[Asterisk-Users] Qs about FXO/FXS cards

[Bob Goddard]

On Monday 03 January 2005 12:34, Andrew Kohlsmith wrote:
> On January 3, 2005 05:35 am, Bob Goddard wrote:
> > What matters is the volts, amps and the voltage drop when the rails
> > are put under load. You have to ask yourself how many amps does the
> > mb require on each rail and can the psu supply it? The total power
> > supplied by the psu means nothing if it supplies all that power over
> > the 12v line but leave nothing for 5v.
>
> As I said, I measured the variation on the relevant lines with a 100MHz DSO
> when running under load.

No you didn't. What was the power load when the modules failed?

> There isn't any kind of significant droop or 
> swell in the lines -- not when asterisk is ringing a line, not when
> executing a kernel compile and a find / -name 'somethingthatdoesn'texist',
> not when doing both.

That is a simple "find", a better one would be "find / -ls", you should
also try running seti on all processors at the same time.

> Again, if the TDM400P is drawing more than a couple hundred milliamps over
> nominal when ringing all four lines, something is wrong in the design, and
> if your PSU can't source a couple hundred milliamps more than it is under
> normal load, you've specc'd it too close to your average draw.

If your motherboard requires 5amps when your psu can only supply 4, then
you're going to have trouble.

This IS a problem, just that it may not be in your case.


B