Telecom call this a Tie Line.

My mother had a cafe in Wairoa when i was 15, and we put in some computers for people to use for free. Problem was there wasnt any adsl, and on a business line, unlimited internet for $24.95 a month cost 4c a min for the local call charge.

So i investigated routing it through our house nearby. Telecom offered this service and it was called a Tie Line. Basically for every exchange it passed through, it added more cost. I think it was something like $200 per month. Thankfully for us it was only one exchange away (1km max)

So I hooked up the tie line to extn 6 of our old sbx6 pbx system and just had the modem dial home, which then dialed out to the internet. Used a proxy server to speed things up.

Lovely times.

Of course now days i would get a VDSL bridge and run that over it. Unless a chorus tech came knocking and said I was breaking their spectrum planning as the line passed through the exchange.