[asterisk-users] Analog FXO or IAX DIDS for new facility?

[Stephen Fierbaugh (PBT)]

I am a Linux sysadmin who has been tasked with developing the phone 
system for our nonprofit's new US headquarters building.  We cannot 
bring our legacy phone system with us, so I am building this completely 
from scratch.  I have already read "Asterisk: The Future of Telephony" 
and done a fair amount of googling.  I am completely sold on Asterisk, 
and the new building's phones will be a mix of SIP handsets and softphones.

I am confused about one thing:  Should we be getting a block of analog 
circuits from the local telco (probably AT&T), connected to the server's 
FXO cards for in-bound and out-bound POTS calls; or should we get a 
block of DIDS numbers from one of the plethora of providers available 
over the Internet, and then have our server connect POTS calls by IAX to 
the DIDS provider?

We are unsure whether we are going to have separate numbers for everyone 
in the organization, or just 1 US phone number, with everyone in the org 
having their own extension number.  That probably largely depends upon cost.

We will have 75 people in the building.  We have no data on call 
patterns or usage (because our legacy system belongs to our current 
facilities host), but we currently have 4 lines for 35 people and on 
unusual occasions they all get busy.

An additional consideration is that we also have 300 other people 
scattered literally world-wide, and the next logical future step is to 
start providing VOIP links for them, as well.

Thanks in advance for your advice.  Any other suggestions, such as # of 
lines sizing info or reputable DIDS vendors (if that's the answer) are 
also appreciated.

-- 
Sincerely Yours,
Stephen P. Fierbaugh<stephen at fierbaugh.org>
Pioneer Bible Translators<stephen.fierbaugh at pbti.org>
Pronounced: "Fire" as in hot, "Bah" as in humbug!

"                                            " John 3:16 in over 3,000 languages.