On 2/28/07, Eric Peterson <srcfoo at gmail.com> wrote:
> I was looking at moving our office to an Asterisk implementation and
> was checking out the cost of the FXO/FXS hardware. I've been looking
> at Digium's hardware, but was wondering if this was the best route to
> take.
>
> Any suggestions?
>
> We have six analog phone lines coming in and 8 analog phones connected
> to our current system. The current software isn't great and we can't
> use SIP based phones with it so I'd like to move to something that
> would support more soft phone clients.

My company has two production installations of Asterisk, both running
CentOS on newly-built (one year old, at this point) whitebox servers
and using Digium T1 cards. The T1 cards with hardware echo
cancellation were a lifesaver for us, not sure if any other
manufacturers are producing a card with that feature. Can't say much
about the FXO/FXS cards from Digium, besides the fact that they work
as expected. We have used them for testing, but do not have any in a
production server. Our environments use Snom 320 phones (no
soft-phones yet), and we have about 60-80 phones at each installation.

The biggest challenge we've had is with faxing. We ended up bringing
in dedicated analog lines from Qwest for our faxes at one
installation, but faxes at the other installation are running off
Sipura (now Linksys) SIP-to-analog converter boxes, and they seem to
work fine -- but they also use the faxes less than the folks who got
analog lines.

With your setup, you should be able to get two 4-port  FXO cards, plus
two 4-port FXS cards, and that would cover you unless you wanted to
add more analog phones or more than two additional lines.

I do seem to recall reading that having more than one card in a single
server can lead to performance issues, because the telephony interface
cards tend to generate so many interrupts on the system bus, and they
need to run in real time -- if you have too many cards, it will start
to show in performance rather quickly.

In each of our systems, we have one T1 card, and have had no
performance problems.

-- 
Dave Sherman
MCSA, MCSE, CCNA
Linux: Because rebooting is for adding new hardware.