[Asterisk-Dev] FXO - Question

[Steven Critchfield]

On Mon, 2004-09-27 at 12:24, Angel Diaz wrote:
> Hi all:
>     Does somebody know how many meters of cable is supported between
> Asterisk Digium-FXO cards and the telephone ?
> 
> My concern is about the impedances because my cards have to provide 50V to
> the phone. Suppose I would like to use in a
> building on the floor 25 where is my office and my server is in the floor 6
> where is the System Department

Just a reminder that this question has zero reason to be on a list about
the source code of asterisk. You question is about a specific vendors
hardware.

But in being nice and making the question go away, I will answer the
question.... sort of..

I qould suggest if you are worried about the voltage issue that you
remove the question from the PC where ultimately the powersupply of the
box has to be able to keep up with the need and pass it through a PCI
board. If you have that kind of space to cover, you should ideally look
into a channel bank and a T1 or E1 card to drive it. If you organization
is big enough to be spread over multiple floors, it would be wise to use
that setup anyways. The benefit here is that a T1/E1 line doesn't supply
voltage across the line, just data and therefore doesn't have as much
trouble over that distance. A channel bank is small enough that it would
be easily overlooked in most closets and would then bring your analog
line length to just a few meters to worry about plus be supported by a
device capable of driving longer lines anyways.
-- 
Steven Critchfield <critch at basesys.com>