Hi folks,

We have setup a new Vigor IPPBX 2820 in our offices and are using Cisco 303 VoIP phones to connect. Internal calls are crystal clear but as soon as we dial the code for the outside line, there is an awful crackling noise.

I have traced the incoming line all the way to the PSTN wire going in to the LINE on the Draytek and it's similarly clear. The crackle seems to be introduced somewhere after this, inside the device. I have updated the firmware, the system prompts and everything else is working nicely. I have tried changing various settings with regards to codecs but still no luck.

Any and all pointers and suggestions are most gratefully received.

Many thanks,
Paul

Please, does anybody have any suggestions? The phone line going in is clear and the internal calls are clear, just the PSTN bridge is unbearable. I have listened on the PSTN when a VoIP->PSTN call is being made and there is no crackle on the PSTN side, just the VoIP side.

You could try to earth the PBX. The 2820IPPBX mysteriously doesn't have an earthing point, so you need to use the yellow shielded cable supplied to plug into a metal (earthed) Ethernet switch and that should fix it.
Not exactly elegant and hopefully Earth bonding will be implemented properly when the 2820IPPBX is updated but for now it's your best chance of a fix.