No audio on incoming calls with SPA-2002

[W1IRH]

I am using the SPA-2002 behind a Linksys WRT300N router. I saw at least one other post with a similar problem and tried everything suggested in his posts, but still am having no luck.

The symptoms are:
It appears that when the SIP session is locally initiated, everything is OK. We have no problem at all on calls we originate.
On received calls, the calling party can hear me, but I can't hear them.
When the SPA-2002 is connected directly to the cable modem, it operates normally.


So far I have tried:

Updating the SPA firmware to the latest version (3.1.20)
Tried adding STUN server support (stun.vtnoc.net) and mapping port 3478 to the SPA
Changed SIP port to 5070
Directly mapped ports 69 UDP, 5070 UDP and the RTP port range to the SPA
Set a DMZ to the SPA
Substituting a D-Link DI-604 router for the WRT300.. same behavior :(


Oh, and to make the problem more interesting, I have another VOIP line from Vonage with an ATA186, and that one works just fine. And, yes, one of the first things I tried was disconnecting the ATA186.

I'm about ready to throw in the towel on this one.. Is anybody using a SPA-2002 successfully?

Any advice/suggestions are gratefully appreciated.
Thanks.

:confused:

[W1IRH]

Just to recap the problem.
On calls I originate, the audio works fine both ways, but on an incoming call, there is no audio path for incoming audio. In other words, I can't hear the caller although he hears me OK.

My solution (finally!):

Log in to the SPA-2002 with the admin/advanced menu.

In the NAT Settings section of the Line 1 tab:

Set NAT Mapping Enable to yes.
Set NAT Keep Alive Enable to yes.
If you are using Line 2, then these changes need to be made on the Line 2 tab instead.

In the NAT Support Parameters section of the SIP tab:

Set STUN Enable to yes
Set STUN Server to stun.vtnoc.net
Set EXT IP to 0.0.0.0
Set EXT RTP Port Min to 0

This worked for me.. If you're experiencing the same problem I hope it works for you as well.