asterisk users - May 2008 - trixbox, sangoma a200, dell poweredge 2550 issue

Hi all,

I have setup a Dell PowerEdge 2550 with a Sangoma A200 card with 2xFSO and
1XFS modules.

The PowerEdge specs are 1 x P3 1133MHz, 512MB RAM.
Sangoma A200 has 3 analogue PSTN lines connected.

This server is based in Office 1, with 5 users all with a Linksys SPA942
VoIP Handset.

There is another Office (Office 2) connected to here using VPN. There are
two users in Office 2 with the Linksys SPA942 VoIP Handsets, they are
connected also over VPN to the remote Trixbox.

When placing calls from either Office 1 or Office 2 calls are fine, there is
echo to start with (Echo training) but then it clears. Volume is ok, quality
is ok.

However when an incoming call is made to the office the quality is pretty
bad, crackles, low volume.

There has also been mention (In office 1) of some cross talk.


The Trixbox is plugged into the master switch in the server room, where the
various production servers are running, and all workstations are also
connected directly to the switch.

Is there any reason why I should be experiencing such bad line quality on
inbound calls from PSTN? Call quality is perfect when plugging in a regular
analogue phone. I am in the process of having all the VoIP handsets in
Office 1 connected directly to its own switch, and then connected to the
Trixbox directly to avoid server/workstation bandwidth issues, but I don't
think would solve the quality issues. Is the PowerEdge powerful enough to
handle the VoIP traffic. I am really at an end with this, and really need to
find a solution.

Any help, advice or pointers would be greatly welcomed.

Thanks,

PaulG.
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> Is there any reason why I should be experiencing such bad line quality 
> on inbound calls from PSTN? Call quality is perfect when plugging in a 
> regular analogue phone. 
So outgoing PTSN calls are fine but incoming PTSN calls have poor 
quality.  Do both parties hear the crackling, etc?  Can you reproduce 
this, ie if you use your cell to call in, does the problem occur every 
time?  What happens if you call your PTSN number from your handsets?  
Does the call go out onto the PTSN and come back in with poor quality?

Do you have other phone lines you can try the A200 with?  Have you asked 
Sangoma support?