Hi,

Our company uses Iridium Satellite phone as a backup communication. But when we are making calls to out Lync EV DID number, the call comes in, but when we accept the call there is no audio heard on both sides.

If we call the same Lync EV DID number using our cellphones(AT&T / T- Mobile) there is both way audio.

The under lying Infrastructure is ISDN PRI trunks from the carrier, terminated in Sonus UX2000 SBC which has TLS trunk with Lync 2010 environment.

Any body has faced the same issue in their environment and found a solution please help.

Hi,

Would you elaborate the Lync environment about Mediation server part?

Did you enable Media bypass? If so, please disable it and try again.

Please also double check any firewall on the media path blocks the traffic.

More details:

http://technet.microsoft.com/en-us/library/gg398833.aspx

Best Regards,

Eason Huang