Mediant 2000 Branch Truncation

[Sympology]

Hi there, only just discovered this forum so nice to be here. Hopefully I can be some help in the futrue. In the mean time we have an issue with possibly our AudioCodes Mediant 2000.

I'll try it brief, but it looks like the branch is being truncated, which is resulting in a 2 second delay on voice traffic being passed. For exapmple, we dial out and get ringback both ends. Answer at the remote end and it takes 2 seconds before any audio passes.
The route is Aastra 9133i Phone > TeleVantage 7.5 Server > AudioCodes Mediant 2000 > ISDN PRI

It is going through a firewall, but NAT is off and it is ANY ANY rules (according to our network team).
However if I do a call direct from my phone to the A/C e.g 0123456789@10.10.10.10, there is no delay.
When we did this, we noticed the branch is NOT being truncated.

We have a feeling this is the cause, but we have no idea what the cause, therefore not sure where to resolve.

A syslog from the Audiocodes is attached. Sorry if a bit to long.



Thanks for any help