System information

• If you need a modem, install an external unit that connects to a serial port. If you
must have an internal modem, you will need to ensure that it is not a so-called
“Win-modem”—it must be a completely self-sufficient unit (note that these are
very difficult, if not impossible, to find).
• Consider that with built-in networking, if you have a network component failure,
the entire motherboard will need to be replaced. On the other hand, if you install
a peripheral Network Interface Card (NIC), there may be an increased chance of
failure due to the extra mechanical connections involved. It can also be useful to
have separate network cards serving sets and users (the internal network) and VoIP
providers and external sites (the external network). NICs are cheap; we suggest
always having at least two.
• The stability and quality of your Asterisk system will be dependent on the com-
ponents you select for its architecture. Asterisk is a beast, and it expects to be fed
the best. As with just about anything, high cost is not always synonymous with
quality, but you will want to become a connoisseur of computer components.
Having said all that, we need to get back to the original point: Asterisk can and will
happily install on pretty much any system that will run Linux. The lab systems used to
write this book, for example, included everything from a Linksys WRT to a dual-Xeon
locomotive.
#
We have not experienced any performance or stability problems running
less than five concurrent telephone connections. For the purposes of learning, do not
be afraid to install Asterisk on whatever system you can scrounge up. When you are
ready to put your system into production, however, you will need to understand the
ramifications of the choices you make with respect to your hardware.
Power Supply Requirements
One often-overlooked component in a PC is the power supply (and the supply of
power). For a telecommunications system,
*
these components can play a significant
role in the quality of the user experience.
Computer power supplies
The power supply you select for your system will play a vital role in the stability of the
entire platform. Asterisk is not a particularly power-hungry application, but anything
relating to multimedia (whether it be telephony, professional audio, video, or the like)
is generally sensitive to power quality.
#OK, it wasn’t actually a locomotive, but it sure sounded like one. Does anyone know where to get quiet CPU
fans for Xeon processors? It’s getting too loud in the lab here.
* Or any system that is expected to process audio.
648 | Appendix C: Preparing a System for Asterisk