This topic

Digital Voice and power cuts - mitigation

Bernie533 — Thu, 23 Sep 2021 21:38:36 GMT

I am to be moved to digital voice in the near future. A disadvantage of this is that the phone will not work if there is a powercut.

i am looking at getting the BT recommended cyberpower bbu. Looking at the instructions this is used to provide temp back up power to the ONT. does anyone know if i can plug a standard handset direct into the phone socket on the ONT for emergency use if it is powered by a bbu or would i also need a bbu for the smarthub2 ?

Would be grateful for any wisdom from the community as i can’t seem to find out.

thanks

Bernie

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Fri, 24 Sep 2021 05:21:42 GMT

@Bernie533

You would need a separate UPS, as you cannot plug a phone into the ONT.

BT can supply a backup power unit to power the home hub during a power cut, that is assuming that your Openreach optical modem has a battery backup unit. If not, then two separate units are needed.

Many people already have cordless phones, which would not work anyway, if there is a power cut.

This is for the smart hub 2.

https://shop.bt.com/products/cyberpower-back-up-for-bt-digital-voice-service--non-fttp--091297-FV54.html?ReferrerID=G600&utm_source=btcom&utm_medium=bt+marketing&utm_campaign=digital+voice+non+fttp&utm_content=G600

And this is for the FTTP ONT.

https://shop.bt.com/products/cyberpower-back-up-for-bt-digital-voice-service--fttp--097284-FV55.html

It would be much cheaper to buy a mains output UPS, and plug both the ONT and smart hub 2 into it.

Something like the Cyberpower BR700ELCD-UK (about £81) would seem more suitable, as you could also plug in any mains powered phones as well.

Re: Digital Voice and power cuts - mitigation

Bernie533 — Fri, 24 Sep 2021 07:36:25 GMT

Many thanks Keith, really grateful for the guidance

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Fri, 24 Sep 2021 07:42:48 GMT

@Bernie533 wrote:
Many thanks Keith, really grateful for the guidance

Its just seems a better option to have one UPS to plug everything in, including any DECT phones.

I suspect that BT have opted for a low output voltage (12V) unit, for customer safety issues, as not all customers would be competent to use a mains output UPS, as its likely someone will plug other things into it, and cause it to overload and shut down. It may also be that people have their ONT and home hub in different locations, so need separate units, adding to the expense.

Re: Digital Voice and power cuts - mitigation

Pjay37 — Fri, 24 Sep 2021 15:47:32 GMT

Keith

I hope I’m not butting in. I’m not sure of the etiquette of the forum!
I have been looking for clear information on BBU units and your post was just what I wanted. Because of a mix up over my FTTP installation I have been promised a free BBU unit to cover the mains failute situation, as soon as one is available. This is currently being looked at by Neil (moderator) on this forum.
From what you say it seems I would need two boxes one for the Hub and one for the ONT. Which ever way you look at it this is an untidy solution. I am tempted resolve the problem by purchasing a unit such as the BR700ELCD. The cost is not great, where safety of life is concerned, and it could also provide security for other small electronic items.
I’m out of touch with modern digital techniques in rhis area but I assume the ac output of units like these is such that it would not invalidate warranties or contractual obligations. Sorry if I’m fussing but my involvement in “converters” goes back to the horrors of vibrators and valve choppers!
Thanks for the information you provided. It was very much appreciated.

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Fri, 24 Sep 2021 16:18:06 GMT

@Pjay37

The UPS is an offline one, in that under normal operation with mains present, it simply passes the mains input, right to all of the sockets. It also makes sure that the internal battery is fully charged.

In the event of a mains failure, an electronic inverter which is powered from the battery, switches in very fast, and maintains the supply to three of the sockets on the top. The other three are only mains powered and are surge protected.

So you have three outlets which are protected from mains failure until the battery runs down. That enables you to plug in an ONT, a Smart Hub 2, and any mains powered phones.

The UPS output during mains failure, is a simulated sine waveform, which is compatible with all modern switched mode power units like those used on the ONT, Home Hub, and modern DECT phone systems. It will not invalidate any guarantee, as its the same sort of power unit that people use to protect their PC.

The amount of load on the UPS is going to be very low, so it should provide backup for quite a while.

Re: Digital Voice and power cuts - mitigation

Bernie533 — Tue, 28 Sep 2021 16:54:04 GMT

If i bought one of these as an emergency power back up to power the ont and the smarthub 2 do you know roughly how long it would keep them running for ?
Excuse my ignorance on this subject and am really grateful for any guidance. Trying to identify if I need to buy the two units from BT shop or a single one like this.

Something like the Cyberpower BR700ELCD-UK (about £81) would seem more suitable, as you could also plug in any mains powered phones as well.

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Tue, 28 Sep 2021 18:50:19 GMT

@Bernie533

Its a 700VA unit, which is quite large and capable of a 420W load maximum. It specifies nine minutes at 220W.

https://www.cyberpower.com/uk/en/product/sku/br700elcd-uk

The home hub and ONT are unlikely to be more than 40W, possibly much less, so I would expect it to provide backup for at least 45 minutes, possibly more.

Re: Digital Voice and power cuts - mitigation

Bernie533 — Tue, 28 Sep 2021 18:53:10 GMT

@Keith_Beddoe

Many many thanks Keith, genuinely appreciated. I believe there is a 1000va 600w unit as well. I am really grateful for your help.

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Tue, 28 Sep 2021 20:15:41 GMT

@Bernie533

The problem with larger units is that the internal circuitry can take more power that the actual load, so you do not gain as much as you would expect. Larger units are mainly for high power PCs which need time to shut down before the battery runs flat.

Conversion from the 12V backup battery, to 220V, does involve losses.

For those people with electronic know how, the ideal solution for very long outages, would be a 12V battery kept float charged, and then a protected feed from the battery, to the ONT and the Smart Hub, as I think they are both 12V.

Re: Digital Voice and power cuts - mitigation

Pjay37 — Wed, 29 Sep 2021 01:21:43 GMT

I bought a BR700ELCD ups last weekend.
I did an initial check using two 240V LED lights; three and four watts. All seemed to be OK so I switched off and allowed the battery to charge until I was sure it was fully charged.
I connected the Modem, Hub2 and Hybrid Unit (in the operational situation), to the protected outputs of the ups.
The battery lasted just under two hours. The phone worked correctly on digital voice.
I hope this is of interest.

Re: Digital Voice and power cuts - mitigation

Keith_Beddoe — Wed, 29 Sep 2021 05:44:55 GMT

@Pjay37

That information should be of use to many people, as an alternative to the BT units, provided everything is in the same location. It does have the advantage that existing phone base units can also be powered from it.

It also gives voltage regulation and surge protection to all of the units plugged into it.

Re: Digital Voice and power cuts - mitigation

Bernie533 — Wed, 29 Sep 2021 20:04:31 GMT

@Keith_Beddoe @Pjay37

Ordered one today folks. My thanks to both of you for your help and guidance. Massively appreciated

Re: Digital Voice and power cuts - mitigation

ChrisGee — Sat, 06 Nov 2021 10:12:58 GMT

@Keith_Beddoe Keith, you refer to an ONT which i gather should be part of the installation of a fibre connection. My line is still the original copper from the house to the pole in the road. Would a power supply such as you have suggested give me a connection if used to just power the Hub 2? We are registered as vulnerable and since i am being bombarded with leaflets and emails telling me we are being switched to DV i am obviously concerned that having to rely on a mobile isn’t ideal. Thanks for any advice you may have.

Re: Digital Voice and power cuts - mitigation

VeteranISPUser — Sat, 06 Nov 2021 11:29:04 GMT

@ChrisGeewrote:
@Keith_Beddoe Keith, you refer to an ONT which i gather should be part of the installation of a fibre connection. My line is still the original copper from the house to the pole in the road. Would a power supply such as you have suggested give me a connection if used to just power the Hub 2? We are registered as vulnerable and since i am being bombarded with leaflets and emails telling me we are being switched to DV i am obviously concerned that having to rely on a mobile isn’t ideal. Thanks for any advice you may have.

Hi @ChrisGee I am still on the original copper (FTTC) only and I bought a BR1000ELCD (only because it was cheaper than the BR0700ELCD at the time that I bought it). I am on Digital Voice (the HD phones are great and crystal clear for this old one). I estimate the UPS will give me WiFi and phones for two hours plus in the event of a power cut.

Re: Digital Voice and power cuts - mitigation

DaveS1234 — Sat, 06 Nov 2021 11:37:06 GMT

Just out of interest,

Does anyone know of the requirements for the network operator to provide back up power for the VDSL/G.Fast elements in the cabinets ? The (pre-DV) voice element was always backed-up from the exchange.

Regards,

Dave S

Re: Digital Voice and power cuts - mitigation

jac_95 — Sat, 06 Nov 2021 12:18:25 GMT

The DLAMs in the fttc cabs and for g.fast have a few 12v batteries I believe and are remotely monitored.

However in exchanges there were batteries and diesel generators. Though with the closing of the PSTN network and the move to VoIP and a shift to full fibre first you can't push power through a fibre cable that only carries light.

Have a read of this OFCOM document about the guidance on customers ordering battery backup/UPS https://www.ofcom.org.uk/_data/assets/pdf_file/0016/123118/guidance-emergency-access-power-cut.pdff

Re: Digital Voice and power cuts - mitigation

iniltous — Sat, 06 Nov 2021 12:18:29 GMT

If your question is do VDSL/Gfast cabinets have a battery back up themselves in case a power failure affects them ( as they are mains powered ) then the answer is Yes, there was a case where a VDSL cab was victim to a power outage , and the power company ( for whatever reason ) took an age to restore power , OR had to continually replace the discharging battery’s ( which can only keep the equipment running for a relatively short period ) , with fully charged battery’s until the power was restored .

Re: Digital Voice and power cuts - mitigation

jac_95 — Sat, 06 Nov 2021 12:23:57 GMT

To add to the batteries in the FTTC cabinet are just to power the VDSL equipment in the cabinet and not intended to put power down the copper line.

Re: Digital Voice and power cuts - mitigation

DaveS1234 — Sat, 06 Nov 2021 12:36:17 GMT

@jac_95 and @iniltous

Many thanks for your answers - I was not sure whether the Network element was subject to similar availability requirements that voice circuits have traditionally had to support during power loss.

Once again,

Thanks

DaveS