Battery Backup at FTTC and in Exchange

Does the Battery Backup in the FTTC Cabinets supplement or replace the existing Battery Backup installed in the Exchanges; or is it "totally isolated"?

For example, if the Mains Supply to the FTTC Cabinet was lost for long enough for that FTTC Battery to fully discharge, would only the VDSL BB be lost, whilst the basic PSTN Services continue to function?

I would imagine it is totally separate.

Voice will continue so long as exchange has power, mains, battery or generator

Voice will continue so long as exchange has power, mains, battery or generator

Yep, I know

Cabinet power is independent of the exchange power.

I think the OP is aware of that, but seeing as on FTTC the PSTN service is routed through the cabinet DSLAM is asking if power failure and battery exhaustion there would cause PSTN failure.

Similar in concept but not technically to the way a DECT phone won't work.

Or is the connection at the DSLAM somehow fail safe and would allow the exchange-provided power to pass through in such circumstances?

the pstn service is not routed through the dslam

All the DSLAM is doing is overlaying a radio signal into the copper pair, it is not replacing the exchange side voltage.

So in effect, the connection/overlay of the VDSL signal in the FTTC is NOT a DC type coinnection; but probably isolated capacitively and/or inductively.

Whilst the Filter/Link does allow the Exchange DC (and conventional phone signals) to flow through, onwards to the house etc.

Edited by deleted (Fri 04-Sep-15 12:29:17)

The filters are passive ( not powered) so pstn will still work if the fttc looses power completely