[asterisk-users] Maximum cable length for analog phone from FXS port

[Hans Witvliet]

On Tue, 2009-05-26 at 21:29 +0000, asterisk-users at rogg.is wrote:
> Appreciate all your input folks. Much of it very helpful in the greater
> context of the initial question.
> 
> Thank you for the suggestion of using various wireless devices, but I'm
> stuck with fixed wiring since this is a security/emergency phone(s)
> installation underground in large tunnels.
> 
> Also, switching to VOIP is not really the answer here because then I'm
> forced to solve a lot of power, repeaters/switches problems that arise. So
> I'm actually worse of than using the analog connections I think.
> 
> I do have some control over the wiring/cable chosen for this project but
> still forced to find a solution where I can feed the analog "phone line" the
> total 3km line distance.
> 
> I would love to find a way to do this in the Asterisk context with some sort
> of FXS feed, either from Digium (or compatible) hardware or any of the
> available ATA boxes. The Sapura box suggestion may be something and I'll
> look closer into that as well as continuing to look for other ways to do
> this.
> 

Ah! that explains.
As ordinary ethernet and wifi are impossible, and lines are too long for
ordinary analoge phones, options are limited.

Another idea is to use baseband modems, just like the pair used by
telco's for DSL. You can bridge 5KM or more...

If it's for a small number of phones, T1/E1 modems might be
impractible/expensive. And i presume you don't have a DSLAM lying around
there ;-)