[asterisk-users] Reverse-ATA : Using PSTN lines to connect to Asterisk

Alex Balashov abalashov at evaristesys.com
Tue Apr 10 07:25:11 MST 2007

Hi Mike,

   You should be looking at ATAs that have FXO, rather than FXS interfaces. 
Most ATAs come with FXS ports so that you can connect analogue phones to
them, but in this case you're wanting to take PSTN lines from the outside,
so FXO is desirable.

   Second, you'd have to make sure that the "ATA" supports the sort of 
application you're using it for;  most are manufactured on the opposite 
premise.  I am actually not sure offhand of any ATA firmware that I know 
that I imagine would work this way, although I'm confident it exists
as consecutive back-to-back analogue<->VoIP adaptations in many scenarios
can get quite complex and requires that flexibility.

   Basically, you're looking for a small IP PBX that uses SIP internally
among its private nodes and takes PSTN trunks from the outside.  That's 
what PBXs typically do.  :-)

   If all else fails, you can always roll your own functionality of this 
nature by using FXO cards in Asterisk.  There are various distributions
that package it in a very lightweight and reusable manner specifically
for this type of purpose, or you can roll your own if it's scalable

-- Alex

Alex Balashov <sasha at presidium.org>

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