[Asterisk-Users] 2 4-port T1 cards

[Mark Spencer]

> 3. Dual MB won't help much in pure telephony.
> 	In pure telephony, you are basically dealing with serial line
> 	IO. A T1 is little more than I long distance serial line. 8 T1s
> 	is just 11.7megs per second each way, or 23.4 megs in and out.
> 	Not too much for a good machine to do. Granted, if you are doing 	VoIP
> then you add another set of ins and outs with compression in 	the middle
> of it too. This is where the second CPU comes in handy.

Actually, with Zaptel, and the T400P especially, dual CPU makes a *big*
difference.  The T400P and E400P are slave-only designs, so the CPU spends
a lot of time just cramming I/O down the PCI bus.  Having a second CPU
free to do work will definitely help.

> 4. AGP Video.
> 	Make sure not to use the frame buffer, it has been reported that 	the
> frame buffer generates large amounts of interupts and will
> 	degrade the performance.

Don't underestimate this effect or think that a fast CPU will get around
it.  frame buffer is a definite no-no because it disables interrupts
during screen redraws which take an enormous amount of time.  If your call
quality drops while you're playing quake on your PBX, don't come crying to
us ;-)

Mark