[asterisk-users] Electric usage of a tdm400p

[Bob Chiodini]

Erick,

It looks like the 2.5" laptop drive requires 5 watts to spin up. Adding
that to the 15 watts for the Digium card, leaves about 40 watts
available for the MB.  It's unlikely that the system will be producing
ring voltages when the drive is spinning up.  It depends on how
conservative you may be with real-time power management, e.g. spinning
drives down when not in use, etc.

I did not easily find too many ITX MB power requirements, but the one I
did find, required 45 watts (peak).

In the worst case, ringing 5 RENs on each Digium port and spinning up
the disk, you would be overtaxing the power supply.  I doubt you will
have 5 RENs on each port and all ringing, but you could.

In ages past, hard drives were the most vulnerable to poor power
regulation, but that may have changed.  With the higher cost of 2.5"
drives, I would not take any chances.  Beefing up the power supply would
also eliminate the need for manually managing power should you need a
CDROM or more power hungry drive in the future.  It's also one less
concern when troubleshooting the system.  

As Moj has pointed out, problems can occur when working close to the
edge.  I, too, have experienced similar problems when power was limited
and have had to, temporarily, resort to a "bigger" power supply to get a
system installed.  Then fell back to a "smaller" one in operation.

Good luck.

Bob...

On Wed, 2006-10-18 at 08:49 -0800, Mojo with Horan & Company, LLC wrote:
> I set up a similar system on an VIA Epia 5000, and I had issues when I 
> included the CDROM in the mix.  I had to use another ATX power supply to 
> complete the install, but then once I removed the CDROM drive I had no 
> power issues.
> 
> I presume you could install the OS with the CDROM drive installed and 
> the molex power connector REMOVED from the TDM card, then when the OS 
> was installed and you had network connectivity, power down, remove the 
> CDROM, add the power supply for the TDM card, then install zaptel etc.
> 
> Or just try it and tell us what happens, low power won't break it in my 
> experience.  Your cdrom drive might have a lower power consumption than 
> mine.
> 
> Moj
> 
> Erick Perez wrote:
> > Well Im planning to use a mini-itx, a laptop hdd and a 4fxs digium card.
> > the mini-itx comes with a 60W DC to DC adapter (80W peak).
> > So I need power to manage the hdd, motherboard,the tdm card.
> > A disk cable can be made available, but is not present as a factory default.
> > 
> > So My real concern is power.
> > 
> > 
> > On 10/18/06, Bob Chiodini <bchiodini at gmail.com> wrote:
> >> On Tue, 2006-10-17 at 11:59 -0500, Erick Perez wrote:
> >>> Hi people,
> >>> When you use a TDM400p with 4FXS i know i need to connect a 12V
> >>> connector to power the FXS lines.
> >>> Im not good at electric stuff so I ask...If I have a 60W DC to DC
> >>> adapter (80W peak) then, how much power will the TDM 400P consume? can
> >>> it be powered?
> >>>
> >>>
> >> Erick,
> >>
> >> Per http://en.wikipedia.org/wiki/Ring_(telephone) in the US the ring
> >> voltage is around 90VAC (20 Hz) with a current of 30 milliamperes (REN
> >> ~5).  This translates to 2.7 watts.  Assuming a DC/DC converter
> >> efficiency of 38% (probably low), you would need about 3.7 watts, per
> >> FXS module.  About 15 watts, total.
> >>
> >> What is the TDM card installed in and is a disk drive cable available?
> >>
> >> Bob...
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