One way audio problem

Hi everyone,
I am having a one way audio problem with MV-370 VOIP GSM Gateway. This is the setup:

MV-370 Gateway (behind firewall and proxy) > Tunnel Server ( http://your-freedom.net ) > UK Softswitch (Sip proxy server)

Using the technique above I am able to register the gateway to the softswitch in UK through a Tunnel bypassing the firewall and Proxy of ISP using SIP.

But the problem occurs when i call like below:

My PC Softphone (UK) > Softswitch (UK) > Tunnel Server > MV-370 Gateway > PSTN

The call from my softphone rings at Myanmar PSTN, when they pick up, it connects and they can hear my voice very clearly. But I cannot hear them. We have tried different codecs..Still same.

Somebody please help. Don't know what to do now.

Thanks

Hi Voipmyanmar And VERY Warm Welcome to Voipuser!!!

You should look in old topics to solve it.

It is basically NAT issue(firewall blocking any Ports for UDP)
Eitherway.

Look at this topics.

port checking utility..

http://www.voipuser.org/forum_topic_1022.html

X-lite setting -- thread

http://www.voipuser.org/forum_topic_322.html

Old threads on 1 Way Audio

http://www.voipuser.org/forum_topic_5101.html

http://www.voipuser.org/index.php?name= ... ght=#22051

http://www.voipuser.org/forum_topic_5358.html

Fuel Voip!!!!