[Asterisk-Users] Qs about FXO/FXS cards

[Shoval Tomer]

Lousy cordless phones, and some plain phone produce lousy voice quality
when the power circuit is used for anything else (especially fluorescent
lights).

Maybe this is relevant?

Using your DSL line for phones without proper filters is noisy too.

> -----Original Message-----
> From: Steven Critchfield [mailto:critch at basesys.com]
> Sent: Monday, January 03, 2005 6:53 PM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Subject: Re: [Asterisk-Users] Qs about FXO/FXS cards
> 
> On Mon, 2005-01-03 at 09:20 -0500, Andrew Kohlsmith wrote:
> > On January 3, 2005 08:01 am, Bob Goddard wrote:
> > > > 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?
> >
> > The actual current draw I did not measure -- I was looking for
voltage
> sags or
> > swells on the +5V and +12V lines during load.
> 
> While this has stemmed from my semi-educated guess, I would be most
> concerned with current instead of voltage. When I previously abused a
PC
> PSU it was driving a high torque 12v electric motor. The really high
> torque motors would peak out at 5 amps during spool up. That would
cause
> a PC PSU to pulse between something like .5 amps and 4 amps. If the
> spool up was controlled, I could keep the motor under 4 amps and the
PSU
> could drive the motor. I had no interest in the voltage because it was
> the current that ran the motor.
> 
> > > 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.
> >
> > yes it's a simple find but there would be significant disk/cache
> thrashing
> > when combined with a kernel complile, as I'd mentioned.
> 
> Okay, link this to my rambling above and you would see that by
thrashing
> the disk, you are actually keeping the spindle spooled up and not
> measuring the spool up draw. My guess is a spooled down machine
getting
> a random incoming call that then must generate ring and spool up the
> HD(s) to start writing logs at the same time on a questionable PSU.
> 
> > > If your motherboard requires 5amps when your psu can only supply
4,
> then
> > > you're going to have trouble.
> >
> > Yes I completely agree with you here.
> >
> > > This IS a problem, just that it may not be in your case.
> >
> > I am willing to bet that my case is the more general case here --
The
> TDM
> > current draw just is not a big draw, or at least it should not be --
> > certainly no more than a HDD during heavy seeking or a video card
during
> some
> > intense gaming sequences or even some of the larger data
acquisition/DSP
> > cards I've used in the past.
> 
> As far as I know, with the exception of a couple of video cards that
> resorted to an external PSU, all video cards have to draw from the PCI
> or AGP bus. This means the TDM card is likely to draw more than the
> graphics card.  Heavy HDD thrashing uses less power than the spooling
up
> of an idle drive.
> 
> I'm also starting to wonder about specific phones now as well. While
> this next bit of rambling is not asterisk related, it is phone related
> and something to consider. While out at my mothers house, she had a
> phone next to her PC that wouldn't ring and when used would cause the
> DSL to drop out. I happened to buy a new cordless phone for her and
> replaced a phone that was working elsewhere in her home. After putting
> the new cordless phone in, the phone by her PC started ringing
properly
> and was able to be used without dropping the DSL.
> --
> Steven Critchfield <critch at basesys.com>
> 
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