Strange Sipura/SIP Problem

Hi -

I am running Trixbox 1.2.3 under VMWare on Windows. Recently, I’ve noticed very choppy sound quality on incoming calls ONLY. When I use the same phone to place an outgoing call, the sound is perfect.

Initially, I thoght the sound quality was something to do with running Trixbox under VMWare and I even installed Trixbox on a dedicated PC and experienced the same problem (choppy sound on inbound calls only).

After testing (and pulling my hair out), I’ve isolated the problem to be something to do with my Sipura 2100 unit. I found I was only getting the choppy sound on incoming calls when the call was answered by a phone that is connected to a Sipura 2100.

I’ve tried “Factory Resetting” the Sipura with no luck. There have been no changes recently to my Trixbox set up nor any changes to the Sipura configuration.

Has anyone ever heard of this problem or have any thoughts on what could be causing this?

Thank you,


this is probably a network or provider issue.

To test, try register the Sipura device directly to the provider. Does that help?

I think the problem may lie with your provider or network settings, make sure the QOS is good… what provider do you have?

I have as my provider.

Also, do you have any info or do you know where I can find good, detailed instructions on enabling QOS on my DSL modem? I have Qwest as my DSL provide with and ActionTec modem but can’t find any information on enabling (configuring) it.

I have never had it enabled before and never had any problems not using it and I do know that the modem has the capability because I can see the QOS settings in the modem/router set up. It has some settings asking:

High Priority Bandwidth (Total Available 896)
Set IP precedence
Source IP
Destination IP

I would imagine the source IP would be the IP of the DSL modem/router and the destination IP would be the IP address of Trixbox??

Any help will be greatly appreciated.