Phone Cable Question

[JohnW2]

Some confusion here. ... FTTH = Fibre To The House: .... The conversion is performed at the house at the customers expense.

True, in the sense that the conversion needs to be done by electronics, which need to be powered, and if the only thing entering the house is an optical cable, then that power has to be provided (and paid for), directly or indirectly (by charging batteries) by the customer.

All the "experts" try to tell us the 'Network' is entirely passive and all of the distribution is purely light based.

... and that's presumably true, isn't it, give or taken any ('electronic') boosters which may exist along the length of fibre optic cable runs - but end-users would be unaware of any of that, since all they would see in the cable entering their house would be 'light' ?

FTTC = Fibre To The Cabinet: ... The conversion to copper is performed at the street cabinet (the only service now available to me) and requires mains power.

Indeed.

All the "experts" try to tell us the cabinets contain battery backup.

That would clearly be desirable if one wanted the system to be resilient to failure of the mains supply.

My experience is different to what the 'experts' tell us, Eric and sureitsoff seem to be of the same opinion too: ..... In the adjacent housing estate the FTTH cabinets do have power so I assume there is more happening in them than just passive distribution. .... I know my local FTTC cabinet has 2 voids where the batteries are alleged to live, when there was a power cut we lost service although we still had power and WiFi but no internet or phone service.

Fair enough - so they haven't implemented the back-up facility which, as above, I would have thought was desirable.

In practice, of course, it's likely that in a fair proportion of cases, failure of the mains supply to the cabinet would be associated with failure also of the mains supply to the relevant customers - so the lack of battery back-up in the cabinet would make no difference.

 

[JohnW2]

Passive optical splitters. It's very clever technology.

As I've just admitted, I didn't read what Sunray had written carefully enough. Yes, of course, distribution as far as the customer's house will be (or, at least, will appear to be) totally passive - and I'm not sure that 'splitting light' is necessary all that difficult, is it? I mistakenly took him to be talking about what happens within the home - where the 'conversion' will obviously require power (which can only be supplied by the customer)

 

[JohnW2]

.... as he had frequent power cuts, and no mobile phone signal. ... First outage, went to report it, and phone did not work. ... So he can't have a smart meter, as no mobile signal, so it does not auto report any power outage. It seems we are going backwards.

True, a non-'smart' meter cannot report a failure to the electricity supplier, but that's a situation we've had to accept for a century or so.

However, there should be no difficulty in the provider of fibre-optic internet connection being made aware of the failure of communication through their cable (e.g. inability to ping cabinets, or whatever).

 

[davelx]

As I've just admitted, I didn't read what Sunray had written carefully enough. Yes, of course, distribution as far as the customer's house will be (or, at least, will appear to be) totally passive - and I'm not sure that 'splitting light' is necessary all that difficult, is it? I mistakenly took him to be talking about what happens within the home - where the 'conversion' will obviously require power (which can only be supplied by

The splitters don't just split, they do WDM mux and demux.

 

[JohnW2]

The splitters don't just split, they do WDM mux and demux.

Ooooh - if that's the case, then I have to agree with you that it is "very clever" to manage that 'passively' (to say the least) !

 

[SUNRAY]

The splitters don't just split, they do WDM mux and demux.

Yes but some splitters look just like BNC T-pieces so I doubt much goes on in those. One of my rental properties has several 'hanging' on the front wall courtesy of V*r*i* m*d*a; description available in post#9.

 

[davelx]

Yes but some splitters look just like BNC T-pieces so I doubt much goes on in those. One of my rental properties has several 'hanging' on the front wall courtesy of V*r*i* m*d*a; description available in post#9.

Yes, indeed. I'm referring to the in-street cab PoPs (Point of Presence), which take the exchange trunk and split down to multiple PoCs (Point of Connection), which then splits down again to the individual customers. The muxing is multi level. It's quite posssble to have a 2:1 WDM mux/demux in a T-piece, it's just a very cleverly contructed "lump of glass"

 

[JohnW2]

Yes, indeed. I'm referring to the in-street cab PoPs (Point of Presence), which take the exchange trunk and split down to multiple PoCs (Point of Connection), which then splits down again to the individual customers. The muxing is multi level. It's quite posssble to have a 2:1 WDM mux/demux in a T-piece, it's just a very cleverly contructed "lump of glass"

I would still be intrigued to know how on earth it works. On the face of it, I would have thought that each such "lump of glass" would probably have to be 'bespoke' in every case (e.g. according to the number and identity of the individual customers and/or PoCs), but I can't believe that woud be practicable?

 

[davelx]

There are standards governing the wavelengths used, so I would think (I retired just as this technology was being rolled out into provider backbone networks) you could get certain standard combinations and you'd have to plan your architecture accordingly.
https://www.fs.com/blog/dwdmcwdm-wavelength-itu-channels-guide-3149.html

 

[pcaouolte]

At my home I have available about 5 different fibre to the home providers to choose from. Most of them don't appear to use green cabinets like Open Reach, they use a cylindrical object fixed to a post to join their cables, those objects can't be powered as they only have fibre going to them. It appears that light leaves the telephone exchange and light arrives at my home without any electrical boosting anywhere along that path. My home is about 1.4km from the exchange measured in a straight line, it must be significantly more than that measured along the cable.

 

[ebee]

It is truly amazing what we can do nowadays , methinks a lot of it might have been driven in part to Sci Fi writers etc and a lot of the Sci Fi writers took from foward looking scientists what might be achieved in the near and mid future , one feeding the other but yest vice versa too.
The original Star Trek series etc had the actors walking about with a plastic board in hand pretending they were reading from and writing to it.
The Man from UNCLE picking pen out of pocket and saying "Open channel D" then having a conversation witth an associate on the other side of the world.
Truly amazing back then but nowadays all perfectly normal.
To track the first cave man inventing the wheel to todays life is absolutely astonishing.

Yet to teach folks to clip cables correctly and to actually get to speak to a real person about things can be a long soul destroying task compared to just a few years back.

If I had written a book about some of these changes 50 or more years ago I would have been considered bonkers - nowadays I would be correct (but I`d stll be bonkers - stark raving mad)

What will the next 50 years bring?
Walk into a telephone box and dial Brisbane then walk out and I am actually there in Brisbane?

World war 1 = the war to end all wars.
World war 2 = a rerun with better ways of killing each other.
Countless wars and skirmishes since - have we learned anything of value?
Oh dear.

Yet I still wonder at the Morse Key and a single wire if need be and an earth as return , what a good concept that was!

 

[ebee]

I have gone slightly off topic - sorry, its not like me to ramble

 

[JohnW2]

At my home I have available about 5 different fibre to the home providers to choose from. Most of them don't appear to use green cabinets like Open Reach, they use a cylindrical object fixed to a post to join their cables, those objects can't be powered as they only have fibre going to them. It appears that light leaves the telephone exchange and light arrives at my home without any electrical boosting anywhere along that path. My home is about 1.4km from the exchange measured in a straight line, it must be significantly more than that measured along the cable.

If one is to believe Mr Google's 'AI' friend (hard-to-believe though it may be) ...

 

[SUNRAY]

Yes, indeed. I'm referring to the in-street cab PoPs (Point of Presence), which take the exchange trunk and split down to multiple PoCs (Point of Connection), which then splits down again to the individual customers. The muxing is multi level. It's quite posssble to have a 2:1 WDM mux/demux in a T-piece, it's just a very cleverly contructed "lump of glass"

I feel very cleverly constructed "lump of glass" is just a little understated

 

[SUNRAY]

I have gone slightly off topic - sorry, its not like me to ramble

I don't find your rambles irksome, unlike some others