WRP400 - Inbound calls not activating

[ur17-cisco]

Outbound calling works fine.
When I receive an inbound call, the phone rings, but when I pick up the phone, the conversation does not get established.

This seems like a routing or firewalling issue, but so far I have not found the solution.
I am connected to a cable ISP: the WRP400 gets the public IP address, but I could not find any routing/firewalling setting for the voice part.

A friend lent me a SPA-2012, and, with a totally similar configuration, inbound calls work on it. Also: incoming calls work on a softphone that I run on a computer in my local network.

I have tried to give back the router, assuming that it was defective, but even the new one behaves the same.

Can anybody help me, or point me to a previous thread where this issue was discussed and solved?

Thanks in advance.

PS: The firmware is 1.00.04.c I have not updated it, as the Linksys site offered it only in their USA site, and not elsewhere, and it did not specify whether the new version was suitable for european users.
PS2: I am attaching a log of a phone call attempt and the configuration of my VOIP part of the router.

[Alberto Montilla]

Hi Andreas;

Thanks for your update. Happy to see that you can now use the device to its full "voice" capability.

Regards
Alberto

[ur17-cisco]

Hi Alberto, hi Andreas,

I can confirm that, with that setting, it works for me too.

Thanks,

Filippo

[rajnivanza]

Hi Friends,

I have also face same problem.

Outbound calling works fine.
When I receive an inbound call, the phone rings, but when I pick up the phone, the conversation does not get established.

I have call from inside NAT extension number to Outside NAT extension ( Outbout call ) then call get estabished and two-way audio work fine

but when I have call from Outside NAT extension to Inside NAT extension (Inbound call ) then  phone rings,

but when pickup the phone, audio is not present.

During inboud call RTP packets are not transmit whereas Outboud call RTP packets transmit successful.

Sometimes, Inbound and Outbound call only one-way audio present.

Can anybody help me, or point me to a previous thread where this issue was discussed and solved?

Thanks in advance.