All FTTC cabinets have batteries that kick in in the event of a power cut.
Your car battery trick should be no different.
It's for the odd occasions where it's more than an hour or two, past the life of the cabinet batteries. Pretty rare occurrence now - last snow-in we had was 4 days or so, and the power stayed on right through.
My broadband basic info/help site - www.robertos.me.uk. Domains, site and mail hosting - Tsohost.
Connection - Three 4G, tbb tests normally 35-45Mpbs down, 65Mbps off-peak, 9-24 up.
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