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

[Miguel Molina]

randulo escribió:
> On Tue, May 26, 2009 at 5:31 PM, Danny Nicholas <danny at debsinc.com> wrote:
>   
>> I run my analog telco over cat5, but that's in-house and definitely not 3km. That sounds really far for current loop stuff.
>>     
>
> I was doing that too. I asked this same question a few years ago and
> the answer was 100-200 meters. This is just a quick rule of thumb, but
> it seems about right. 3km, I doubt that would work, but it depends, as
> someone said, totally depending on ohm's law :)
>   
What I think about this is, the length of the copper cable between the 
central office and home is usually several km, but definitely helped by 
the central office circuitry (current source instead of voltage source, 
that guarantees a minimum ringing voltage on the far end). What I don't 
know is, a FXS port behaves the same as a central office, electrically 
speaking? If that is so, you could extend your 3km of cable without 
problems, but I think you can have some noise problems depending on what 
places the cable has to go through.

> r
>
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-- 
Ing. Miguel Molina
Grupo de Tecnología
Millenium Phone Center
PBX: (+57 1)6500800 ext. 1201
Fax: (+57 1)6500816
Móvil: (+57)3138873587 

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