Here's an attempt at an interesting article on the robustness of UK telecoms:
http://www.theregister.co.uk/2008/11/28/wireless_survivors/

To summarise: mobile phones are not intended to be robust, but landlines are and ought to last 14 days without grid power or human attention. Their use might be restricted, though. The government has additional communications resources, and could use radio to inform the public.

The article doesn't say how long grid power itself could be expected to last. There is some valuable criticism in the comments section.

The context is a TV drama called "Survivors", about disease killing off 99.9% of the population. That production has virtually nothing of value to this site, in my opinion (and I think it's rubbish artistically, too).

Must be different in the US. Here the wireless towers have batteries and the larger companies have generator trailers they drive around between towers to charge them up. I didn't get a land line when we moved because I was tired of it never working, the land line companies just don't care.

Ok, this must be drastically different than A.T.&T.

It is important to note that all land line telephones are run on "battery" 48VDC. The grid electric supplies the charge to the batteries that power the system at all times.

Between the military and building homes, I worked for A.T.&T. They have added stand-by capacity in all of their generators for 7 days. Then you are purely on battery. As each central office (CO) goes to battery, you have 24 hours.

Each Pair Gain (fiber to copper, so it can be used in the home) has 4 to 8 hours battery capacity. These must have a generator brought out to them.

Cell sites generally have a small generator on site, or someone brings one out. Their battery capacity for the radios is about 8 hours, but this battery will not run the air conditioners. Because of this the radios get hot and shut down.

I could go on a long course regarding how the civilian land lines work here in the states, but: 1 too much time; 2 off topic.

Suffice it to say, a long power outage will kill cell sites before land lines due to availability of portable generators. Maybe I think this one thru, and start a new thread elsewhere on the forum once I wake up fully.

Hmm, I wonder how many of the population today using landline have only wireless phones in their home? At idle mine would only last maybe two days at most. My Blackberry will go a good three days on nominal use.

I think the weak link for the vast majority is still going to be how long the battery in their wireless landline phone lasts. I don't use landline anymore. But then again, I have alternatives at my disposal.

During that big midwest blackout Verizon cells stayed up, they had at least a couple days of power and generator trucks that drove around topping off the battery banks.

My local phone started out at ameritech then became SBC and then AT&T and we never had decent service through all three companies. Was paying $40 / month for just a simple land line and never knew if it was actually going to work when we went to use it. There were times when I would use the internet to report my phone or power was out.

Do you live in an older or rural area. If you have DSL through the same line as voice, both should be out of service.

Good luck

Thats what I replaced my land line with as my wife just had to have a home number. The cable modem has a decent sized battery inside it and I've had it unplugged for up to an hour now while remodeling the basement and its stayed powered up.

The problem not addressed is dial tone. I know a guy who lived in New York during one of their long power outtages years ago. No one could get a dial tone on their cell or landline. He said people were going in public buildings with their cell phones on as flashlights so they could find payphones -- payphones worked, but you had to have quarters or some other way of paying for the call, and your calls to local numbers probably wouldn't go through. Long distance calls did, though.

When a disaster happens, everyone tries to get on the phone and make a call, so it doesn't matter if the phones are "working."

Mine does anyway. Even if it didn't I have all that on a UPS, will run for hours on battery if needed. Next step is to upgrade the batteries and feed solar into them.

Does the battery runtime change if you are pushing lots of bits through them?