before they would look into it, they warned me of a hefty charge if the problem was in my house wiring!

Today I got an advertising leaflet from Sky that was enticingly cheap until I saw the pathetic speeds they were offering.  There is Virgin Media fibre in my street, so I checked that out as well.  I can get 100 Mbps for £49/month (after the first year discount) plus some TV channels.  Maybe I should look into this further.

A new DECT phone

I researched getting a Yealink cordless VoIP phone and transferring my existing landline number to a new ‘Sipgate’ account. The cordless VoIP phone looks to the user like an ordinary cordless ‘DECT’ phone, so would be acceptable to my partner.

However, I already have two Sipgate accounts which my partner and I use for our businesses, but in reality she uses her mobile phone for business and her Sipgate line is almost unused.  This is because it has a wired-in handset that is not in a convenient place.  So I decided that it would be better to get a cordless handset for that phone, so it is more convenient to use.  This would be cheaper, even for a high-quality handset, and would require little setting up.  If she likes the VoIP line, then I can transfer the landline number in due course.  The DECT handset can then be used either on the new VoIP line (with an adapter) or can replace one of our other ageing DECT handsets.

I did a fair bit of research and it seems that the main choice is between Panasonic, BT and Gigaset.  The BT offerings look fairly nice, but with a colour screen they are quite expensive. Plus, the ‘base’ station is incorporated into one of the phone charging bases, so has to be close to the main telephone port. As I’ve said, this is not in a convenient place.  Panasonic do DECT phones with a colour screen, but as far as I can tell, not with a separate base station.

Gigaset C570 cordless phone
Gigaset C570 cordless phone

So then I looked at Gigaset phones.  I’m not familiar with this brand, but they claim their product is made in Germany.  Their C570 model has a 2.2 inch colour screen and separate answering machine/ base station, and extra handsets (which are GAP compatible) at a competitive price, so that’s what I went for after checking out some reviews.  The price including two handsets was £99.00. They have been simple to instal, and (something my partner is very keen on) you can turn them to energy-saving mode which allows the handset radio to sleep when no calls are being made, checking in once every two seconds to see if there is an incoming call.

So far, we have been delighted with them.  The pay-back time will be more than a year compared with the BT ‘anytime call’ subscription (not counting the additional convenience of answering business calls) so we will see how it goes.

UPDATE: I decided to download the pdf manuals for the C570 so I can discard the paper ones.  I noted that they were in the ‘legacy’ section of the Gigaset website, so obviously that model has been discontinued, which would explain the good price.  Looking at their current offerings, the nearest similar one is the S850A GO.  This can do both landline and VoIP, but costs £100 for one handset. It has quite a lot of useful additional features.  Oddly, the Gigaset website doesn’t point you to additional handsets, which is a strange omission. The one on their website that looks most similar costs £50.