Quote:
Originally Posted by Ken Taylor
... how does a fibre system produce ringing current?...
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It doesn't, as has already been mentioned Virgin Media's legacy services are what is known as a HFC network (look it up on Wikepedia) the fibre trunk is long haul into an area and after that the conversion to copper is done at one of the larger street cabinets which then feeds a number of smaller cabinets that have individual copper "drop" cables to the customer premise, originally this was done using Siamese cable which had coax for the broadband and tv services and twisted pair copper for the telephone.
Virgin have now introduced "fibre to home" where the fibre is fed from the street cabinet to the outside of the customer premise, the conversion to copper being done at the external termination box - this means that the telephone service has to be provided via the broadband hub using VOIP principles - from the 29th March this year all new telephone installations have been provided via the broadband service and there are plans to eventually migrate existing customers over to "voice over glass" this will take a number of years though.
So even a fibre to home service is still HFC once it is inside the customer premise.
It will be some time before the fibre trunk goes direct in to the broadband hub and it will still be the circuitry in the hub which provides ringing current and power for speech.
Regards
Andrew