Technical Issues for Expats: Understanding Electrics, Phones, TVs and more ...

Thanks so much for the helpful information, Paul.  I don't know where I'd be without these forums!

Jade

05xx    "Corporate" numbering, likely to cost more than a normal call.

Just a very small addition to this - 056x numbers have been assigned as non-geographic landline numbers (a confusing concept if ever there was one) - used for VoIP internet phone services, and should be charged at roughly the same amount as calls to 01x and 02x numbers now (BT charge roughly the same amount, and I believe include such numbers in their 5p for an hour etc offers - don't quote me on that though as I couldn't find the relevant page on their web site).

Other providers are more patchy; the cableco's don't route to them at all yet, but o2 (the mobile provider) consider them the same as 01x/02x.

This may be relevant for people signing up to some of the new VoIP services which provide such incoming numbers for free, while charging for 01x/02x numbers.

hth,
mark

Hi Mark, and welcome to UK-Y.

I knew I must have forgotten to mention something along the way! 

(BT charge roughly the same amount, and I believe include such numbers in their 5p for an hour etc offers - don't quote me on that though as I couldn't find the relevant page on their web site).

The standard rates as of May 2006 are  a little higher than for a regular 01/02 call. 
They're listed under the "g21" rate:

Daytime = 4.89p/min. (inc. VAT)
Evening = 2p/min
Weekend = 1.18p/min.

I'm not sure about option/discount scheme inclusion either, although they're eligible for entry into your  "Friends & Family" list.   The full details are probably buried somewhere in the tariff documents:

http://www.downloads.bt.com/pricing/UKInternationalprices.pdf

http://www.downloads.bt.com/pricing/SpecialisedNos.pdf

The tariffs have become so complex in recent years that it's becoming very difficult to keep track of them. 

It has got very confusing, indeed - colloquial evidence I've heard suggests that it's included in the 5p/hr thinger, but can't find any verification of that... and spending an hour on the phone to find out could be expensive if it's not! I suspect BT may have an ulterior motive as they are giving these numbers away with their own VoIP service.

There are some excellent VoIP packages around now, I've signed up for a $10/month package from Telasip ( newcomer link: http://www.telasip.com [nonactive] I think) that gives me an inbound US number in the area of my choice with unlimited inbound, unlimited outbound calls to that area code, and 200 minutes to anywhere else in the US. If you're reasonably technically competent (not much in the way of support for non-technically-minded people, but once it is set up it "just works"), it's a very cheap way to stay in touch with my partner and her family stateside without worrying about phone bills or running out of credit on Skype etc. I've got a small ATA box that lets me plug my regular telephone into it too, rather than faffing around with computer headsets, which I've never really got on with.

Thanks for the welcome my partner is moving over from the US in the next few weeks, I'm not just a random roaming phone (well, VoIP) geek Tons of wonderful information here (this thread and the site in general), so many things you don't notice the difference on until you start trans-atlantic-ing the whole time - took us three years until we stopped finding at least one word (or phrase) per day that wasn't the same between US and UK english, and that's just the languages!

VIDEO CONNECTIONS

There have been several queries about video connections for TV recently, so I thought I'd add some notes about the various methods of connecting equipment together.  This will involve something of a lesson in the basic principles of color television, but if you can follow these you will have a much better understanding of how the different types of interconnection work.  I'll try to keep the technical talk to the minimum necessary!

I'm sure that everybody is aware of the fact that a basic black-&-white TV picture is made up by scanning from left to right and top to bottom of the screen, adjusting the brightness of the spot on the way to make up the picture.    In the American system, 525 horizontal lines make up each frame and the scanning is repeated at a rate of 30 frames per second.   In the British system, it's 625 lines and 25 complete frames per second .   The connection for black-&-white is simple though --  Just a single signal carrying this luminance (brightness) information, plus a few extra pulses which are added to synchronize the scanning in the TV with that at the transmitter, but they need not concern us here.

Color TV adds a lot more complexity.  A color picture is made up by scanning the tube with three separate beams, one each for the primary light colors of red, green, and blue.  By adjusting the levels and proportions of these three colors any other color can be formed at a given point on the screen.  Thus to form a color picture, we need three separate signals representing the three primary colors.  

When you connect a monitor to your PC, or use the RGB (Red-Green-Blue) connections into your TV from, say, a DVD player, you are actually connecting these three signals individually.   Keeping the three color signals completely separate provides excellent picture quality, but is not practical for color TV broadcasts.  

For a start, broadcasting three separate signals would severely restrict the number of TV channels which could be fitted into the space available. When color TV was introduced an important consideration was also that there should be two-way compatiblity, i.e. that color TVs would correctly display a monochrome picture from existing black-&-white broadcasts and that existing black-&-white TVs should accept a color broadcast and correctly display the picture in the appropriate shades of gray.    That would have been impossible by changing the system to transmit three completely separate video signals.  (It would also have introduced many other technical problems, but I won't go into those!)

The overall luminance (brightness) of any given point on the picture is given by mixing red, green, and blue in the right proportions.   In other words, there is an algebraic relationship such that if you know any three quantities, you can determine the fourth.   That means that instead of transmitting separate signals for red, green, and blue, it's possible to transmit the overall luminance signal (generally symbolized as Y) plus just two of the individual color signals.   The two colors chosen are red and blue.

Black-&-white TVs use only the luminance (Y) signal to display their monochrome picture.  Color TVs take that luminance signal plus the two color signals and reconstruct the missing green color signal by simply subtracting red and blue from the overall luminance.   In very simplified mathematical terms, if  Y = R + G + B then  G = Y -  R -  B.      That also means that a color TV can show a black-&-white picture, because the b-&-w transmission has that luminance signal, just no extra color information.

Now, for various technical reasons, we don't actually transmit the red and blue signals in their original form.  We convert them to what are called color difference signals.    In other words, the red color-difference signal represents the amount by which the red component varies from the overall luminance.  The blue color-difference signal represents the amount by which the blue component varies from the total, Y.  That means that on a black-&-white picture, there are no color signals at all, since for any shade of gray the three RGB signals will always be in the same proportions.  

If you have a piece of equipment which has Y/Pr/Pb component video connections, these are the signals you are connecting:  Y is the luminance signal, representing the overall brightness.  Pr is the red color-difference signal and Pb is the blue color-difference signal.  (These connections are sometimes labeled Y/Cr/Cb instead.)

Again, connecting video as Y plus the two color-difference signals results in excellent picture quality, which is why these connections have become very common on equipment such as DVD players and HD TV sets.

Let's get back to TV broadcasting.  What we have to do is find a way to send those two color-difference signals along with the luminance signal.   We need not go into the details, but by using various electronic techniques it's possible to place a sub-carrier on the broadcast to carry extra signals.  In other words, the main signal is the luminance, or Y, signal, just as on old black-&-white  transmissions.  The color signals are "piggybacked" onto that signal in such a way that they can be separated again at the receiver, and in fact the design is such that no extra radio spectrum is taken up.  

This is where more national differences start to appear.  The original American NTSC system piggybacks the two color signals onto the luminance signal for broadcast with little change.  The resulting combined signal is then known variously as composite video, baseband video, or sometimes CVBS (which means Combined Video Blanking and Synchronization).     This is what you have on the composite video output jack of your VCR or other equipment.  

The British PAL color system uses a similar "piggyback" technique to carry the color signals, but the resulting composite video signal is not compatible with NTSC because the signals are altered in other ways first.  In basic terms, PAL is a refinement of NTSC which adds a couple of extra signals to help cancel out any errors which can result in color shifts.    

Because both NTSC and PAL were designed for broadcast use, the designs were, of necessity, something of a compromise between quality and keeping the overall broadcast signal within reasonable limits.  Both do a very good job with properly adjusted equipment, but the NTSC or PAL encoding of the color does mean that a composite video connection does not give the same quality of picture as an RGB or Y/Pr/Pb component video connection.  (Depending upon the overall quality of the equipment in use and of the source, the difference may not always be immediately apparent in all cases.)

What of Y/C (Luminance/Chrominance) connections, commonly referred to as S-video?    It's really something of a halfway house, sending the luminance (brightness) and chroma (color) information separately, but the color portion is already fully encoded to the appropriate NTSC or PAL standard.  In other words, if you took the chroma (C) portion and added it the luminance (Y) portion, you'd have composite video, and in fact it's possible to buy simple adapter leads which do just that.  

In terms of quality, S-video lies between composite and component video.  It eliminates some of the drawbacks of the combined Y/C of composite video, but because the color portion is already encoded it still has some of the limitations of  NTSC or PAL signals.    

Note that with component Y/Pr/Pb or RGB connections, there is essentially no difference between American and British standards other than the scanning rate (525 vs. 625 lines), so if the TV can cope with the different rates, the issue of NTSC vs. PAL doesn't arise.   Composite and S-video connections, on the other hand, have the color signals encoded to the approriate NTSC of PAL standard, and thus are not compatible on a TV which is not designed to accept them.

Finally,  we come to RF connections.  At the TV transmitter, the composite video signal is modulated onto a very powerful carrier signal which is suitable for broadcasting.  This is the signal you receive on your rooftop antenna and connect to the antenna/aerial socket on the back of your TV.   The tuner in the TV has to select the appropriate channel from many, then decode this signal back to composite video before passing it on to the rest of the set.  

When you connect a VCR or other source to your TV using just the coaxial antenna lead, the VCR has to simulate a TV broadcast by converting its signal to the same format.  The TV then treats it just the same as any other off-air signal and decodes it back again.  Even in the best of systems, each additional stage of conversion can add to degradation of the picture quality, and the modulators built in to most domestic VCRs, set-top boxes, etc. are not the greatest quality.   Even on relatively low-range TVs the difference between viewing via the antenna socket and via a composite or other direct video connection is immediately obvious.  

In terms of quality then, in descending order:

1.  Component Y/Pr/Pb or RGB video
2.  Y/C, otherwise known as S-video
3.  Composite video
4.  RF/aerial/antenna connection

Ideally, if you have enough component video inputs on your TV then use them for all your VCRs, DVD platers, Freeview boxes, etc.  Otherwise, you may as well use the highest quality links for the sources offering the best potential quality pictures, such as your DVD player, then use the lesser inputs for sources which have a lower inherent quality.  

You may have noticed that I've not yet mentioned the SCART connector.  That's because it's not a specific format of video connection in itself, more a physical method of implementing the connections.  SCART sockets have been fitted on British TVs since the early 1980s, and are now universal (although the number provided varies).  

The SCART standard provides both composite and RGB video connections, although not all equipment supports both and not all SCART leads are wired for both.   If you buy  a "fully wired" SCART lead, then the TV will be able to use the direct RGB video when it's available, otherwise it will use composite.  

I've not made any attempt to cover digital interfaces such as HDMI in this post, as that's getting into a whole different story.

Edited for a couple of minor typos.

To help you wade through some of the alphabet soup:

NTSC = National Television Standards Committee.   The American group responsible for defining the standards for U.S. broadcast TV.   Although the term is often used to refer explicitly to the method of color encoding used in America, strictly speaking it applies to the whole standard, not just the color.

PAL = Phase Alternation by Line.   The term refers to the method I hinted at above which is used to reduce color errors in the British system.  Phase errors in the color signals result in hue changes in the picture.  What the PAL system does is to reverse the phase of one of the color signals on alternate lines, then change it back again in the receiver.  With this reversal, any phase error in the system comes out as an equal but opposite phase error on alternate lines, and can thus be canceled out.
 
SCART = Syndicat des Constructeurs d'Appareils Radiorécepteurs et Téléviseurs.  The group which designed the SCART connector standard.   No prizes for guessing that it originated in France, and I think even the most "linguistically challenged" could translate!      You may also sometimes hear this called a Peritel connector (from Péritélévision), although the term is not used so much outside of France these days.

I should have also mentioned before that some newer equipment has added an S-video extension to the original SCART standard (which supported only RGB and composite video).    SCART connections can be very complex, because sometimes you can find a TV with two SCART sockets but only one supports RGB inputs while the other accepts S-video.  The multi-way SCART sockets provide for both inputs and outputs, but again, sometimes you'll find that one socket on a piece of equipment has both but  a second socket has only inputs or only outputs. 

The SCART connector also has some confusing automatic switching controls, enabling a TV to switch to the SCART input automatically when you switch on a VCR, DVD player, or set-top box, for example.  Unfortunately, the automatic switching can sometimes start switching things when you don't want it to!   

All in all, the SCART system can be very confusing.  It's rather ironic that when it was introduced the intention was to make interconnection between equipment easier by having just the one big cable!

Paul -

Excellent summary and follow through.  Unfortunately, I am still wary of bringing my Panasonic PT50LC13 HD LCD Projection.  The manual does not specify it can handle 625/50 but it does have two RGB inputs.  Is it possible to get HD on this TV using a non composite or DVI input?  The non-HD output does not look very good on the TV.

Chances are that the RGB inputs will display a 625/50 signal fine, but there's no guarantee. 

I tried to contact Panasonic's tech support department for another UK-Y member earlier this year with the same sort of question about a widescreen LCD TV, and unfortunately I was unable to get any definite answer. 

I just went through the manual for my Samsung LCD HDTV and it's lowest Hz for PC input is 59Hz.  I wonder if that TV will be able to display the signal.  I assumed it would have no problem before looking at the specs in the manual.

Again, there's no guarantee as it depends upon the design of the circuitry, but many modern sets will synchronize down to 50Hz even if not specifically designed for it.  Short of a definitive answer from Samsung or from somebody else who has tried with the same model, the only thing is to try it and see.  The problem with the manufacturers is that they'll often say a set won't work with a different video standard to cover themselves, even if in practice it usually will.

Syncing down for a PC signal isn't necessarily the same as syncing down for a TV signal.  PC signals have a horizontal scan rate in the region of 32kHz and TV signals in the region of 15kHz I believe, so even if it could sync down to 50Hz (vertical) for a PC signal, it doesn't mean it would be able to take a TV signal at that rate.

Another (expensive) option to consider is a modest computer with a DVI and a TV tuner to convert any TV input to a suitable DVI signal.  You can buy low-power, quiet-running media centre PCs these days which serve that purpose, and can additionally do PVR-type stuff.  Expect to pay at least 400 quid though.

PC signals have a horizontal scan rate in the region of 32kHz and TV signals in the region of 15kHz I believe

The scan rate for PCs varies between different resolution modes, but yes, for the modern VGA-type display it's around 32kHz upwards.    The horizontal scan rates for American & British TV are actually pretty close:  15.734 kHz & 15.625 kHz respectively.   Another point is that TV pictures used interlaced scanning whereas modern PC video is non-interlaced, although that's a side issue which really just reflects the timing of the sync pulses, which is determined by the source.

even if it could sync down to 50Hz (vertical) for a PC signal, it doesn't mean it would be able to take a TV signal at that rate.

Depending upon the monitor design, the "TV" inputs (RGB or component) may also not be able to take the same range of inputs as those intended for PC connection.

Telephone / Modem cables

This post is prompted by a recent query about a non-functioning modem and the confusion which can arise from the different types of cords used to connect telephones, modems, fax and answering machines to the wall outlet in the U.K.     As usual, I'll try to include just enough technical background and history to explain exactly why there can be problems.

Let's start with the American system.  I'm sure everyone reading this will be familiar with the standard U.S. modular telephone plug, seen here in its common form with four contacts:



There are various configurations for different types of telephone equipment, but the only one which need concern us for the moment is the RJ11 standard which is used to connect a basic single-line telephone (the "RJ" part stands for Registered Jack,  "11" being just part of a whole list of configurations developed by "Ma Bell" when these plugs were introduced in the mid 1970s).   

The RJ11 standard places the telephone line on the center pair of contacts of the plug.  That's the way the jack is wired on a U.S. telephone, and that's the way the wall jack is wired in your home.   The two outside contacts are most often spare (they can sometimes be used for a second line, or some other function such as dial lighting).

Now let's turn to Britain.  The GPO (soon to become BT)  developed its own type of modular connector for British phones in the early 1980s:




This also has four contacts, but the GPO/BT standard placed the telephone line on the outer pair.  You'll see why that's the root of the problem momentarily.   In contrast to American phones of the time which needed only a 2-wire connection, British telephones needed a 3-wire hookup, so the U.K. plugs also used one of the inner contacts for that third connection (it actually operates the bell/ringer).   At this time, the telephone end of the cord here was most commonly hardwired directly into the phone (i.e. non-detachable).

Move forward a few years, and we started to see phones on the British market which had detachable cords and used the American-style plug at the phone end, but because the phones needed that third wire, they were not wired to the American RJ11 standard.

If you look at the cords which are used with both U.S. and the U.K. plugs you'll see that they are flat (well, oval), with all four wires laying side-by-side.  They have to be that way to fit the plugs.    So when you put a BT plug on one end of that cord and an American-style plug on the other, the telephone line ends up on the outer contacts of the latter, not the inner pair as per the U.S. RJ11 standard.   Obviously the telephones were wired to accept the line on the two outside contacts, with one of the inside pair being used for the third wire.

O.K., if you've followed me so far, this is where it starts to get more complicated.   Over the years more and more phones sold in the U.K. have been designed to work without that third wire for the ringer, and just need a 2-wire hookup  (due in part to the fact that so much equipment is being marketed internationally now and it means the manufacturer can get away with selling the exact same phone everywhere and just supply a different cord.)

Now these phones can have the jack on the phone itself wired to the original American RJ11 standard, with the telephone line on the inner contacts.   The BT wall socket still has the line on the outer pair, of course, but because the phone now only needs two wires instead of three, a cord which has only two wires inside can be employed.  It's then possible to connect those two wires to the outer pair of contacts on the BT plug and the inner pair at the phone.

As you can see, that means that not all telephone cables which go from a BT plug to a U.S.-style plug are the same.    Use the wrong type for the phone in question, and it won't work.

Modems follow the same principles, except that they adopted the U.S.-style jacks a little sooner.  Just about all modern modems use the RJ11 standard and thus need the 2-wire cord which connects BT outer pair to modem inner pair.   Some U.K. modems from the 1980s followed telephone practice of the time and used the outer pair.  Again, if you pick up the wrong type of cord it won't work and you'll end up with "no dialtone" error messages.

The BT-to-RJ11 adapters available in stores connect the BT outer pair to the RJ11 inner pair, so if you have an American phone/modem, you can connect to a British telephone socket with one of those adapters and the original American telephone/modem cable.

RECORDS & TURNTABLES

I had a private inquiry from a UK-Y member recently related to records and turntables, so I thought I would add a few words here for the benefit of those who still use them.

American turntables may or may not be easily usable in Britain (and vice versa), depending upon the type.  The older, traditional-style units use a synchronous motor, which means that the rotational speed is locked to the supply.   Many are easily changed to 240V operation, either by a switch or by moving a couple of wiring straps inside on the motor's terminal block, but the frequency difference poses much more of a problem. 

You can change voltage easily with a transformer even if the motor is designed for 120V only, but changing the frequency is much more complex.   A 60Hz synchronous motor will run slow when connected to a 50Hz supply.  Manufacturers would normally supply a different size motor pulley for 50Hz vs. 60Hz countries.  Changing the drive pulley is the only simple way to use such a turntable here, unless you want to go to the expense of obtaining a special power unit which will convert 50Hz to 60Hz.

All direct-drive, and an increasing number of more modern idler/belt driven decks adopted a different type of motor which is controlled by electronics in the unit.  It's possible that some of these also used the supply frequency for synchronization, but mostly they use an internal frequency reference and therefore speed is independent of the supply frequency.  Such units will operate properly here so long as the voltage is adjustable, or you run through a suitable transformer.

When it comes to the actual records themselves, you will experience no compatibility problems, as speeds, groove sizes etc. are the same in both countries (and in fact, worldwide).   Strictly speaking for the hi-fi enthusiasts I should point out that there were slight differences in the equalization curves used on older records between the U.S. and U.K., but they are relatively minor and certainly no more a problem than the different EQ used between one record company and another in those times (we're talking prior to the mid-1950s here, so it won't affect more modern records anyway).

The only other practical difference you'll notice is with British 7-inch 45 r.p.m. records if you decide to collect them.  As you're aware, American 45s follow the original RCA specification and have a large 1.5-inch center hole, like this:




In the U.K., however, 45s were made so that they could be used on the standard small spindle (same size as LPs and 78s) without an adapter.  The center was generally manufactured with a piece which could be punched out easily to convert to the larger hole, like this:



This was done so that records could be loaded onto jukeboxes, which still used the large 1.5-inch size even here.  In fact many people would refer to this larger size as a "jukebox centre,"  and of course, once the knock-out had been removed one of the regular-style adapters would then be needed to use that record on a small spindle again.

Some 45s were pressed in batches, some with and some without the removable center:



Also, if you go in for collecting older 45s you might also come across the triangular knockout center, which was used by the Decca Record Co. here up until about 1960 (which at that time included not only Decca but also Coral, Brunswick, Warner Bros., London, and few other smaller labels):

CELLPHONES  & EMERGENCY CALLS

This is something I've mentioned before, but having just heard some more misinformation about this I thought it would be a good idea to re-post this warning into this thread for reference. 

***

Just in case any of you carry a cellphone around for emergency use only, be warned:

There are some stories around which suggest that you can use a cellphone here to call the 999 emergency service even if it is not fitted with a SIM card.

This is simply NOT true.

The confusion appears to arise because the GSM specification for the phones requires them to attempt a 999 call using any available network even if no SIM card is installed.   Unfortunately, none of the British network operators at present will accept such a call.

Thus if you have no SIM card fitted, you will not be able to call 999.   The phone will try to connect to any available network, but the call will simply fail with a "No network coverage" message.

Probably doesn't apply to most of you I know, but forewarned is forearmed as they say.