On 24/12/2020 11:50, Deloptes wrote:
> The Natural Philosopher wrote:
>
>> I have fibre to the premises AND it sill has a POTS analogue phone
>> service in the copper pair that runs with the fibre....
>>
>> No premises in the UK that runs on *ADSL* does NOT have a POTS service
>> on the same wires.
>>
>> They are due to all be phased out, it is true, but not just yet.
>> How can you tell? Line crackle. VOIP does not *crackle*
>
> I must agree with the frequency and broken wire as it makes sense if some
> connector or wireing is loose or damaged.
>
> Regarding the VOIP and TDM - it is also true. TDM replaced the analog
> switches by keeping the analog signal to the customer. Then came NCS.
> What I meant was TDM was decommissioned and even NCS being decommissioned in
> favor of SIP.
>

Yes, and SIP over IP over whatever.

Apparently my fibre is TDM optical fibre with passive splitters so that
hundreds of premises are fed bu a single fibre, and the fibre is split
into multiple other ones passively, and every modem gets its own time
slot, presumably encrypted so others cannot monitor it


> Regarding power outages - don't know about Germany and UK, but Austria and
> Switzerland have huge fines if the operators fail to provide emergency call
> services.
> So there are backup batteries for the switches and the lines. It is
> trivial - the batteries take over until the diesel power generator turns
> on.
Well that is true for UK POTS services. I once saw the exchange in
Guernsey - where there was two weeks supply of diesel in tanks to feed
the three gennies they had there. An island can be inaccessible for days
at a time...and power was I think via a single cable from the mainland

But my point was that modern UK practice is to allow consumers with FTTP
to have a POTS via SIP line service that *has no backup*. One assumes
that the mobile service stays up during power cuts.

Sure the exchanges will stay up BUT the local modem that decodes the IP
over Ethernet and sip from the fibre is not now issued with a battery backup

I am not sure how the service is in fact delivered over the fibre,. It
may not be sip., It could be a low bandwidth multiplexed digital channel
that simply goes through an A to D and has ring voltage and call
detection  added.


> The DMS100 had the batteries the size of a wall 50*4m. Compared to 4 Racks
> for a SIP switches with double capacity of subscribers.
>
>
The  good old days, when things woz done proper.


--
"The most difficult subjects can be explained to the most slow witted
man if he has not formed any idea of them already; but the simplest
thing cannot be made clear to the most intelligent man if he is firmly
persuaded that he knows already, without a shadow of doubt, what is laid
before him."

    - Leo Tolstoy

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