One pair was on eBay for $25 just yesterday, lessee:

  http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=54966416,
contact jtyoungman@aol.com, these didn't sell so I presume he'll re-list
them?  If not, B&B [http://www.bb-elec.com/welcome.html] usually has
this sort of thing, at semi-reasonable pricing, also Black Box
[http://www.blackbox.com/].

  B & B Electronics wants about $40 USD apiece for these, see Page 11 of
their catalog (It's downloadable as a .PDF file.)  They also want $15
for the power supply, which you may not want to pay <G> Theirs are
already opto-isolated (You want optoisolation, for a 2-3 km long line!
You knew that already though <G>)  (I'm paranoid, maybe, but I'd have
lightning rods at each end - if appropriate <G>  Mother Nature is pretty
powerful...)

  Black Box: See page 524 of their catalog, the # ME739 series is what I
suspect MIGHT work, but these are transformer isolated not
opto-isolated, and they want $170 apiece for these, so think B & B maybe
<G>

  Mark

Pedro Drummond wrote:
>
> Yes, well data rate is not a problem, I will need to update the reading once
> in a while. So I can send it as slow as I have to.
>
> Do any of you have links to current loop modems ?
>
> Thanks a lot.
>
> Pedro.
>
> At 07:04 15/01/99 -0700, you wrote:
> >How about short-haul modems?  I think thats what they are...BlackBox makes
> >some I believe.
> >
> >