Network Setup: Two locations, US and India . At US location, customer has a Callmanager, Unity, One PRI Gateway on 6500 switch using WS-6608 Module, and IP Phones. This PRI Gateway is registered to US Callmanager.
At India, customer has one Callmanager, Unity and IP Phones.
A intercluster trunk connects between India and US Callmanagers. G729 Codec is used in ICT. Pls find the Network Diagram attachment for details
Problem: When A user call from US PSTN and leave voice message, for a user in India, the message is received as dead air.
When a user call from US IP Phone, he can leave a message for a user in India and it works fine.
User from US PSTN Can leave a voicemail in US Unity server properly.
When Intercluster trunk is configured to Use G.711 codec, User from US PSTN Can leave the message in India Unity properly.