home router battery backup

Jay Hennigan jay at west.net
Thu Jan 13 02:35:20 UTC 2022

On 1/12/22 09:35, Scott T Anderson via NANOG wrote:
> Hi NANOG mailing list,
> I am a graduate student, currently conducting research on how power 
> outages affect home Internet users. I know that the FCC has a regulation 
> since 2015 (47 CFR Section 9.20) requiring ISPs to provide an option to 
> voice customers to purchase a battery backup for emergency voice 
> services during power outages. As this is only an option and only 
> applies to customers who subscribe to voice services, I was wondering if 
> anyone had any insights on the prevalence of battery backup for home 
> modem/routers? I.e., what percentage of home users actually install a 
> battery backup in their home modem/router or use an external UPS?

 From what I've seen on the market, home router or "residential gateway" 
devices with built-in battery backup typically only provide backup for 
FXS style analog POTS services, not for data, wireless, etc.

So, if you both pay for your ISP's analog phone service and still own an 
analog phone, it will work for a while. Nothing else will. This assumes 
that your local cable company both has battery-backed trunk amplifiers 
and that they service the batteries regularly. Many don't.

It's an FCC requirement to provide the ability to make emergency voice 
calls during a local power outage. This is an attempt to emulate the 
"good old days" when twisted-pair phone service with central office 
battery was the norm.

Speaking for myself, my networking gear is UPS-backed and my house has a 
Generac auto-start generator and ATS.

Most of our customers don't back up their home network gear. If they do 
it's most often an under-desk style UPS with 15-minute runtime that 
hasn't been serviced in a decade. Its battery is very much dead and so 
swollen that it can't be replaced without the use of some serious prying 

Jay Hennigan - jay at west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV

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