[Asterisk-Users] Qs about FXO/FXS cards

[Andrew Kohlsmith]

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.  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.

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.

-A.