Assuming they're the same as my home, they come with a battery backup unit which powers the landlines (as landline phones are normally powered from the exchange - and thus work in power cuts)

Of course people who still have landlines nowdays probably have cordless ones that require a powered base station, but I assume that at least in the UK, the line must be left powered during power cuts.

Nope, none of that in France - just a standard fibre socket, and the ISP gives you an ONT that turns it into Ethernet, which then goes into a router.

I've never actually seen any ISP there even advertise a battery backup unit, I guess if you need they'll just tell you to buy a standard UPS.

No idea how it works in the UK, haven't had consumer-grade fibre here yet, always just got business-grade stuff where you bring your own hardware & UPS if needed.

> No idea how it works in the UK, haven't had consumer-grade fibre here yet, always just got business-grade stuff where you bring your own hardware & UPS if needed.

I've installed (business) fibre links on 6 continents, handoff has always been a pair of fibres (usually LC or SC), usually with a /30 ipv4/ethernet, and a routed network pointing at my end of the handoff (or in the case of private peering, a BGP configuration)

My FTTH from BT is a single fibre (no idea if it's compatible with generic bidirectional sfps). This runs into an Openreach converter box - powered by a battery backup - which has 2 phone outputs and 4 rj45s.

My core mikrotik plugs into one of the rj45s and establishes a pppoe session with BT's network.

Oh that's interesting, I've lived in two FTTH properties in the UK, the ISP installed a battery backup in both properties just for the phone line as otherwise the landline would die if the power went out and apparently that violates some UK law about landline availability.

Given the rate at which people -- especially younger people -- are getting rid of landlines in the UK I suspect in the future this'll be a non-issue. To be honest I'm not sure why I have a landline still.

Which ISPs was that with?

I’ve never actually had a landline on fiber ever. It was always just standard Ethernet on top of which I run whatever I want (SIP client or WiFi calling).

How was that “landline” working? Do they give you a little converter that turns Ethernet into a standard phone jack (and converts it to SIP internally), or is there some other non-IP based signaling for that voice traffic?

Is that by law? To have a Standard Fibre Socket? God I wish every government would implement just that.