[Asterisk-Dev] Hardware details for the Digium TDM400P

[Andrew Kohlsmith]

On Monday 20 September 2004 10:17, list at asd-group.com wrote:
> Its still nice to have the choice though, esp. when using small, low power
> PC platforms like the EPIAs. Much easier to swap-out a TDM module if/when
> grunt becomes a problem.

The EPIA really is not that low a performer.  Like I said I ran two channels 
just fine on a P90MMX, I just couldn't use iLBC since the 1-second transcode 
from ulaw was like 500ms.  :-)

The only way you can see what the system is capable of is to test it under the 
load conditions you want it to run.  I see dozens of posts saying "I have a 
FooTech KZ7MX088-PPZ-QC-Y will it work?"  The answer is always "TRY IT" -- 
check voip-info.org to see if the damn thing is blacklisted but other than 
that nobody can tell you.  If it doesn't work, tell the world though the 
wiki.

This is turning more into a generic rant, not one aimed at you in particular.

> Still, since I just bought my first TDM - the only non-DSP telephony card
> on the market - today, I better not sound like I'm complaining  :-)

Nah you've just asked the same question that's been asked a dozen times on 
-users.  My favourite questions are the ones where they want to use as cheap 
a system as possible but know nothing about VOIP or its requirements...  It's 
the completely wrong time to optimize.  Grab a standard system, try it, once 
you have a feel for it THEN you can try shaving cost.  

Early optimization is the mother of all fuckups.  Get it working, THEN 
optimize.

> BTW does the Digium DSP code use SSE (etc) when available?

That's up to GCC; I know that there are a couple of algorithms inside the code 
which get chosen at compile time based on what processor and #define macros 
are present -- basically one of the algorithms is specifically coded to help 
GCC make efficient use of the MMX/SSE ops.  Check your Makefile/zconfig.h for 
details.

-A.