[asterisk-users] Digium FXS specifications and limits Question

Barry Miller asterisk-users at notanet.net
Fri Mar 2 10:26:06 CST 2012

On Thu, Mar 01, 2012 at 05:35:34PM -0700, Nunya Biznatch wrote:
> Howdy All,
> I'm considering Asterisk / Digium as a replacement to my existing phone 
> switch. I need to continue to be able to push analog lines between 
> multiple buildings in a campus environment.
> The Digium Analog 410 Card manual states it's not recommended to go 
> beyond 1500 feet distance for an FXS card, and no line should leave the 
> building or be bundled. The 2400 Series Manual does not have this same 
> notice. Should it?
> My potential application will be pushing all of 1500 feet and maybe a 
> teeny bit more. Analog lines will be bundled into PE-89 type 
> direct-burial rated cable in capacities ranging from 100-pair to 
> 500-pair. All cable pairs are 24AWG. All cable is privately owned by the 
> organization. All cable is professionally terminated on each end to 
> grounded building entrance protection with lightning blocks / surge 
> protection. This infrastructure has been in place and working on an 
> existing "old school" digital switch with port cards that don't have 
> lightning or surge suppression built in, just like the Digium cards.
> Has anyone run a similar configuration and can speak for or against such 
> an idear?

If you must do this, Mike Sandman (and probably others) has a line of
loop extenders.  I've used his stuff before to keep old POTS stuff


These devices may also give you a little more lightning protection than
you already have, but I wouldn't count on it.


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