[Asterisk-Users] help and guidance needed from gurus

[Colin Anderson]

I'm not a guru but I'll stumble through


>1. What hardware do I need for the server to accept incoming and outgoing
analog calls.


At minimum you need a hardware card that Asterisk can dial out on that
emulates an FXO port to connect with the PSTN,  and an FXS port to plug in a
standard analog telephone. There are two types of analog ports that you can
use: Foreign eXchange Office (FXO), which allows you to plug your  Asterisk
server into a phone line to connect to the outside world, and Foreign
eXchange Station (FXS) which emulates a standard phone line from the phone's
perspective, and allows you to plug in, say, a cordless phone. There are
many different cards out there, but probably the one you want is the Digium
TDM11B:


http://www.digium.com/index.php?menu=product_detail&category=hardware&produc
t=TDM400P


Scroll down to the sizing matrix at the bottom. You add ports by buying
additional daughtercards. Each card is limited to 4 ports which you can mix
and match. You can add multiple cards to a system for expandability but only
so far. I'd run maybe 3, max and then move on to a digital PRI line or a
channel bank. Some people hate these cards and some people like them, but I
find they work just fine in a SOHO or small office situation. 


Although it is possible to run an old crappy box (I use a P2-400 Deskpro EN
for my home setup) you would be well served by building a box correctly,
only once. I believe Digium recommends the ASUS P4P800E motherboard which is
actually a really good board. I'm an ASUS fan. 


As far as hardware config, don't get fancy and use PCI RAID cards or
anything like that. Asterisk has to control the system with near real time
latency, and anything that will "distract" it like servicing a RAID card
will lead to unintended side effects like echo. Regular hard drive. Also,
disable everything you can on the system: USB, sound, parallel, FireWire
etc. The system should *only* have what is necessary for it to operate, and
no more. Disable HyperThreading in the BIOS if your CPU supports it.
Asterisk is also mostly PCI I/O bound and not really CPU bound (unless
really really busy), so I'd look at a Pentium-M, underclocked for stability.
You get more stability with less power used, and heat generated, with an
underclocked Pentium-M.


I wouldn't bother with AMD. It will probably work fine, and a lot of guys
run AMD's but it's just another unknown factor you may or may not have to
deal with. 


A critical, and often overlooked factor, is the uniqueness of the card's
IRQ. The card must be on a unique and unused IRQ. How you do that is up to
you. Some motherboards allow you to specify the IRQ in the BIOS and other
motherboards can only change the IRQ if you swap slots. In any case, this is
critically important. 9/10'ths of the post on this list along the lines of
"I get echo / Sound is terrible / it won't work" are probably related to IRQ
and PCI bus issues. 


>2. What books, guides or companies or individuals can help me setup.


http://www.asteriskdocs.org/modules/tinycontent/index.php?id=11


http://www.voip-info.org


The Asterisk at Home http://asteriskathome.sourceforge.net/ distro is a
brilliant distro which allows you to learn without sweating it out over
things like compilers. You stick in the CD, boot, reboot, and your Asterisk
system is ready. It will wipe your hard drive without warning, so be
careful. 


>3. I need scalable hardware.


I'd say the above config would give you at least a couple dozen simultaneous
users. Above that, you need some big iron and an Asterisk consultant. A
newbie is toast rolling out Asterisk for more than a SOHO environment, some
of the issues with large installs are vexing and you need a pro. 


>4. What do I need in terms of technology and hardware to route calls
internationally.


-A good, consistent broadband connection with a static IP.

-A firewall that supports traffic shaping such as Monowall
http://www.m0n0.ch/wall/

-The brilliant AstShape script: http://www.krisk.org/astlinux/misc/astshape

-An account with a VoIP service provider:
http://www.voip-info.org/wiki-VOIP+Service+Providers 

-The above hardware install working good, no echo, users are happy with the
handsets, etc. 

-Patience and deductive ability

hth