Meaning to find out about this for ages. We are currently on Virgin Media cable broadband.
If there is a power cut, do cable connections continue to work? We do not have a UPS so our cable modem and router do not work when there is a power cut. But if we connected them to a UPS would we continue to have a working connection? Not at all sure what bits of the cable network need power and where that power comes from.
Same question, but for ADSL?
(The power cut the other day made me realise that we both now use laptops most of the time and can quite happily continue for a few hours without mains. So it is (arguably) worth getting a UPS if it will keep us working.)
If its just you then a UPS to keep the modems alive will keep ADSL and cable alive.
If its a wider area then the street cabinets used by cable may lose power and then their batteries will keep the phone lines up and may keep the broadband up for a short time.
If it includes the telephone exchange, then it should have battery backup and a diesel generators to keep it going so BT telephony and maybe ADSL should stay up indefinitely (they could drop non essential services like ADSL if there are supply problems within the exchange).
On the whole BT will probably survive a prolonged problem better than cable, but a few hours shouldn't stop the phone working and probably won't stop ADSL.
Rather than look for a UPS as a solution, you could consider using one of the 3G broadband services.
I have a vodafone 3g card. The card costs a flat £25 p/month for an unlimited data contract. Works pretty well, including during a recent powercut. I have many reasons to dislike vodfone, but the 3g service is not one of them.
I guess you are suggesting changing over completely to 3g? Hmm, my mobile is on Orange and I have noticed far more times the nearest "pole" is not working than we have power cuts - despite living very near a next of them (no - not sure who they all belong to - probably from all the mobile operators).
Also - I think I would *still* need a UPS for the router (which provides wireless access point). There are two of us (using up to five computers) so a 3g card in each would probably be an expensive approach, n'est pas? And it would not provide local switching (e.g. for printer) for when there is power to drive that.
But I do appreicate the need to think further. Am I making mistakes in undertsanding what you suggested?
The theory says yes, for ADSL at least, and I got the chance to find last Monday (we had a 7 hour power cut - a bit worse than your pansy power cut on Tuesday).
And, indeed, once I'd fired up my genny, my ADSL came straight back online (as did the cooker, heating, fridge, freezer, etc :-).
Good advice from Dennis. I had 3 days without power after the East Anglian storms a few years ago. Charged my laptop at work and could use the (built-in) modem in the evenings (no broadband then). OTOH the telephone exchange got flooded on another occasion - no phone or net for 3 weeks.
For your once-in-a-while needs, a UPS for the modem/router/printer sounds a good way to go compared to the ongoing expense of a 3G card.
(Another alternative is bluetooth connection to a GSM or 3G phone - and pay the per day data rate if your plan has one. I did this when I was based away from home for 3 months in a rented flat with no landline - orange had a =A35/month deal on unlimited data evenings & weekends. Data rate on GSM better than dial-up, windoze p*** poor at not messing up its configuration regularly - I'll try it again sometime with linux)
I wouldn't put any money on 3G staying up in a power fail situation. Round here when the power goes what happens on the cellphone networks varies between providers from disappears immediatly to disappears in a few minutes to disappears in a few hours. How they come back is also variable from straight away to many hours. The order of disappearing is not the same as the order of coming back. Quite a few people who have dropped their BT line and only have a mobile were caught out in the last long power cut...
I'd expect a cable phone to stay active for much longer, if it died at all. Being a wired service I think they have certain obligations to maintain a working line for quite a period after a power failure for emergency calls at the very least. Of course this would be for voice, the ADSL could be dropped as a power saving measure.
For the OP a UPS to keep the router and switch alive should work. Even if the ADSL does die you still have access to your LAN for file sharing printing etc. Watch the power consumption of your printer though, a laser printer doing a single sheet could take a significant amount of energy from your UPS batteries thus drastically shorting its run time.
I think you understand what I'm suggesting. You're right you'd need some battery for the router to continue working with more than one laptop.
It really all depends on how much redundancy you need to have.
I have regular (BT) broadband and also a 3g connection. The 3g pcmcia card will plug into a laptop. Also, the 3g card will plug into a slot on Linksys WRT54g3g router.
If the power goes out, I'm limited to one laptop. But where I am, the broadband line has more issues that the power line (sigh - hopefully now all resolved).
OK - thanks. Given the responses, for which thanks are due to all, I think a small UPS will do us just fine. We do have the possibility of modem dial-up should cable fail - but it is tedious.
There's not a 'simple' answer to this. Some of the street level cabs are line powered, and some take a mains supply. This is taken from the street lighting supply. The mains powered cabs feed power to the line powered ones via the coaxial links. So, you could have a fairly local power cut, and your Virgin sevice might well continue, if the street cab that you are connected to, is line powered from a mains powered cab that is outside the area that has the power cut. In this case, if your computer continues to run, along with your router and modem, as a result of being connected to a UPS, then you will still get an internet service. OTOH, if a power cut takes place in the area where the mains powered cab that feeds your line powered cab is located, but the power stays on where you are, you will lose your internet service for reasons that do not seem apparent to you. If the cut is widespread enough, you will almost certainly lose your service, as both you and the powering cab will be in the blacked out area. Also, you could be unlucky, and be connected to a mains powered cab just across the street, and when you lose your power, that cab probably will as well, so you would always lose your service when you lost your house power.
Caveat. Sometimes, street lights stay on when your house power goes off, because they are on a different phase from the one that has gone out. In this case, your internet service would probably stay on ...
Complicated, isn't it ?
An ADSL service should stay on, because BT's infrastructure is basically line powered from the exchange, and they have a large battery backup floating across the line, that should maintain exchange power - and hence outstation line power - no matter how long the outage (within reason). I believe that they have diesel generator-set backup also, to keep the batteries charged, in the event of a sustained outage.
Ho hum - re-re-evaluation time. I cannot remember a time when the street lights were on but our house off - nor vice versa. (I have lived in areas where this does happen frequently.) We are yards from a modest street box - I assume that is the sort you mean?
The ADSL answer you gave obviously applies to BT and BT-resold-as-someone-else services. Would that also be the case for own-equipment-in-exchange ADSL providers? (It is what I expected from the historic approach of Post Offic Telephones.)
Most copper phone line transport infrastructure is provided by BT and is sold to other operators, so any phone service that's not derived from a cable provider, who have their own trunks and fibre highways, should remain on. I would expect any independant operator to have equipment that behaved in the same way as BT's, but I cannot say for sure on that point. As far as the street lights staying on goes, I have had my side of the street go out, whilst the other side, and the street lights have stayed on. I guess it depends how the area that you are in has grown up around the substation, and how they've determined is the best way to keep the load on phases reasonably well balanced to stop the transformers jumping off their mountings.
The typical street cabs are a double-doored affair about a metre and a half across, and a little less than that high, perhaps. They are usually green, and have an ID number / letter stenciled on them in white. I don't think you can tell just by looking at them, whether they are line or locally powered. I'll ask my mate who works for them. If it is near your house, and is an NTL / Virgin cab, there's a very good chance that you are connected to it. Next time you see someone working in it, pop across and ask him if it is a line powered cab, and if it is, if he knows where the cab that's powering it is located.
Around here (Folkestone) you seem to be able to hear the powered cabs. We have a pair of cabs outside of our house and when I asked the engineer why there were two he told me one was powered and fed a load of cabs in local streets and one was a passive unit like you see everywhere. If you listen to the cabs carefully you can hear that the powered one has some fan cooled active kit in it (it also seems to have a more substantial lock
- probably an attempt to keep the fan cooled active kit in the cab :-)).
I'd never noticed until he said - since then I've noticed a few more with fan noise (although I get odd looks "listening" to them :-))
I'd be interested to hear if he gives the same explaination.
I have no idea about cable, but I would expect ADSL to keep on going. You don't necessarily need a UPS to keep the modem router going...
Check it's input voltage and whether AC or DC. IF DC and around 12v then a small (7amp hour) fully charged 12v gell cell would keep it running for several hours.
Well I do know that we are serviced by the green box (as you described) over the road. Just have to hang about waiting for a Virgin man... That doesn't sound quite right...
With three different makes of device (cable modem, wireless router, switch) which use, IIRC, three different voltages, plus needing to recharge the gel cell on a regular basis, I think it would be easier to stick with a UPS. Also, quite possibly we don't have suitable leads. But agreed - and it would make so much sense if everything could simply take that 12V directly.
Some operators certainly class 3g as a non-essential service that will be dropped on mains power failure. 2/2.5g systems will generally have at least 8hrs or so back battery back up on most cell sites. Beyond that its whether the revenue from the site is sufficient to justify man+van+genny to turn up and keep the cell running.
TBH a UPS running from battery power to AC, then wall wart back to DC for modem/routers always seems a bit daft to me. Ideally you'd could feed the kit direct from a 12V battery, although of some kit needs
5/6/9V inputs. I think there may be such a product on the market (i.e multiple regulated battery backed outputs).
Another thing, I often use my laptop when away in the camper van. I got a universal 120W laptop DC-DC from ebay for
UPSes often are mad. I have never seen a computer power supply that takes mains in, spits out the required 12/5 whatever and supports a battery. Yet that seems such an obvious approach.
The multiple voltages/multiple connectors are what make it awakward. Especially as Virgin could replace our modem at a moment's notice with one requiring a different input. (Actually - we could do that ourselves with the router or switch. But at least we could research and choose.)
There are PC power supplies for 12V LA batteries (10-15V). I've seen a stall at computer fairs which specialises in kit to run computers in vehicles, and they have these, but I don't think they've attended recently. 48VDC is also common as that's the supply in phone exchanges. Both are expensive compared with mains PSUs, as they are well off the track of commodity items.
You need to be careful with equipment which connects to the phone line. Sometimes it requires that its PSU provides a floating isolated output, or you can end up injecting stray voltages onto the phone line. Most ADSL modems probably have isolating transformers on the ADSL line, but it might be foolish to assume this is always the case.
Highly unlikely for this cell, there are far more sheep than people...
I agree I'd love a single power supply solution. I did look at it briefly with the idea of making something but almost every wall wart was a different voltage and some of the lower ones had fairly hefty current requirements.
My small 8 port network switch lives from a wallwart rated at 3.3v @ 3A, the DC cable is certainly hefty enough. The really annoying thing is that most of that power is probably reqired to light the LEDs. If all the ports are occupied with 100Mbps full duplex connections thats 24 LEDs all glowing away...
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.