ISDN BRI channels are digital and there are two channels per "line":
64kbps (B-Channel) plus 8kbps for signaling (D-Channel).

With an analog modem you convert digital to analog and back again, your
signaling is all on same communication path, and the analog line has
interference. All those issues plus more reduces your overall bandwidth.
I'd guess 10 to 20% of all bandwidth is overhead. If you connect at
48kbps then realistically 38 to 43kbps is your real throughput.

Sprint is my local phone carrier. DSL isn't available on my DLC because
the cabinet serving my house is out of space. I know my cabinet will not
be upgraded in 2004 or 2005. At some point when Sprint does upgrade it
they'll add a DSLAM to my DLC and I'll have DSL (the box is < 500 feet
from my house too). Cable is no where near my house so...

I have two BRI ISDN lines in my house for Internet access. Each BRI is
about $25 per month plus an additional $13 per month to call KC Metro
area without paying long distance. My ISP charges $30 per month for
128kbps for a dial-up account. Toss in Federal, State, and local taxes
and funds per each line since they are considered "normal" phone lines
and I pay about $130 per month for 128kbps.

It really sucks compared to cable or DSL but it's about 4 times faster
than dial-up and that is worth it.

In the early 90's I know Bell Atlantic and Pacific Bell charged $150+
per 1 BRI.

>At 112K for dual-modem POTS connections, that might be 
>his easiest option for his remote location, and almost as good 
>as ISDN for the same general pricing (though the upload 
>speeds will still suck).